Danfoss DHP-A Operating instructions

MAKING MODERN LIVING POSSIBLE
Service instructions
Domestic heat pumps
DHP-A
DHP-A Opti
DHP-C Opti
DHP-C
DHP-H
DHP-H Opti
DHP-H Opti Pro
DHP-L
DHP-L Opti
DHP-L Opti Pro
DHP-C Opti W/W
www.heating.danfoss.com

Danfoss A/S is not liable or bound by warranty if these
instructions are not adhered to during installation or service.
The English language is used for the original instructions.
Other languages are a translation of the original instructions.
(Directive 2006/42/EC)
© Copyright Danfoss A/S

Table of Contents
1 Installing accessories/additional functions ............................................... 4
1.1 Room sensor ................................................................ 4
1.2 EVU function ................................................................ 5
1.3 Tariff control ................................................................ 5
1.4 Level switch ................................................................. 6
2Troubleshooting ................................................................. 7
2.1 Alarm ..................................................................... 7
2.2 Measurement points ........................................................... 7
2.3 Check points ................................................................ 8
2.4 Operational problems .......................................................... 9
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 3

1 Installing accessories/additional functions
Danger Hazardous electrical voltage! The terminal blocks are live and can be highly dangerous due to the risk of elec-
tric shock. All power supplies must be isolated before electrical installation is started.
1.1 Room sensor
The room temperature sensor has a temperature sensor that provides a further value that the control system can use when calculating
the supply temperature. The impact of the room sensor in the calculation can be set in the menu HEAT CURVE -> ROOM FACTOR. Default
setting for ROOM FACTOR is 2 but can be adjusted from 0 (no impact) to 4 (large impact).
The difference between the desired and actual indoor temperature is multiplied by the set value for ROOM FACTOR. The set point on the
heating system’s supply line increases or decreases with the result depending on whether there is a deficit or surplus of heat.
The table below shows examples of how the set point for the supply line is affected at CURVE 40 with different settings for ROOM FAC-
TOR.
In the event of a heating deficit:
ROOM FACTOR Desired room temperature, °C Actual room temperature, °C Set point for supply line, °C
0 20 18 40
1 20 18 42
2 20 18 44
3 20 18 46
4 20 18 48
In the event of a surplus of heat the conditions are the opposite:
ROOM FACTOR Desired room temperature, °C Actual room temperature, °C Set point for supply line, °C
0 20 22 40
1 20 22 38
2 20 22 36
3 20 22 34
4 20 22 32
Install the room sensor
N
The room sensor is connected to a safety extra-low voltage.
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
4

1. Install the room temperature sensor in a location in the house where the room temperature is relatively constant:
▪Centrally located in the house
▪At eye level
▪Not in direct sunlight
▪Not in a draft
▪Not in a room with alternative heating
2. Break all power supply to the heat pump.
3. Remove the front cover from the heat pump.
4. Route the room sensor’s connecting cable through the opening in the top panel up to the connecting block.
5. Connect the cable as follows.
303
304
6. Install the front cover on the heat pump. Switch on the power supply.
7. Hang a thermometer next to the room sensor.
8. Calibrate the sensor by holding in both buttons for 15 seconds until the display starts to flash.
9. Set the actual room temperature that the thermometer shows.
10. Wait 10 seconds until the display stops flashing.
If the display shows "--" for indoor temperature no indoor temperature has been read.
1.2 EVU function
When connecting between terminal blocks 307 and 308 the EVU (Elektrizitäts Versorgungs Unternehmen) function is achieved. This pre-
vents operation of the heat pump, auxiliary heater and circulation pump for the brine circuit. The exception is the circulation pump
heating circuit which is permitted to run. The text EVU STOP is shown in the display when this function is active.
1. Break all power supply to the heat pump.
2. Remove the front cover from the heat pump.
3. Route the EVU function’s connecting cable through the opening in the top panel up to the connecting block.
4. Connect the cable as illustrated below.
307
308
5. Install the front cover on the heat pump. Switch on the power supply.
1.3 Tariff control
When connecting between terminal blocks number 307 and 308 over a 10 kΩ resistor the tariff control function is active which gives the
opportunity of a recurring temporary reduction of the indoor temperature.
The extent of the tariff control is set in the menu INFORMATION -> HEAT CURVE -> REDUCTION.
1. Break all power supply to the heat pump.
2. Remove the front cover from the heat pump.
3. Route the tariff control function’s connecting cable through the opening in the top panel forward to the connecting block.
4. Connect the cable as illustrated below.
307
308
10 kΩ
5. Install the front cover on the heat pump. Switch on the power supply.
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 5

1.4 Level switch
In certain countries there is a requirement that the heat pump must be equipped with a level switch for the brine system. