Mitsubishi Electric ecodan EHST20C-VM6HB User manual
SERVICE MANUAL
CYLINDER UNIT
No. OCH531
CONTENTS
1. REFERENCE MANUAL................................... 2
2. SAFETY PRECAUTION................................... 3
3. SPECIFICATIONS............................................ 6
4. PART NAMES AND FUNCTIONS .................. 7
5. OUTLINES AND DIMENSIONS..................... 10
6. WIRING DIAGRAM.........................................11
7. FIELD WIRING............................................... 24
8. WATER SYSTEM DIAGRAM......................... 28
9. CONTROLS ................................................... 33
10. TROUBLESHOOTING................................... 53
11. DISASSEMBLY PROCEDURE...................... 69
12. SUPPLEMENTARY INFORMATION ............. 85
13. SERVICE AND MAINTENANCE ................... 86
September 2012
Note:
•This manual describes only
service data of cylinder unit.
•RoHS compliant products have
<G> mark on the spec name
plate.
R410A
MAIN CONTROLLER
PARTS CATALOG (OCB531)
[Model name]
EHST20C-VM6HB
EHST20C-YM9HB
EHST20C-VM6B
EHST20C-YM9B
EHST20C-VM6EB
EHST20C-YM9EB
EHST20C-VM6SB
EHPT20X-VM2HB
EHPT20X-VM6HB
EHPT20X-YM9HB
EHPT20X-VM6B
EHPT20X-YM9B
[Service Ref.]
EHST20C-VM6HB.UK
EHST20C-YM9HB.UK
EHST20C-VM6B.UK
EHST20C-YM9B.UK
EHST20C-VM6EB.UK
EHST20C-YM9EB.UK
EHST20C-VM6SB.UK
EHPT20X-VM2HB.UK
EHPT20X-VM6HB.UK
EHPT20X-YM9HB.UK
EHPT20X-VM6B.UK
EHPT20X-YM9B.UK
CYLINDER UNIT
2
3
REFERENCE MANUAL
1
OUTDOOR UNIT'S SERVICE MANUAL
Service Ref. Service Manual No.
PUHZ-RP35/50/60/71VHA4
OCH451PUHZ-RP100/125/140VKA
PUHZ-RP100/125/140YKA
PUHZ-HRP71/100VHA
OCH425
PUHZ-HRP71/100VHA2
PUHZ-HRP71/100VHA2R1
PUHZ-HRP100VHA2R2
PUHZ-HRP100/125YHA
PUHZ-HRP100/125YHA2
PUHZ-HRP100/125YHA2R1
PUHZ-W50/85VHA(-BS)
OCH439
PUHZ-W50/85VHAR1(-BS)
PUHZ-W50VHAR2(-BS)
PUHZ-W85VHA2.UK OCH465
PUHZ-W85VHA2-BS.UK
PUHZ-HW112/140YHA(-BS)
OCH439
PUHZ-HW112/140YHA2(-BS)
PUHZ-HW112/140YHA2R1(-BS)
PUHZ-HW112/140YHA2R3(-BS)
PUHZ-HW140VHA(-BS)
PUHZ-HW140VHA2(-BS)
PUHZ-HW140VHA2R1(-BS)
PUHZ-HW140VHA2R2-BS
PUHZ-HW140VHA2R3(-BS)
PUHZ-SW40/45VHA(-BS) OCH525
PUHZ-SW75/100/120VHA(-BS) OCH533
PUHZ-SW100/125YHA(-BS)
PUHZ-SHW80/112VHA OCH526
PUHZ-SWH112/140YHA
OCH531
2
3
SAFETY PRECAUTION
2
Please read the following safety precautions carefully.
WARNING:
Precautions that must be observed to prevent injuries or death. CAUTION:
Precautions that must be observed to prevent damage to unit.
Mitsubishi Electric is not responsible for the failure of locally-supplied and eld-supplied parts.
Be sure to perform periodical maintenance.
Be sure to follow your local regulations.
Be sure to follow the instructions provided in this manual.
•
•
•
WARNING
Mechanical
The cylinder unit and outdoor unit must not be installed, disassembled, relocated, altered or repaired by the user. Ask an authorised installer or technician. If the
unit is installed improperly or modied after installation by the user water leakage, electric shock or re may result.
The outdoor unit should be securely xed to a hard level surface capable of bearing its weight.
The cylinder unit should be positioned on a hard level surface capable of supporting its lled weight to prevent excessive sound or vibration.
Do not position furniture or electrical appliances below the outdoor unit or cylinder unit.
The discharge pipework from the emergency devices of the cylinder unit should be installed according to local law.
Only use accessories and replacement parts authorised by Mitsubishi Electric ask a qualied technician to t the parts.
Electrical
All electrical work should be performed by a qualied technician according to local regulations and the instructions given in this manual.
The units must be powered by a dedicated power supply and the correct voltage and circuit breakers must be used.
Wiring should be in accordance with national wiring regulations. Connections must be made securely and without tension on the terminals.
Earth unit correctly.
General
Keep children and pets away from both the cylinder unit and outdoor unit.
Do not use the hot water produced by the heat pump directly for drinking or cooking. This could cause illness to the user.
Do not stand on the units.
Do not touch switches with wet hands.
Annual maintenance checks on both the cylinder unit and the outdoor unit should be done by qualied person.
Do not place containers with liquids in on top of the cylinder unit. If they leak or spill onto the cylinder unit damage to the unit and/or re could occur.
Do not place any heavy items on top of the cylinder unit.
When installing or relocating, or servicing the cylinder unit, use only the specied refrigerant (R410A) to charge the refrigerant lines. Do not mix it with any other
refrigerant and do not allow air to remain in the lines. If air is mixed with the refrigerant, then it can be the cause of abnormal high pressure in the refrigerant
line, and may result in an explosion and other hazards.
The use of any refrigerant other than that specied for the system will cause mechanical failure or system malfunction or unit breakdown. In the worst case, this
could lead to a serious impediment to securing product safety.
In heating mode, to avoid the heat emitters being damaged by excessively hot water, set the target ow temperature to a minimum of 2ºC below the maximum
allowable temperature of all the heat emitters. For Zone2, set the target ow temperature to a minimum of 5ºC below the maximum allowable ow temperature
of all the heat emitters in Zone2 circuit.
CAUTION
Use clean water that meets local quality standards on the primary circuit.
The outdoor unit should be installed in an area with sufcient airow according to the diagrams in the outdoor unit installation manual.
The cylinder unit should be located inside to minimise heat loss.
Water pipe-runs on the primary circuit between outdoor and indoor unit should be kept to a minimum to reduce heat loss.
Ensure condensate from outdoor unit is piped away from the base to avoid puddles of water.
Remove as much air as possible from the primary and DHW circuits.
Refrigerant leakage may cause suffocation. Provide ventilation in accordance with EN378-1.
Be sure to wrap insulation around the piping. Direct contact with the bare piping may result in burns or frostbite.
Never put batteries in your mouth for any reason to avoid accidental ingestion.
Battery ingestion may cause choking and/or poisoning.
Install the unit on a rigid structure to prevent excessive sound or vibration during operation.
Do not transport the cylinder unit with water inside the DHW tank or coil. This could cause damage to the unit.
If power to the cylinder unit is to be turned off (or system switched off) for a long time, the water should be drained.
If unused for a long period, before operation is resumed, DHW tank should be ushed through with potable water.
Preventative measures should be taken against water hammer, such as installing a Water Hammer Arrestor on the primary water circuit, as directed by the manu-
facturer.
OCH531
4
5
WARNING (SPLIT MODELS ONLY)
Do not discharge refrigerant into the atmosphere if refrigerant leaks during installation, ventilate the room.
Use appropriate tools for high pressure refrigerant.
When pumping down refrigerant , stop the compressor before disconnecting the refrigerant pipes.
During installation securely fasten the refrigerant pipes before starting the compressor.
Check that refrigerant gas does not leak after the completion of installation.
Use R410A refrigerant only. Do not allow air to enter the lines. Failure to observe these instructions will cause mechanical failure, system failure or, in the worst
case, serious breach of product safety.
CAUTION (SPLIT MODELS ONLY)
<Using R410A refrigerant heat pumps>
Use C1220 copper phosphorus, for copper and copper alloy seamless pipes, to connect the refrigerant pipes. Make sure the insides of the pipes are clean and
do not contain any harmful contaminants such as sulfuric compounds, oxidants, debris, or dust. Use pipes with the specied thickness. (Refer to section 4.5. in
the installation manual.) Note the following if reusing existing pipes that carried R22 refrigerant.
- Replace the existing are nuts and are the ared sections again.
- Do not use thin pipes. (Refer to section 4.5 in the installation manual.)
Store the pipes to be used during installation indoors and keep both ends of the pipes sealed until just before brazing. (Leave elbow joints, etc. in their packag-
ing.) If dust, debris, or moisture enters the refrigerant lines, oil deterioration or compressor breakdown may result.
Use ester oil, ether oil, alkylbenzene oil (small amount) as the refrigeration oil applied to the ared sections. If mineral oil is mixed in the refrigeration oil, oil dete-
rioration may result.
Do not use refrigerant other than R410A refrigerant. If another refrigerant is used, the chlorine will cause the oil to deteriorate.
Use the following tools specically designed for use with R410A refrigerant. The following tools are necessary to use R410A refrigerant. Contact your nearest
dealer for any questions.
Tools (for R410A)
Gauge manifold Flare tool
Charge hose Size adjustment gauge
Gas leak detector Vacuum pump adapter
Torque wrench Electronic refrigerant charging scale
Be sure to use the correct tools. If dust, debris, or moisture enters the refrigerant lines, refrigeration oil deterioration may result.
Do not use a charging cylinder, a cylindrical measuring container, when charging R410A refrigerant gas. If the refrigerant gas is transferred to a charging cylinder,
the composition of the refrigerant will change and system efciency will be reduced.
OCH531
Gravimeter
Unit
4
5
[1] Cautions for service
(1) Perform service after recovering the refrigerant left in unit completely.
(2) Do not release refrigerant in the air.
(3) After completing service, charge the cycle with specified amount of refrigerant.
(4) When performing service, install a filter drier simultaneously.
Be sure to use a filter drier for new refrigerant.
[2] Additional refrigerant charge
When charging directly from refrigerant cylinder
· Check that cylinder for R410A on the market is syphon type.
· Charging should be performed with the refrigerant cylinder of syphon stood vertically. (Refrigerant is charged from liquid
phase.)
[3] Service tools
Use the service tools below as exclusive tools for R410A refrigerant.
No. Tool name Specifications
1
Gauge manifold
· Only for R410A
· Use the existing fitting specifications. (UNF1/2)
· Use high-tension side pressure of 5.3 MPa·G or over.
2
Charge hose · Only for R410A
· Use pressure performance of 5.09 MPa·G or over.
3Electronic scale —
4Gas leak detector · Use the detector for R134a, R407C or R410A
5Adaptor for reverse flow check · Attach on vacuum pump.
