Danfoss DHP-AQ Mini Operating instructions

Service instructions
DHP-AQ
VMGFJ102

If these instructions are not followed during installation and
service, Danfoss A/Sliability according to the applicable warranty
is not binding. Danfoss A/S retains the right to make changes to
components and specifications without prior notice.
© 2011Copyright Danfoss A/S.
The Swedish language is used for the original instructions. Other
languages are a translation of original instructions.
(Directive 2006/42/EG)

Contents
1 About documents and decals ...................................................... 3
1.1 Introduction .................................................................................... 3
1.2 Symbols in documents ................................................................ 3
1.3 Symbols on decals ........................................................................ 3
1.4 Terminology .................................................................................... 5
2 Important information .................................................................... 6
2.1 General safety precautions ........................................................ 6
2.2 Refrigerant ....................................................................................... 6
2.3 Electrical connection .................................................................... 7
2.4 Important information ................................................................ 7
2.5 Commissioning .............................................................................. 8
3 Troubleshooting ................................................................................ 9
3.1 Alarm ................................................................................................. 9
3.2 Components ................................................................................. 10
3.3 Measurement points ................................................................. 11
3.4 Check points ................................................................................. 14
3.5 Operational problems ............................................................... 14
VMGFJ102 – 1

1 About documents and decals
1.1 Introduction
The following documents are available for this product:
•Installation instructions containing information to install and commission a heat pump installation, and infor-
mation about the heat pump’s function, accessories and technical data. Supplied with the heat pump on deliv-
ery.
•Service instructions that contain information about fault tracing. The service instructions are available for
download as below.
•The electrical instructions that contain the wiring diagram for the heat pump intended for fault tracing and
service. The electrical instructions are available for download as below.
•The maintenance instructions must handed over and gone through with the end customer. Supplied with the
heat pump on delivery.
•Country specific instructions and forms are available where relevant. Supplied with the heat pump on delivery.
•Sheet with adhesive decals that will be used as translation for the existing English language type plates.
The Service instructions and Electrical instructions are available for download here:
www.documentation.heatpump.danfoss.com
1.2 Symbols in documents
The instructions contain different warning symbols, which, together with text, indicate to the user that there are
risks involved with actions to be taken.
The symbols are displayed to the left of the text and three different symbols are used to indicate the degree of
danger:
DANGER! Indicates an immediate danger that leads to fatal or serious injury if necessary measures are not
taken.
Warning! Risk of personal injury! Indicates a possible danger that can lead to fatal or serious injury if
necessary measures are not taken.
Caution! Risk of installation damage. Indicates a possible hazard that can lead to item damage if necessary
measures are not taken.
A fourth symbol is used to give practical information or tips on how to perform a procedure.
Note! Information regarding making the handling of the installation easier or a possible operational
technical disadvantage.
1.3 Symbols on decals
The following symbols can occur on decals on the different parts of the heat pump. Which symbols are used
depends on the heat pump model.
Service instructions VMGFJ102 – 3

Warning symbols
!
Warning, danger!
!
Read the documentation provided.
Read the documentation provided.
Warning, hazardous electrical voltage!
Warning, hot surfaces!
Warning, moving parts!
Warning, risk of crushing injury!
Electrical components
Component, normal Component, accessory
3 Outdoor unit 362 Shunt valve
50 Outdoor sensor 363 Exchange valve hot water
54 Hot water sensor 365 Supply line sensor
55 Sensor hot-water top 366 Return line sensor
71 Flow sensor 406 Room sensor
304 Circulation pump 408 EVU
353 Drip tray 417 Defrost sensor
Example:
406
Room sensor
4 – Service instructions VMGFJ102

Pipe connections
Bleeding
Defrosting tank
Expansion tank with safety valve, brine
Brine
Temperature and pressure relief valve
Tap water
Outdoor unit
Water heater
Heating system
1.4 Terminology
Term Meaning
Heating system/Heat transfer fluid
circuit The circuit that generates heat to the property or to the water heater.
Supply line The heating system’s supply line with flow direction from the heat pump to radiators/
under floor heating or water heater.
Return line The heating system’s return line with flow direction from radiators/under floor heating
or water heater to the heat pump.
Circulation pump Circulation pump for heating system.
Refrigerant circuit The energy carrying circuit between the outdoor air and heating system.
Refrigerant The gas/liquid that circulates in the refrigerant circuit.
Service instructions VMGFJ102 – 5

2 Important information
2.1 General safety precautions
Warning! Risk of personal injury! Children are not permitted to play with the product.
Caution! The heat pump must be installed by authorised installation engineers and the installation must
follow the applicable local rules and regulations as well as these installation instructions.
Caution! This product is not intended for persons (including children) with reduced physical, sensory or
psychological capacity, or who do not have knowledge or experience, unless supervised or they have
received instructions on how the apparatus functions from a safety qualified person.
Caution! When cooling it is important to limit the lowest flow line temperature to prevent condensation.
2.2 Refrigerant
2.2.1 Fire risk
The refrigerant is not combustible or explosive in normal conditions.
2.2.2 Toxicity
In normal use and normal conditions the refrigerant has low toxicity. However, although the toxicity of the refrig-
erant is low, it can cause injury (or be highly dangerous) in abnormal circumstances or where deliberately abused.
Warning! Risk of personal injury! Spaces in which heavy vapour can collect below the level of the air must
be well ventilated.
Refrigerant vapour is heavier than air and, in enclosed spaces below the level of a door for example, and in the
event of leakage, concentrations can arise with a resultant risk of suffocation due to a lack of oxygen.
Warning! Risk of personal injury! Refrigerant exposed to a naked flame creates a poisonous irritating gas.
This gas can be detected by its odour even at concentrations below its permitted levels. Evacuate the area
until it has been sufficiently ventilated.
2.2.3 Work on the refrigerant circuit
Caution! Work on the refrigerant circuit must only be carried out by a certified engineer!
Caution! When repairing the refrigerant circuit, the refrigerant must not be released from the heat pump -
it must dealt with in the appropriate way.
6 – Service instructions VMGFJ102

Refilling must only be carried out using new refrigerant (for the amount and type of refrigerant see manufacturer’s
plate) through the service valves.
Caution! All warranties from Danfoss are void if, when filling with refrigerant other than Danfoss A/S
specified refrigerant, if there has not been written notification that the new refrigerant is an approved
replacement refrigerant together with other remedies.
2.2.4 Scrapping
Caution! When the heat pump is to be scrapped the refrigerant must be extracted for disposal. Local rules
and regulations related to the disposal of refrigerant must be followed.
2.3 Electrical connection
DANGER! Hazardous electrical voltage! The terminal blocks are live and can be highly dangerous due to
the risk of electric shock. All power supplies must be isolated before electrical installation is started. The
heat pump is connected internally at the factory, for this reason electrical installation consists mainly of
the connection of the power supply.
Warning! Electrical installation may only be carried out by an authorised electrician and must follow
applicable local and national regulations.
Warning! The electrical installation must be carried out using permanently routed cables. It must be
possible to isolate the power supply using a multi-pole circuit breaker with a minimum contact gap of 3
mm.
2.4 Important information
Caution! A normal heating system always contains a certain amount of corrosion particulates (rust) and
sludge products from calcium oxide. This comes from acid that is naturally occurring in the fresh water
that the system is filled with. It is not good practice to have to fill the heating system regularly which is
why any leakage in the heating system should be repaired immediately. Normal filling should occur only
once or twice a year. The water in the heating system should be as clean as possible, always position the
dirt filter on the return line from the heating system to the heat pump, as close to the heat pump as
possible.
Caution! Hard water; Normally it is not a problem installing a heat pump in areas with hard water because
the normal operating temperature for the hot water does not exceed 60°C. In areas where there are
exceptional prevailing conditions with the water one can install a softening filter, which softens the water,
cleans any impurities and prevents the build up of calcification.
Service instructions VMGFJ102 – 7

2.5 Commissioning
Caution! The installation may only be commissioned if the heating system is filled and bled. Otherwise the
circulation pump can be damaged.
Caution! If the installation is only to operate using an auxiliary heater during the installation, ensure that
the heating system is filled and bled and that the compressor cannot be started. This is carried out by
setting the operating mode to AUX. HEATER.
8 – Service instructions VMGFJ102

3 Troubleshooting
3.1 Alarm
In event of alarm this is indicated in the display with the text ALARM and an alarm message, see following table.
For alarms that are not reset automatically acknowledgement is required. Acknowledge the alarm by setting the
heat pump to operating mode OFF and then back to the desired operating mode.
Message Meaning
MOTOR P COMP.ERROR The compressor motor protection has deployed.
MOTOR P FAN ERROR The fan motor protection has deployed.
EL. HEATER ERROR The electrical heater overheating protection has deployed.
HEAT / PRESSURE ERROR The expected pressure and temperature change in the refrigerant circuit has
not happened in the correct way at compressor start.
LOW PRESSURE ERROR Evaporation pressure has fallen too low.
LOW PRESSURE TRANSDUCER Fault in low pressure transmitter alternatively cable fault.
HIGH PRESSURE ERROR High pressure switch has deployed.
LOW HEAT CIR. FLOW The flow sensor has registered too low a flow.
MAX TEMP ELEC. HW Too high temperature in heat pump junction box/electrical cabinet.
NO. OF TRIES X/5
(where X=1…5) Circulation pump is jammed. Start attempt made.
HEATING CIRC. PUMP Circulation pump is jammed.
HEATING SYSTEM PUMP Circulation pump is jammed.
OUTDOOR SENSOR Sensor fault alternatively cable fault.
DEFROST SENSOR Sensor fault alternatively cable fault. Defrost sensor.
SUPPLY LINE SENSOR Sensor fault alternatively cable fault. Supply line sensor.
SYSTEM SUPPLY LINE SENSOR Sensor fault alternatively cable fault. System supply line sensor.
RETURN LINE SENSOR Sensor fault alternatively cable fault. Return line sensor.
HIGH RETURN LINE TEMP Return line temperature too high
BUFFER TANK SENSOR Sensor fault alternatively cable fault.
HGW SENSOR Sensor fault alternatively cable fault.
HOT WATER SENSOR Sensor fault alternatively cable fault (the lower sensor, Start sensor).
HOT WATER TOP Sensor fault alternatively cable fault.
FAILSAFE MODE Sensor fault alternatively cable fault on one of the refrigerant sensors. The heat
pump goes to failsafe mode and defrosts on time.
REFR.1 SENSOR Sensor fault alternatively cable fault. Refrigerant sensor 1
REFR.2 SENSOR Sensor fault alternatively cable fault. Refrigerant sensor 2
LOW RETURN TEMP 1 The return line temperature is too low to start a defrosting.
LOW RETURN TEMP 2 The return line has fallen too low during defrosting.
LOW EVAP. TEMP 1 Evaporation temperature too low.
LOW EVAP. TEMP 2 Too great a deviation in evaporation temperature average value.
SUCTION TEMP SENSOR Sensor fault alternatively cable fault.
ROOM SENSOR Sensor fault alternatively cable fault.
DISCHARGE PIPE SENSOR Sensor fault alternatively cable fault.
DISTR. CIR. 1 SENSOR Sensor fault alternatively cable fault.
DISTR. CIR. 2 SENSOR Sensor fault alternatively cable fault.
POOL SENSOR Sensor fault alternatively cable fault.
COM. ERROR HP-CARD Communication broken between display card and heat pump card (outdoor).
COM. ERROR HUB-CARD Communication broken between display card and hub card (indoor).
Service instructions VMGFJ102 – 9

Message Meaning
COM. ERROR EXV-CARD Communication broken between display card and expansion valve control
card (outdoor).
COM. ERROR EXPANSION CARD Communication broken between display card and expansion card (indoor).
Note! In event of alarm the heat pump will if possible supply heating to the house, primarily with the
compressor, secondarily with the auxiliary heater. Hot water will stop to indicate that something
noteworthy has occurred.
3.2 Components
3.2.1 Outdoor unit
11
10
12
13
14
16
15
17
1
2
3
4
5
6
7
8
9
19
18
Figure 1. Components
Position Name Position Name
1 Electrical cabinet 11 Electronic expansion valve
2 Fan 12 Receiver
10 – Service instructions VMGFJ102

Position Name Position Name
3 Pressure transmitter 13 Drying filter
4 Suction line 14 Heat exchanger
5 Compressor 15 Flow sensor
6 High pressure switch 16 Heating system supply line
7 Operating pressure switch 17 Return line heating system
8 Four-way valve 18 Solenoid
9 Discharge pipe 19 Non-return valve
10 Air heat exchanger
3.2.2 Indoor unit
1
DHP-AQ Mini
1
2
4
35
DHP-AQ Maxi
1
2
34
DHP-AQ Midi
Position Description
1 Control module (transparent in image)
2 Immersion heater
3 Reversing valve
4 Circulation pump
5 Water heater
3.3 Measurement points
Caution! When reading the resistance of the sensors, the sensor leads must first be disconnected from the
control equipment.
Service instructions VMGFJ102 – 11

Table 1. Outdoor / Defrost sensor
°C 150 ohm, Ω
-30 1884
-25 1443
-20 1115
-15 868
-10 681
-5 538
0 428
5 343
10 276
15 224
20 183
25 150
30 124
35 103
40 86
Table 2. PT1000 sensor
°C 1000 ohm, Ω
0 1000
10 1039
20 1078
30 1117
40 1155
50 1194
60 1232
70 1271
Table 3. Other sensors
°C 22 kilo ohm, kΩ
0 66,3
5 52,4
10 41,8
15 33,5
20 27,1
25 22,0
30 18,0
35 14,8
40 12,2
45 10,1
50 8,5
55 7,1
60 6,0
65 5,0
70 4,2
75 3,7
80 3,1
85 2,7
3.3.1 Measurement checking sensors during fault tracing
1. Disconnect the relevant sensor from I/O-card/terminal block.
2. Measure the resistance for the sensor and any extension cables.
3. Then measure the sensor only.
Note! To ensure the sensor value the actual temperature must be checked against the measured
resistance.
12 – Service instructions VMGFJ102

3.3.2 Positioning sensors
7
7
8
9
Heat pump DHP-AQ Midi DHP-AQ Maxi
Symbol explanation
1 DISCHARGE PIPE SENSOR
2 SUCTION TEMP SENSOR
3 REFR.1 SENSOR
4 REFR.2 SENSOR
5 DEFROST SENSOR (located to rear beside air intake)
6 OUTDOOR SENSOR (positioned on wall to north)
7 SUPPLY LINE SENSOR
8 HOT WATER TOP
9 HOT WATER SENSOR
RETURN LINE SENSOR - Located on return pipe that runs to heat pump. See system solution in the Installa-
tion instructions.
Service instructions VMGFJ102 – 13

3.4 Check points
Table 4. Temperatures
Name Values
Condensing temperature 0.5 – 1.5 °C above supply line temperature
Evaporation temperature 7 - 8 °C
Radiator circuit 8°K temperature difference
Overheating R407C 4K ±1 K
Table 5. Break pressure switch/pressure transmitter
Refrigerant Pressure switch/pressure transmitter Break pressure
R407C OP (operating pressure switch) 2.85 MPa
High pressure switch 3,10 MPa
Pressure transmitter low pressure 0.04 MPa
Following parameters can be read off in the display:
•Suction gas temperature
•Evaporation pressure
•Evaporation temperature (calculated from ”Dew point”)
•Opening percent EXV
•Superheating
This means new opportunities to diagnose the heat pump, without needing to remove the covers and work on the
cooling circuit.
•In normal operation the heat pump operates with superheating of 5.5°C – 7°C, the expansion valve's degree of
opening will vary depending on operating situation.
•At outdoor temperatures of -5°C or lower the opening degree is below 20%
•At outdoor temperatures of +5C to +13°C the opening degree is around 40-50%
•When cooling (A35W18) the degree of opening is 100%
If superheating is >9°C and the degree of opening of the expansion valve lies steady at 100% this can indicate that
a significant part of the refrigerant has leaked from the heat pump. If this is the case the heat pump must be
checked by service technicians with personal refrigeration certificates!
3.5 Operational problems
The tables list the most probable and common causes of the problem first. When troubleshooting the cause of a
problem start with the first cause and go down the list. There may be more than one way of troubleshooting a
cause where the most probable is given first.
14 – Service instructions VMGFJ102

3.5.1 Alarm
Table 6. Problem – Alarm LP (lower pressure transmitter)
Cause Troubleshooting Remedy
1. Cable break or loose cable to lower
pressure transmitter. •Check that both cables are connected
to the lower pressure transmitter.
•Using the buzzer, check that there are
no cable breaks. In order to do this,
disconnect the cables from the lower
pressure transmitter and circuit
board.
If a cable has come loose, reconnect it.
If there is a cable break, replace the
cable.
2. The pressure transmitter opens too
soon. •Pressure transmitter fault, opens at a
higher pressure than indicated. Check
break pressure using the manometer
apparatus.
If the pressure transmitter breaks too
early, replace it.
3. Lack of refrigerant, not enough
refrigerant in the system. Using manometer apparatus and ther- mometer, check that the unit’s overheat-
ing is correct for the specific refrigerant.
Follow the correct procedure (depend-
ing on type of refrigerant) to add the cor-
rect amount of refrigerant.
If there appears to be a leak in the refrig-
erant circuit, carry out leak tracing and
any necessary corrective action.
4. Drying filter blockage. Check the temperature difference above
the drying filter. A difference of max 1°C is
permissible. If the difference is greater, the
filter is blocked. Take a reading during
operation.
If the drying filter is sealed, replace it.
5. Blocked evaporator on the refriger-
ant side. Using manometer apparatus and ther- mometer, check that the unit’s overheat-
ing is correct for the specific refrigerant.
If the evaporator is thought to be
blocked by oil for example, try blowing
nitrogen through it to release the oil. If
this does not work, it must be replaced
Table 7. Problem – Alarm HP (high pressure switch)
Cause Troubleshooting Remedy
1. Air in the heating system. Listen for air in the heat pump and heat-
ing system. Bleed the heating system according to the installation instructions.
2. Blocked strainer in the heating sys-
tem. Check that the strainer is not blocked. Clean the strainer if necessary.
3. Closed or partially closed thermo-
stats/valves in the heating system. Check that the thermostats/valves in the heating system are open. Open closed thermostats/valves.
4. The circulation pump that is defec-
tive or has jammed. Is there voltage and 0 – 10V signal (applies to A classed circulation pumps) up to the
circulation pump?
Check that the circulation pump is active
in the control system’s manual test
menu.
Check if there is voltage to the circula-
tion pump, if there is, and it does not run,
the circulation pump is jammed. If this is
the case, open the bleed screw and try to
release the paddle wheel using a screw-
driver for example (Does not apply to
heat pumps in Opti).
If there is no voltage to the circulation
pump, check if there is voltage from the
I/O card, see wiring diagram. If there is
voltage from the I/O card, check the
components between the I/O card and
the circulation pump.
If a component is defective, replace it.
Service instructions VMGFJ102 – 15

Cause Troubleshooting Remedy
5. Shut-off main tap in heating sys-
tem. Check that the main tap is open. Open closed main tap.
6. Cable break or loose cable to high
pressure switch. •Check that both cables are connected
to the pressure switch.
•Using the buzzer, check that there are
no cable breaks. In order to do this,
disconnect the cables from the pres-
sure switch and circuit board.
If a cable has come loose, reconnect it.
If there is a cable break, replace the
cable.
7. The high pressure switch does not
open. •Incorrect pressure switch installed.
Same or higher break pressure than
the high pressure switch. See mark-
ing.
•Pressure switch fault, opens at a
higher pressure than indicated (mark
pressure). Check using the manome-
ter apparatus.
•Defective pressure switch, never
opens.
If the high pressure switch does not
open, replace it.
8. The high pressure switch opens too
soon. •Incorrect pressure switch installed. As
low or lower break pressure than
operating pressure switch. See mark-
ing.
•Pressure switch fault, opens at a lower
pressure than indicated (mark pres-
sure). Check using the manometer
apparatus.
•Defective pressure switch, always
open.
If the high pressure switch opens too
soon or is always open, replace it.
9. External system shunt that closes
on time setting. Check for shunts or valves in the system, which are timer-controlled, that close
down the entire or too large a part of the
heating system.
Always ensure that there is a sufficiently
large water volume for the heat pump to
work against, i.e. for the heat to give off
its heat to.
10. Incorrectly facing non-return valve
with too high opening pressure. •Check the system’s direction of flow
and that the non-return valve is
turned the correct way.
•Check that the heat pump’s external
available pressure exceeds the non-
return valve’s opening pressure.
If the non-return valve is facing the
wrong way, turn it.
If the non-return valve has too great an
opening pressure, replace it.
11. Large pressure drop in the heating
system. •Dirt in the heating system.
•Closed or partially closed thermo-
stats/valves in the heating system.
•Under dimensioned pipe system.
Check that the HP’s external available
pressure exceeds the system pressure
drop.
If necessary, clean/flush the heating sys-
tem.
Open closed thermostats/valves.
If there is not sufficient pressure equip-
ment, the heating system can be adjus-
ted according to the system solution for
large pressure drop.
16 – Service instructions VMGFJ102

