Mitsubishi Electric EHST20C-VM6HA User manual

SERVICE MANUAL
CYLINDER UNIT
No. OCH507
CONTENTS
1. REFERENCE MANUAL................................... 2
2. SAFETY PRECAUTION................................... 3
3. SPECIFICATIONS............................................ 7
4. PART NAMES AND FUNCTIONS .................. 8
5. OUTLINES AND DIMENSIONS..................... 10
6. WIRING DIAGRAM.........................................11
7. FIELD WIRING............................................... 21
8. WATER SYSTEM DIAGRAM......................... 25
9. CONTROLS ................................................... 28
10. TROUBLESHOOTING................................... 43
11. DISASSEMBLY PROCEDURE...................... 56
12. SUPPLEMENTARY INFORMATION ............. 72
13. SERVICE AND MAINTENANCE ................... 73
July 2011
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 (OCB507)
[Model name]
EHST20C-VM6HA
EHST20C-YM9HA
EHST20C-VM6A
EHST20C-YM9A
EHST20C-VM6SA
EHPT20X-VM2HA
EHPT20X-VM6HA
EHPT20X-YM9HA
EHPT20X-VM6A
EHPT20X-YM9A
[Service Ref.]
EHST20C-VM6HA.UK
EHST20C-YM9HA.UK
EHST20C-VM6A.UK
EHST20C-YM9A.UK
EHST20C-VM6SA.UK
EHPT20X-VM2HA.UK
EHPT20X-VM6HA.UK
EHPT20X-YM9HA.UK
EHPT20X-VM6A.UK
EHPT20X-YM9A.UK
CYLINDER UNIT

2
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
OCH439
PUHZ-W50/85VHA-BS
PUHZ-W85VHAR1
PUHZ-W85VHAR1-BS
PUHZ-W85VHA2.UK OCH465
PUHZ-W85VHA2-BS.UK
PUHZ-HW112/140YHA
OCH439
PUHZ-HW112/140YHA-BS
PUHZ-HW112/140YHA2
PUHZ-HW112/140YHA2-BS
PUHZ-HW140VHA
PUHZ-HW140VHA-BS
PUHZ-HW140VHA2
PUHZ-HW140VHA2-BS
PUHZ-HW140VHA2R1-BS

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.
This installation manual along with the user manual should be left with the product after installation for future reference.
Mitsubishi Electric is not responsible for the failure of locally or 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 units 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 modied 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 vertical 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/safety devices of the cylinder unit should be installed according to local law.
Only use accessories and replacement parts authorised by Mitsubishi Electric and employ a qualied technician to t the parts.
Electrical
All electrical work should be performed by a qualied 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 units.
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 qualied person.
Do not place items containing liquid 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 specied 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 specied 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.
CAUTION
Use clean water that meets local quality standards on the primary circuit.
The outdoor unit should be installed in an area with sufcient airow 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 water circuit.
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.
If power to the cylinder unit is to be turned off (or system switched off) for a long time, the water should be drained.
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.

4
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 specied thickness. Note the following if reus-
ing existing pipes that carried R22 refrigerant.
- Replace the existing are nuts and are the ared sections again.
- Do not use thin pipes.
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 specically 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. If a charging cylinder is used, the composition of the refrigerant will change and system efciency will be reduced.
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.

5
Cautions for units utilizing refrigerant R410A
CAUTIONS RELATED TO NEW REFRIGERANT
Use new refrigerant pipes.
If using the existing R22, be careful of the followings.
· For RP100, 125 and 140, be sure to perform replacement
operation before test run.
· Change flare nut to the one provided with this product.
Use a newly flared pipe.
· Avoid using thin pipes.
Charge refrigerant from liquid phase of gas
cylinder.
If the refrigerant is charged from gas phase, composition
change may occur in refrigerant and the efficiency will be
lowered.
Only use R410A refrigerant.
If other refrigerant (R22 etc.) is used, chlorine in refrige-
rant can cause deterioration of refrigerant oil etc.
Use a vacuum pump with a reverse flow check
valve.
Vacuum pump oil may flow back into refrigerant cycle and
that can cause deterioration of refrigerant oil etc.
Use the following tools specifically designed for
use with R410A refrigerant.
The following tools are necessary to use R410A refrigerant.
Handle tools with care.
If dirt, dust or moisture enters into refrigerant cycle, that can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refrigera-
nt will change and the efficiency will be lowered.
Flare tool
Electronic refrigerant
charging scale
Vacuum pump adaptor
Size adjustment gauge
Gauge manifold
Torque wrench
Gas leak detector
Charge hose
Tools for R410A
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil etc.
If dirt, dust or moisture enters into refrigerant cycle, it can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
If large amounts of mineral oil enters, it can cause deterio-
ration of refrigerant oil etc.
The refrigerant oil applied to flare and flange
connections must be ester oil, ether oil or
alkylbenzene oil in a small amount.
Store the piping to be used indoors during
installation, and both ends of the piping sealed
until just before brazing. (Leave elbow joints, etc.
in their packaging.)
Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.
Make sure that the inside and outside of refrige-
rant piping is clean and it has no contaminants
such as sulfur, oxides, dirt, shaving particles, etc,
which are hazard to refrigerant cycle.
In addition, use pipes with specified thickness.
Use the specified refrigerant only.
Never use any refrigerant other than that specified.
Doing so may cause a burst, an explosion, or fire when the
unit is being used, serviced, or disposed of.
Correct refrigerant is specified in the manuals and on the
spec labels provided with our products.
We will not be held responsible for mechanical failure,
system malfunction, unit breakdown or accidents caused
by failure to follow the instructions.