6Refrigerant charge base —
7
Refrigerant cylinder · Only for R410A ·Top of cylinder (Pink)
· Cylinder with syphon
8Refrigerant recovery equipment —
OCH531
6
7
SPECIFICATIONS
3
Model name EHST20C-
VM6HB EHST20C-
YM9HB EHST20C-
VM6B EHST20C-
YM9B EHST20C-
VM6EB EHST20C-
YM9EB EHST20C-
VM6SB EHPT20X-
VM2HB EHPT20X-
VM6HB EHPT20X-
YM9HB EHPT20X-
VM6B EHPT20X-
YM9B
Nominal domestic hot water volume 200L
Overall unit dimensions 1600 x 595 x 680 mm (Height x Width x Depth)
Weight (empty) 128 kg 128 kg 127 kg 127 kg 122 kg 122 kg 128 kg 113 kg 115 kg 115 kg 114 kg 114 kg
Weight (full) 343 kg 343 kg 342 kg 342 kg 337 kg 337 kg 343 kg 326 kg 328 kg 328 kg 327 kg 327 kg
Plate heat exchanger — — — — —
Unvented expansion vessel
(Primary heating) Nominal volume 12 L — — 12 L
Charge pressure 1 bar — — 1 bar
Safety device Water circuit
(Primary) Control thermistor Heating 1 - 80°C
Pressure relief valve 0.3 MPa (3 bar)
Flow switch Min ow 5.5 l/min
Booster heater Manual reset thermostat 90°C
Thermal Cut-out (for dry run prevention) 121°C
DHW tank Control thermistor 40 - 70°C
Temperature and pressure relief valve 1.0 MPa
(10 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar)
90°C/0.7 MPa
(7 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar) 1.0 MPa
(10 bar)
Primary circuit circulating Pump Grundfos UPM2 25 70 - 180
Connections Water 28 mm compression primary circuit/ 22 mm compression DHW circuit/22 mm compression solar thermal (Ancillary heating) circuit
Refrigerant
(R410A) Liquid 9.52 mm 9.52 mm 9.52 mm 9.52 mm 9.52 mm 9.52 mm 9.52 mm — — — — —
Gas 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm
Target temperature range Flow temperature Heating 25 - 60°C
Cooling —
Room temperature Heating 10 - 30°C
Cooling —
Guaranteed operating range Ambient *1 0 - 35°C ( 80 %RH)
Outdoor
temperature
Heating See outdoor unit spec table.
Cooling —
DHW tank performance *2 Time to raise DHW tank temp 15 - 65°C 21.75 min
Time to reheat 70% of DHW tank to 65°C 16 min
Electrical data Control board Power supply
(Phase, voltage, frequency)
~/N, 230 V, 50 Hz
Breaker (*when powered
from independent source) 10A
Booster heater Power supply
(Phase, voltage, frequency)
~/N, 230 V,
50 Hz 3~, 400 V,
50 Hz ~/N, 230 V,
50 Hz 3~, 400 V,
50 Hz ~/N, 230 V,
50 Hz 3~, 400 V,
50 Hz ~/N, 230 V,
50 Hz ~/N, 230 V,
50 Hz ~/N, 230 V,
50 Hz 3~, 400 V,
50 Hz ~/N, 230 V,
50 Hz
3~, 400 V,
50 Hz
Capacity 2 kW+4 kW 3 kW+6 kW 2 kW+4 kW 3 kW+6 kW 2 kW+4 kW 3 kW+6 kW 2 kW+4 kW 2 kW 2 kW+4 kW 3 kW+6 kW 2 kW+4 kW 3 kW+6 kW
Current 26 A 13 A 26 A 13 A 26 A 13 A 26 A 9 A 26 A 13 A 26 A 13 A
Breaker 32 A 16 A 32 A 16 A 32 A 16 A 32 A 16 A 32 A 16 A 32 A 16 A
Immersion heater
*3 Power supply
(Phase, voltage, frequency)
~/N, 230 V, 50 Hz —~/N, 230 V, 50 Hz —
Capacity 3 kW — 3 kW —
Current 13 A — 13 A —
Breaker 16 A — 16 A —
Solar (ancillary) connection — — — — — — — — — — —
Optional extras
• Wireless Remote Controller PAR-WT50R-E • Remote sensor PAC-SE41TS-E
• Wireless Receiver PAR-WR51R-E • Joint pipe (15.88 → 12.7) PAC-SH50RJ-E
• Immersion heater (1 Ph 3kW) PAC-IH03V-E • Joint pipe (9.52 → 6.35) PAC-SH30RJ-E
• EHPTAccessories for UK PAC-WK01UK-E •Thermistor PAC-TH011-E
•High temperature thermistor PAC-TH011HT-E
*1 The environment must be frost-free.
*2 Tested under BS7206 conditions .
*3 Do not t immersion heaters without thermal cut-out.
OCH531
6
7
PART NAMES AND FUNCTIONS
4
A21
3
4
5
8
B
E
F
J
K
9
10
11
17
12
13
14 15
16
7
18
19
Figure 4-1
<EHST20C-*M*HB/*M*B> (Split model system) Number Component
1 Automatic air vent
2 Pressure relief valve
3Expansion vessel
4 Main controller
5Control and electrical box
7 Immersion heater (Only for EHST20C-*M*HB)
8 DHW tank
93-way valve
10 Water circulation pump
11 Manual air vent
12 Booster heater
13 Drain cock (Booster heater)
14 Strainer valve
15 Flow switch
16 Drain cock (Primary circuit)
17 Drain cock (DHW tank)
18 Plate heat exchanger
19 Manometer
A DHW outlet
BCold water inlet
EInlet from space heating
F Outlet to space heating
JRefrigerant (Gas)
KRefrigerant (Liquid)
21
4
5
8
A
B
E
F
J
K
9
10
11
17
12
13
14 15
16
18
19
<EHST20C-*M*EB>
(Split model system without expansion vessel ) Number Component
1 Automatic air vent
2 Pressure relief valve
4 Main controller
5Control and electrical box
8 DHW tank
93-way valve
10 Water circulation pump
11 Manual air vent
12 Booster heater
13 Drain cock (Booster heater)
14 Strainer valve
15 Flow switch
16 Drain cock (Primary circuit)
17 Drain cock (DHW tank)
18 Plate heat exchanger
19 Manometer
A DHW outlet
BCold water inlet
EInlet from space heating
F Outlet to space heating
JRefrigerant (Gas)
KRefrigerant (Liquid)
Figure 4-2
OCH531
8
9
2
19
3
4
5
8
A
B
E
F
G
H
9
10
11
17
12
13
14 15
16
7
6
1
<EHPT20X-VM2HB> (UK Packaged model system)
Number Component
1 Automatic air vent
2 Pressure relief valve
3Expansion vessel
4 Main controller
5Control and electrical box
6 Temperature and pressure relief valve (not visible)
7 Immersion heater
8 DHW tank
93-way valve
10 Water circulation pump
11 Manual air vent
12 Booster heater
13 Drain cock (Booster heater)
14 Strainer valve
15 Flow switch
16 Drain cock (Primary circuit)
17 Drain cock (DHW tank)
19 Manometer
A DHW outlet
BCold water inlet
EInlet from space heating
F Outlet to space heating
G Inlet from heat pump
H Outlet to heat pump
21
3
4
5
8
A
B
E
F
J
K
9
10
11
17
12
13
14 15
16
18
C
D19
<EHST20C-VM6SB> (Solar split model system) Number Component
1 Automatic air vent
2 Pressure relief valve
3Expansion vessel
4 Main controller
5Control and electrical box
8 DHW tank
93-way valve
10 Water circulation pump
11 Manual air vent
12 Booster heater
13 Drain cock (Booster heater)
14 Strainer valve
15 Flow switch
16 Drain cock (Primary circuit)
17 Drain cock (DHW tank)
18 Plate heat exchanger
19 Manometer
A DHW outlet
BCold water inlet
C Outlet to solar
D Inlet from solar
EInlet from space heating
F Outlet to space heating
JRefrigerant (Gas)
KRefrigerant (Liquid)
Figure 4-3
Figure 4-4
OCH531
8
9
2
19
3
4
5
8
A
B
E
F
G
H
9
10
11
17 12
13
14 15
16
7
1
<EHPT20X-*M*HB/*M*B (except EHPT20X-VM2HB)> (Packaged model system)
Number Component
1 Automatic air vent
2 Pressure relief valve
3Expansion vessel
4 Main controller
5Control and electrical box
7 Immersion heater (Only for EHPT20X-*M*HB)
8 DHW tank
93-way valve
10 Water circulation pump
11 Manual air vent
12 Booster heater
13 Drain cock (Booster heater)
14 Strainer valve
15 Flow switch
16 Drain cock (Primary circuit)
17 Drain cock (DHW tank)
19 Manometer
A DHW outlet
BCold water inlet
EInlet from space heating
F Outlet to space heating
G Inlet from heat pump
H Outlet to heat pump
Figure 4-5
OCH531
10
11
OUTLINES AND DIMENSIONS
5
445
1600
1095
595
G1/2
118
100±20
950
30
156 50
680
1831
Temperature and
pressure relief valve
and its access plate
(EHPT20X-VM2HB)only)
Terminal block
Front panel
5-1. Technical Drawings
Letter Pipe description Connection size/type
A DHW outlet connection 22 mm/Compression
BCold water inlet connection 22 mm/Compression
C/D
Solar (ancillary heat source) connections
22 mm/Compression
ESpace heating return connection 28 mm/Compression
F Space heating ow connection 28 mm/Compression
GFlow from heat pump connection
(No plate heat exchanger) 28 mm/Compression
HReturn to heat pump connection
(No plate heat exchanger) 28 mm/Compression
JRefrigerant (GAS)
(With plate heat exchanger) 15.88 mm/Flare
KRefrigerant (LIQUID)
(With plate heat exchanger) 9.52 mm/Flare
LElectrical cable inlets
—
For inlets and , run low-voltage wires including
external input wires and thermistor wires. For inlets ,
, and , run high-voltage wires including power cable,
indoor-outdoor cable, and external output wires.
*For a wireless receiver (option) cable, use inlet .
<Left side> <Front> <Right side>
L
H / K
G / J F
E
D
C
B
A
63.3
561.7
509.7
491.1
449.7
123
67.8
0
47.1
550.2
541.1
522.8
492.2
470.8
0
<Top>
<Unit: mm>
Main controller
Air vent
Pressure relief valve
a
b b
d
Service access
5-2. Service access diagrams
Service access
Parameter Dimension (mm)
a 300
b 150
c
(distance behind unit not visible
in the right gure)
10
d 500
Sufcient space MUST be left for the provision of discharge pipework as detailed
in National and Local Building Regulations.
The cylinder unit must be located indoors and in a frost-free environment, for
example in a utility room, to minimise heat loss from stored water.
OCH531
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
TH2 Thermistor (Ref. liquid temp.)
ECB2
Earth leakage circuit breaker for immersion heater
THW1 Thermistor (Flow water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW2 Thermistor (Return water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 flow temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 flow temp.)(Option)
3WV 3-way valve THW9 Thermistor (Zone2 return temp.)(Option)
MXV Mixing valve (Field supply)
THWB1
Thermistor (Boiler flow temp.)(Option)
BHT Thermostat for booster heater
THWB2
Thermistor (Boiler return temp.)(Option)
BHF Thermal fuse for booster heater IN1 Room thermostat 1 (Field supply)
BH1 Booster heater 1 IN2 Flow switch 1
BH2 Booster heater 2 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHC2 Contactor for booster heater 2 IN5 Outdoor thermostat (Field supply)
BHCP Contactor for booster heater protection IN6 Room thermostat 2 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater
IN7 Flow switch 3 (Field supply)
IH Immersion heater
FLOW TEMP. CONTROLLER (FTC4)
IHC Contactor for immersion heater
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal Inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>.
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
EHST20C-VM6HB WIRING DIAGRAM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L
(1)
N
(3)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
BLU
BLU
BLU
RED
RED
BLU
BLU/No.3
WHT/No.2
WHT/No.1
BLU/No.4
RED
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF
BH2
24
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
~/N 230V 50Hz
2
2
2
2
1
3
5
7
1
5
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
TBO.2
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
1
3
1
3
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
TBO.1
X9
642
531 A1
A2
Open
Close
N
3
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
2695
2
1TBI.2
1210 148
13
7
11
4
31
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
13
CN21
(YLW)
TH2
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
10
11
6-1. EHST20C-VM6HB
6 WIRING DIAGRAM
OCH531
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
TH2 Thermistor (Ref. liquid temp.)