Cause Troubleshooting Remedy
12. Blocked condenser on the water
side. If there is no strainer in the heating sys- tem, there is a risk of dirt sticking in the
condenser and blocking it. Unfortunately
there is no easy way of checking if the
condenser is blocked.
You can carry out a test by allowing the
compressor and circulation pumps to
remain in operation and after a while,
check that the pressure pipe becomes hot
and that the circulation pumps work (for
circ.pumps with a bleed screw, unscrew it
and feel if the pump rotor rotates using a
screwdriver).
Then read the temperature on both con-
nection pipes to the condenser:
If the temperature difference is <3°C, the
condenser is probably blocked.
If the temperature difference is 3-13°C, it is
probably not blocked.
If the temperature difference is >13°C, the
condenser is probably blocked.
If the condenser is thought to be
blocked, try flushing it. If this does not
work, it must be replaced
13. Blocked condenser on the refriger-
ant side. Using manometer apparatus and ther- mometer, check that the unit’s overheat-
ing is correct for the specific refrigerant.
If the condenser is thought to be blocked
by oil for example, try blowing nitrogen
through it to release the oil. If this does
not work, it must be replaced
14. Overfilled refrigerant circuit. Using manometer apparatus and ther-
mometer, check that the unit’s overheat-
ing is correct for the specific refrigerant.
Follow the correct procedure (depend-
ing on type of refrigerant) to add the cor-
rect amount of refrigerant.
If there appears to be a leak in the refrig-
erant circuit, carry out leak tracing and
any necessary corrective action.
Table 8. Problem – Alarm MS (motor protection)
Cause Troubleshooting Remedy
1. Phase drop or blown fuse. Check the fuses in the fuse box. Check that
all phases are present on the terminal
block for incoming supply. Also check that
all wiring is secure, if screw terminals are
used they must be properly tightened, if
phoenix flat spring terminals are used, the
cables must be secure in the correct hole
with load on the cable.
If any of the phases are missing, check
backwards towards the building’s main
electrical cabinet. If there are no phases
there, contact the network supplier.
2. Cable break. Check the supply to the motor protection,
soft-starter or compressor. If a cable is damaged, replace it.
3. Defective soft-starter (three-phase
heat pump). Measurement check and establish that when the Heat pump card gives a signal
(there must be voltage between A1 & A2
on the soft-starter), the soft-starter relea-
ses all three phases down to the compres-
sor.
If the soft-starter does not release the
phases when it receives signals from the
heat pump card, replace it.
4. Defective soft-starter (single phase
heat pump). Check measure and establish that when the Heat pump card gives a signal (there
must be voltage between ON and N on
the soft-starter), the soft-starter releases
the phases to the compressor.
If the soft-starter does not release the
phases when it receives signals from the
heat pump card and does not alarm as
below, replace it.
Service instructions VMGFJ102 – 17

Cause Troubleshooting Remedy
5. Defective or incorrectly set motor
protection. Use a hook-on meter to establish when the motor protection deploys, check what
the motor protection is set to.
Compare with the table. For three phase
heat pumps all three phases must be sup-
plied.
If the motor protection is defective,
replace it.
If incorrectly set, adjust to the correct
value.
6. Defective compressor. Measurement check the voltage on the
phase(s) (each to zero) at the compressor.
There must not be any large deviation
between the phases. If measurement
checking the winding’s resistance the
same value must be on one to three wind-
ings.
If the compressor is defective, replace it.
7. Alarm from single phase soft starter. Check the fault cause using the soft start
LEDs.
Table 9. Problem – Alarm sensor (all)
Cause Troubleshooting Remedy
Sensor fault alternatively cable fault. •When reading the resistance of the
sensors, the sensor leads must first
be disconnected from the control
equipment or terminal block.
•First take a reading from the sensor
including cable and check against
the ohm table in Symbols on decals.
•If the read off value does not corre-
spond with the table, only measure
the sensor and check the ohm table
in Measurement points, Page 11.
If the sensor gives a correct value, the
cable is defective.
If the sensor does not give a correct
value, the sensor is defective.
Table 10. Problem – Err phase seq.
Cause Troubleshooting Remedy
The incoming phases have the incor-
rect sequence (only applies to 3-phase
heat pumps), appears after a minute
when the compressor is started.
•If the text HEAT / PRESSURE ERROR is
displayed it can mean that the pha-
ses are in the incorrect order.
•When the compressor is running,
check the pressure pipe temperature
by feeling the pressure pipe. If the
phases are correctly sequenced it
should be hot (not just warm) even a
distance from the compressor.
•When the compressor runs with the
phases incorrectly sequenced a
strange noise may be heard (loud,
rattling) when the compressor runs
backwards.
If the phases are in the incorrect order,
switch two incoming phases at the main
terminal block and recheck according to
the troubleshooting window.
18 – Service instructions VMGFJ102