Gravimeter
Unit
6
[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 cylinder
· Check that cylinder for R410A on the market is syphon type.
· Charging should be performed with the 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 —

7
SPECIFICATIONS
3
Product specication
Model name EHST20C-
VM6HA EHST20C-
YM9HA EHST20C-
VM6A EHST20C-
YM9A EHST20C-
VM6SA EHPT20X-
VM2HA EHPT20X-
VM6HA EHPT20X-
YM9HA EHPT20X-
VM6A EHPT20X-
YM9A
Nominal domestic hot water volume 200L Overall unit dimensions 1600 x 595 x 680 mm (Height x Width x Depth) Weight (empty) 131 kg 131 kg 130 kg 130 kg 131 kg 119 kg 119 kg 119 kg 118 kg 118 kg Weight (full) 346 kg 346 kg 345 kg 345 kg 346 kg 332 kg 332 kg 332 kg 331 kg 331 kg Plate heat exchanger Unvented expansion vessel (Primary heating) Nominal volume 12 L
Charge pressure 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 Control thermistor 80°C
Manual reset thermostat 90°C Thermal Cut Off (for dry run prevention) 121°C
DHW tank Control thermistor 40 - 70°C
Temp & 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)
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 UPSO 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 —————
Gas 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm
Operating ambient condition 0 (*1) - 35°C ( 80 % RH) Tank performance *2 Time to raise DHW tank temp 15 - 65°C 23 min
Time to reheat 70% of DHW tank to 65°C 20.5 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 ~/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 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 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
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-WT40R-E • Remote sensor PAC-SE41TS-E
• Wireless Receiver PAR-WR41R-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
*1 The environment must be frost-free. *2 Tested under BS7206 conditions . *3 Do not t immersion heaters without thermal cutout.

21
3
4
5
8
A
B
E
F
J
K
9
10
11
17
12
13
14 15
16
7
18
19
21
3
4
5
8
A
B
E
F
J
K
9
10
11
17
12
13
14 15
16
18
C
D19
8
PART NAMES AND FUNCTIONS
4
Figure 4-1
Figure 4-2
<EHST20C-VM6SA> (Solar split model system)
<EHST20C-*M*HA/*M*A> (Split model system) Number Component
1 Automatic air vent
2 Pressure relief valve
3Expansion vessel
4 Main controller
5Control and electrical box
7Immersion heater (Only for EHST20C-*M*HA)
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
FOutlet to space heating
JRefrigerant (Gas)
KRefrigerant (Liquid)
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
FOutlet to space heating
JRefrigerant (Gas)
KRefrigerant (Liquid)

2
19
3
4
5
8
A
B
E
F
G
H
9
10
11
17 12
13
14 15
16
7
1
2
19
3
4
5
8
A
B
E
F
G
H
9
10
11
17
12
13
14 15
16
7
6
1
9
Figure 4-3
Figure 4-4
<EHPT20X-VM2HA> (UK Packaged model system)
Number Component
1 Automatic air vent
2 Pressure relief valve
3Expansion vessel
4 Main controller
5Control and electrical box
6Temperature 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
FOutlet to space heating
G Inlet from heat pump
H Outlet to heat pump
<EHPT20X-*M*HA/*M*A (except EHPT20X-VM2HA)> (Packaged model system)
Number Component
1 Automatic air vent
2 Pressure relief valve
3Expansion vessel
4 Main controller
5Control and electrical box
7Immersion heater (Only for EHPT20X-*M*HA)
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
FOutlet to space heating
G Inlet from heat pump
H Outlet to heat pump

1831
Main controller
Terminal block
Front panel
Temperature and
pressure relief valve
and its access plate
(EXPT20X-VM2HA only)
680 595
445
1600
Pressure relief valve
G1/2
Air vent
100±20
79
156 50
950
1095
30
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
a
b b
d
10
OUTLINES AND DIMENSIONS
5
5-1. Technical Drawings
Service access
5-2. Service access diagrams
Service access
Parameter Dimension (mm)
a 300
b 150
c (distance behind unit not visible
in the gure on the right)
10
d 500
Sufficient 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.
(Unit: mm)
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) connection 22 mm/Compression
ESpace heating return connection 28 mm/Compression
FSpace 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
L Electrical cable inlets
—
* The leftmost hole is for
wireless receiver (option)
(PAR-WR41R-E)
<Left side> <Front> <Right side>
<Top>