ECB2
Earth leakage circuit breaker for immersion heater
THW1 Thermistor (Flow water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW2 Thermistor (Return water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 flow temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 flow temp.)(Option)
3WV 3-way valve THW9 Thermistor (Zone2 return temp.)(Option)
MXV Mixing valve (Field supply)
THWB1
Thermistor (Boiler flow temp.)(Option)
BHT Thermostat for booster heater
THWB2
Thermistor (Boiler return temp.)(Option)
BHF Thermal fuse for booster heater IN1 Room thermostat 1 (Field supply)
BH1 Booster heater 1 IN2 Flow switch 1
BH2 Booster heater 2 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHC2 Contactor for booster heater 2 IN5 Outdoor thermostat (Field supply)
BHCP Contactor for booster heater protection IN6 Room thermostat 2 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater
IN7 Flow switch 3 (Field supply)
IH Immersion heater
FLOW TEMP. CONTROLLER (FTC4)
IHC Contactor for immersion heater
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal Inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
EHST20C-YM9HB WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L1
(1) L2
(3) L3
(5)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
WHT
BLK
RED
WHT
BLK
RED
BLU
BLU/No.4
WHT/No.2
WHT/No.1
BLU/No.5
WHT/No.3
BLU/No.6
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF BH2
24 6
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
3~ 400V 50Hz
2
2
2
2
1
3
5
7
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
1
3
1
3
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
X9
642
531 A1
A2
WHT
BLK
RED
3
1
5
TBO.2
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
Open
Close
N
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
295
2
1TBI.2
12
610 148
13
7
11
4
31
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
13
CN21
(YLW)
TH2
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
12
13
6-2. EHST20C-YM9HB
OCH531
EHST20C-VM6B WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
TH2 Thermistor (Ref. liquid temp.)
ECB2
Earth leakage circuit breaker for immersion heater (Option)
THW1 Thermistor (Flow water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW2 Thermistor (Return water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 flow temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 flow temp.)(Option)
3WV 3-way valve THW9 Thermistor (Zone2 return temp.)(Option)
MXV Mixing valve (Field supply)
THWB1
Thermistor (Boiler flow temp.)(Option)
BHT Thermostat for booster heater
THWB2
Thermistor (Boiler return temp.)(Option)
BHF Thermal fuse for booster heater IN1 Room thermostat 1 (Field supply)
BH1 Booster heater 1 IN2 Flow switch 1
BH2 Booster heater 2 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHC2 Contactor for booster heater 2 IN5 Outdoor thermostat (Field supply)
BHCP Contactor for booster heater protection IN6 Room thermostat 2 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater (Option)
IN7 Flow switch 3 (Field supply)
IH Immersion heater (Option)
FLOW TEMP. CONTROLLER (FTC4)
IHC Contactor for immersion heater (Option)
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal Inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L
(1)
N
(3)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
BLU
BLU
BLU
REDRED
BLU
BLU/No.3
WHT/No.2
WHT/No.1
BLU/No.4
RED
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF
BH2
24
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
~/N 230V 50Hz
2
2
2
2
1
3
5
7
1
5
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
TBO.2
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
1
3
1
3
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
TBO.1
X9
642
531 A1
A2
Open
Close
N
3
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
45 953
2 2
1TBI.2
12
610 148
13
7
11
4
31
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
13
CN21
(YLW)
TH2
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
12
13
6-3. EHST20C-VM6B
OCH531
EHST20C-YM9B WIRING DIAGRAM
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
TH2 Thermistor (Ref. liquid temp.)
ECB2
Earth leakage circuit breaker for immersion heater (Option)
THW1 Thermistor (Flow water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW2 Thermistor (Return water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 flow temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 flow temp.)(Option)
3WV 3-way valve THW9 Thermistor (Zone2 return temp.)(Option)
MXV Mixing valve (Field supply)
THWB1
Thermistor (Boiler flow temp.)(Option)
BHT Thermostat for booster heater
THWB2
Thermistor (Boiler return temp.)(Option)
BHF Thermal fuse for booster heater IN1 Room thermostat 1 (Field supply)
BH1 Booster heater 1 IN2 Flow switch 1
BH2 Booster heater 2 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHC2 Contactor for booster heater 2 IN5 Outdoor thermostat (Field supply)
BHCP Contactor for booster heater protection IN6 Room thermostat 2 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater (Option)
IN7 Flow switch 3 (Field supply)
IH Immersion heater (Option)
FLOW TEMP. CONTROLLER (FTC4)
IHC Contactor for immersion heater (Option)
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal Inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
S3
TB1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L1
(1) L2
(3) L3
(5)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
WHT
BLK
RED
WHT
BLK
RED
BLU
BLU/No.4
WHT/No.2
WHT/No.1
BLU/No.5
WHT/No.3
BLU/No.6
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF BH2
24 6
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
3~ 400V 50Hz
2
2
2
2
1
3
5
7
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
1
3
1
3
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
X9
642
531 A1
A2
WHT
BLK
RED
3
1
5
TBO.2
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
Open
Close
N
NL
S3S2S1
NL
S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
2
1TBI.2
12
610 148
13
7
11
9
4
5
3
2
1
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
13
CN21
(YLW)
TH2
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
14
15
6-4. EHST20C-YM9B
OCH531
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L
(1)
N
(3)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
BLU
BLU
BLU
RED
RED
BLU
BLU/No.3
WHT/No.2
WHT/No.1
BLU/No.4
RED
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF
BH2
24
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
~/N 230V 50Hz
2
2
2
2
1
3
5
7
1
5
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
TBO.2
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
1
3
1
3
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
TBO.1
X9
642
531 A1
A2
Open
Close
N
3
EHST20C-VM6EB WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
TH2 Thermistor (Ref. liquid temp.)
ECB2
Earth leakage circuit breaker for immersion heater (Option)
THW1 Thermistor (Flow water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW2 Thermistor (Return water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 flow temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 flow temp.)(Option)
3WV 3-way valve THW9 Thermistor (Zone2 return temp.)(Option)
MXV Mixing valve (Field supply)
THWB1
Thermistor (Boiler flow temp.)(Option)
BHT Thermostat for booster heater
THWB2
Thermistor (Boiler return temp.)(Option)
BHF Thermal fuse for booster heater IN1 Room thermostat 1 (Field supply)
BH1 Booster heater 1 IN2 Flow switch 1
BH2 Booster heater 2 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHC2 Contactor for booster heater 2 IN5 Outdoor thermostat (Field supply)
BHCP Contactor for booster heater protection IN6 Room thermostat 2 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater (Option)
IN7 Flow switch 3 (Field supply)
IH Immersion heater (Option)
FLOW TEMP. CONTROLLER (FTC4)
IHC Contactor for immersion heater (Option)
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal Inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 610
14
8137 119
453
2
1TBI.2
1210 148
13
7
11
9
4
5
3
2
1
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
13
CN21
(YLW)
TH2
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
14
15
6-5. EHST20C-VM6EB
OCH531
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L1
(1) L2
(3) L3
(5)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
WHT
BLK
RED
WHT
BLK
RED
BLU
BLU/No.4
WHT/No.2
WHT/No.1
BLU/No.5
WHT/No.3
BLU/No.6
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF BH2
24 6
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
3~ 400V 50Hz
2
2
2
2
1
3
5
7
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
1
3
1
3
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
X9
642
531 A1
A2
WHT
BLK
RED
3
1
5
TBO.2
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
Open
Close
N
EHST20C-YM9EB WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
TH2 Thermistor (Ref. liquid temp.)
ECB2
Earth leakage circuit breaker for immersion heater (Option)
THW1 Thermistor (Flow water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW2 Thermistor (Return water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 flow temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 flow temp.)(Option)
3WV 3-way valve THW9 Thermistor (Zone2 return temp.)(Option)
MXV Mixing valve (Field supply)
THWB1
Thermistor (Boiler flow temp.)(Option)
BHT Thermostat for booster heater
THWB2
Thermistor (Boiler return temp.)(Option)
BHF Thermal fuse for booster heater IN1 Room thermostat 1 (Field supply)
BH1 Booster heater 1 IN2 Flow switch 1
BH2 Booster heater 2 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHC2 Contactor for booster heater 2 IN5 Outdoor thermostat (Field supply)
BHCP Contactor for booster heater protection IN6 Room thermostat 2 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater (Option)
IN7 Flow switch 3 (Field supply)
IH Immersion heater
(Option)
FLOW TEMP. CONTROLLER (FTC4)
IHC Contactor for immersion heater
(Option)
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal Inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
2
1TBI.2
12
610 148
13
7
11
9
4
5
3
2
1
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
13
CN21
(YLW)
TH2
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
16
17
6-6. EHST20C-YM9EB
OCH531
EHST20C-VM6SB WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
TH2 Thermistor (Ref. liquid temp.)
ECB2
Earth leakage circuit breaker for immersion heater (Option)
THW1 Thermistor (Flow water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW2 Thermistor (Return water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 flow temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 flow temp.)(Option)
3WV 3-way valve THW9 Thermistor (Zone2 return temp.)(Option)
MXV Mixing valve (Field supply)
THWB1
Thermistor (Boiler flow temp.)(Option)
BHT Thermostat for booster heater
THWB2
Thermistor (Boiler return temp.)(Option)
BHF Thermal fuse for booster heater IN1 Room thermostat 1 (Field supply)
BH1 Booster heater 1 IN2 Flow switch 1
BH2 Booster heater 2 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHC2 Contactor for booster heater 2 IN5 Outdoor thermostat (Field supply)
BHCP Contactor for booster heater protection IN6 Room thermostat 2 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater (Option)
IN7 Flow switch 3 (Field supply)
IH Immersion heater
(Option)
FLOW TEMP. CONTROLLER (FTC4)
IHC Contactor for immersion heater
(Option)
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal Inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L
(1)
N
(3)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
BLU
BLU
BLU
REDRED
BLU
BLU/No.3
WHT/No.2
WHT/No.1
BLU/No.4
RED
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF
BH2
24
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
~/N 230V 50Hz
2
2
2
2
1
3
5
7
1
5
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
TBO.2
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
1
3
1
3
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
TBO.1
X9
642
531 A1
A2
Open
Close
N
3
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
2
1TBI.2
12
610 148
13
7
11
9
4
5
3
2
1
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
13
CN21
(YLW)
TH2
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
16
17
6-7. EHST20C-VM6SB
OCH531
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
THW1 Thermistor (Flow water temp.)
ECB2
Earth leakage circuit breaker for immersion heater
THW2 Thermistor (Return water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW5 Thermistor (DHW tank water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW6 Thermistor (Zone 1 flow temp.)(Option)
THW7 Thermistor (Zone 1 return temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW8 Thermistor (Zone 2 flow temp.)(Option)
THW9 Thermistor (Zone 2 return temp.)(Option)
3WV 3-way valve
THWB1
Thermistor (Boiler flow temp.)(Option)
MXV Mixing valve (Field supply)
THWB2
Thermistor (Boiler return temp.)(Option)
BHT Thermostat for booster heater IN1 Room thermostat 1 (Field supply)
BHF Thermal fuse for booster heater IN2 Flow switch 1
BH1 Booster heater 1 IN3 Flow switch 2 (Field supply)
BHC1 Contactor for booster heater 1 IN4 Demand control (Field supply)
BHCP Contactor for booster heater protection IN5 Outdoor thermostat (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater
IN6 Room thermostat 2 (Field supply)
IH Immersion heater IN7 Flow switch 3 (Field supply)
IHC Contactor for immersion heater
FLOW TEMP. CONTROLLER (FTC4)
TBO.1~2
Terminal block <Outputs>
TBI.1~2
Terminal block <Signal inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
2
1TBI.2
12
6
10 148
13
7
11
9
4
5
3
2
1
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281
TBI.2
13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2
ECB1
L
(1)
N
(3)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
BLU
BLU
RED
BLU
WHT/No.2
WHT/No.1
RED
RED
VLT
VLT
GRY
GRY
ORN
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF
24
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
~/N 230V 50Hz
2
2
2
1
3
5
7
1
5
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
TBO.2
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
1
3
1
3
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
TBO.1
X9
642
531 A1
A2
Open
Close
N
3
EHPT20X-VM2HB WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
18
19
6-8. EHPT20X-VM2HB
OCH531
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
THW1 Thermistor (Flow water temp.)
ECB2
Earth leakage circuit breaker for immersion heater
THW2 Thermistor (Return water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW5 Thermistor (DHW tank water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW6 Thermistor (Zone 1 flow temp.)(Option)
THW7 Thermistor (Zone 1 return temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW8 Thermistor (Zone 2 flow temp.)(Option)
THW9 Thermistor (Zone 2 return temp.)(Option)
3WV 3-way valve
THWB1
Thermistor (Boiler flow temp.)(Option)
MXV Mixing valve (Field supply)
THWB2
Thermistor (Boiler return temp.)(Option)
BHT Thermostat for booster heater IN1 Room thermostat 1 (Field supply)
BHF Thermal fuse for booster heater IN2 Flow switch 1
BH1 Booster heater 1 IN3 Flow switch 2 (Field supply)
BH2 Booster heater 2 IN4 Demand control (Field supply)
BHC1 Contactor for booster heater 1 IN5 Outdoor thermostat (Field supply)
BHC2 Contactor for booster heater 2 IN6 Room thermostat 2 (Field supply)
BHCP Contactor for booster heater protection IN7 Flow switch 3 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater
FLOW TEMP. CONTROLLER (FTC4)
IH Immersion heater
TBO.1~2
Terminal block <Outputs>
IHC Contactor for immersion heater
TBI.1~2
Terminal block <Signal inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L
(1)
N
(3)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
BLU
BLU
BLU
REDRED
BLU
BLU/No.3
WHT/No.2
WHT/No.1
BLU/No.4
RED
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF
BH2
24
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
~/N 230V 50Hz
2
2
2
2
1
3
5
7
1
5
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
TBO.2
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
1
3
1
3
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
TBO.1
X9
642
531 A1
A2
Open
Close
N
3
EHPT20X-VM6HB WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
2
1TBI.2
12
610 148
13
7
11
9
4
5
3
2
1
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281 TBI.2 13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
18
19
6-9. EHPT20X-VM6HB
OCH531
Symbol Name Symbol Name
TB1
Terminal block <Power supply, Outdoor unit>
TH1 Thermistor (Room temp.)(Option)
ECB1
Earth leakage circuit breaker for booster heater
THW1 Thermistor (Flow water temp.)
ECB2
Earth leakage circuit breaker for immersion heater
THW2 Thermistor (Return water temp.)
MP1
Water circulation pump1(Space heating & DHW)
THW5 Thermistor (DHW tank water temp.)
MP2 Water circulation pump2
(Space heating for Zone1)(Field supply) THW6 Thermistor (Zone 1 flow temp.)(Option)
THW7 Thermistor (Zone 1 return temp.)(Option)
MP3 Water circulation pump3
(Space heating for Zone2)(Field supply) THW8 Thermistor (Zone 2 flow temp.)(Option)
THW9 Thermistor (Zone 2 return temp.)(Option)
3WV 3-way valve
THWB1
Thermistor (Boiler flow temp.)(Option)
MXV Mixing valve (Field supply)
THWB2
Thermistor (Boiler return temp.)(Option)
BHT Thermostat for booster heater IN1 Room thermostat 1 (Field supply)
BHF Thermal fuse for booster heater IN2 Flow switch 1
BH1 Booster heater 1 IN3 Flow switch 2 (Field supply)
BH2 Booster heater 2 IN4 Demand control (Field supply)
BHC1 Contactor for booster heater 1 IN5 Outdoor thermostat (Field supply)
BHC2 Contactor for booster heater 2 IN6 Room thermostat 2 (Field supply)
BHCP Contactor for booster heater protection IN7 Flow switch 3 (Field supply)
IHT
Thermostat (fixed temp.) for immersion heater
FLOW TEMP. CONTROLLER (FTC4)
IH Immersion heater
TBO.1~2
Terminal block <Outputs>
IHC Contactor for immersion heater
TBI.1~2
Terminal block <Signal inputs, Thermistor>
F1~F2
Fuse (T6.3AL250V)
SW1~4
Dip switch *See <6-13 Dip switch setting>
X1~X12
Relay
LED1 Power supply (FTC4)
LED2 Power supply (Main controller)
LED3 Communication (FTC4-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM
Pump speed control signal for MP1
CN108
SD card connector
NL
S3S2S1
NL
S3S2S1
Figure 1
To outdoor
unit
TB1
ORN ORN
YLW
BLK BLK
YLW
GRN/YLW
To outdoor
unit
Power supply
~/N 230V 50Hz
TB1
ORN
BLU
RED
BLU
RED
YLW
GRN/YLW
1
3
CN3C
(BLU)
5
3
1
1
3
5
3
1
CN01
(BLK)
ORN
BRN
CN3C
(BLU)
CN01
(BLK)
ORN
ORN
BRN
YLW
Cylinder unit powered
by independent source.
Cylinder unit powered
via outdoor unit
CIRCUIT
BREAKER
TBO.1
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBO.2
FTC4
3
9
5
1
7
2
8
4
6
11 10
12
13 14
TBI.1
126 10
14
8137 119
453
2
1TBI.2
12
6
10 148
13
7
11
9
4
5
3
2
1
1 3
CNP1(WHT)
1
5CNV1
(WHT) 1
3
CN3C
(BLU)
5
3
1
CN01
(BLK)
1 8
SW3 1 8
SW1
LED1
LED3
1
1
8
6
SW2
SW4
TBI.1 13
10 12 14
11
7
4 6
5 9
3
281
TBI.2
13
10 12 14
11
7
4 6
5 9
3
281
12
CN20
(RED)
TH1
14
THW1
1213
IN2
IN7
IN6
IN5
IN4
IN3
IN1
t
°
t
°
THWB2
THWB1
THW8
t
°
THW6
t
°
THW7
t
°
THW9
t
°
Main
controller
12
THW2
THW5 CNW5
(WHT)
CNW12
(RED)
t
°
t
°
t
°
t
°
1
3
1
7
CN2F
(YLW) CN20
(RED) CN21
(YLW)
CNW12
(RED)
CNW5
(WHT)
1
2
1
2
CN108
1
3
13 13
CNBH
(WHT)
CNBHT
(BLK)
13
CNIH
(ORN)
CNBC
(GRY)
1
7
LED4
LED2
1
2
CN22
(BLU)
CNPWM
(WHT)
1
3
5
1
Wireless receiver
(Option)
CNRF
(WHT)
5
1
CN105
(RED)
CN2F
(YLW)
CN22
(BLU)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2 2
2 2 2
ECB1
L1
(1) L2
(3) L3
(5)
L
(1)
N
(3)
ECB2
BHCP
ORN
RED
BLU
WHT
BLK
RED
WHT
BLK
RED
BLU
BLU/No.4
WHT/No.2
WHT/No.1
BLU/No.5
WHT/No.3
BLU/No.6
RED
VLT
VLT
PNK
PNK
GRY
GRY
ORN
BHC2
IHC BHC1
BHT
IHT
IH
642
531 A1
A2
642
531 A1
A2
642
531 A1
A2
BH1
A B
BHF BH2
24 6
24
Power supply
to Immersion heater
~/N 230V 50Hz
Power supply
to Booster heater
3~ 400V 50Hz
2
2
2
2
1
3
5
7
X1
X2
X3
X4
X5A
X12
X11
X6
X8
X7
5
3
1
F1
F2
CN01
(BLK)
Signal
output
(Error)
Signal
output
(Defrost)
Signal
output
(Booster
heater2+)
1
3
1
3
CNIH
(ORN)
21
3CNBHT(BLK)
X5B
X10
CNBC
(GRY)
CNBH
(WHT)
X9
642
531 A1
A2
WHT
BLK
RED
3
1
5
TBO.2
3WV
M
1
~
MXV
M
1
~
M
1
~
MP2
M
1
~
MP3
MP1
M
1
~
1
3
CNP1
(WHT)
Signal
output
(Boiler)
CNV1
(WHT)
1
3
CNPWM
(WHT)
Open
Close
N
EHPT20X-YM9HB WIRING DIAGRAM
Table 1 Signal Inputs
Name
Terminal block Connector
Item OFF (Open) ON (Short)
IN1 TBI.1 1-2
— Room thermostat 1 input
Refer to SW2-1 in <6-13Dip switch setting>
IN2 TBI.1 3-4 CN2F
Flow switch 1 input
Refer to SW2-2 in <6-13Dip switch setting>
IN3 TBI.1 5-6
— Flow switch 2 input (Zone1)
Refer to SW3-2 in <6-13Dip switch setting>
IN4 TBI.1 7-8
— Demand control input
Normal
Heat source OFF/Boiler operation *2
IN5 TBI.1 9-10
— Outdoor thermostat input *1
Standard operation
Heater operation/Boiler operation *2
IN6 TBI.1 11-12
— Room thermostat 2 input
Refer to SW3-1 in <6-13Dip switch setting>
IN7 TBI.1 13-14
— Flow switch 3 input (Zone2)
Refer to SW3-3 in <6-13Dip switch setting>
*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and
related parts may be reduced.
*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External/input setting“
screen in the service menu.
Table 2 Outputs
Name
Terminal block Connector
Item OFF ON
OUT1
TBO.1 3-4
CNP1
Water circulation pump 1 output (Space heating & DHW) OFF ON
OUT2
TBO.1 5-6
—
Water circulation pump 2 output (Space heating for Zone1) OFF ON
OUT3
TBO.1 7-8
—
Water circulation pump 3 output (Space heating for Zone2) OFF ON
OUT4
TBO.1 9-11
CNV1
3-way valve output Heating DHW
OUT5
TBO.1 12-13
—
Mixing valve output Stop Close
TBO.1 13-14 Stop Open
OUT6
—
CNBH 1-3
Booster heater 1 output OFF ON
OUT7
—
CNBH 5-7
Booster heater 2 output OFF ON
OUT8
TBO.2 11-12
—
Booster heater 2+ output OFF ON
OUT9
TBO.2 9-10
CNIH
Immersion heater output OFF ON
OUT10
TBO.1 1-2
—
Boiler output OFF ON
OUT11
TBO.2 1-2
—
Error output Normal Error
OUT12
TBO.2 3-4
—
Defrost output Normal Defrost
1. Symbols used in wiring diagram are,
: connector, : terminal block.
2. Indoor unit and outdoor unit connecting wires
have polarities, make sure to match terminal numbers
(S1, S2, S3) for correct wirings,
3. Since the outdoor unit side electric wiring may change,
be sure to check the outdoor unit electric wiring
diagram for servicing.
4. This diagram shows the wiring of indoor unit and
outdoor unit connecting wires (specification of 230V),
adopting superimposed system of power and signal.
When work to supply power separately to indoor
unit and outdoor unit was applied, refer to Figure 1.
20
21
6-10. EHPT20X-YM9HB
OCH531
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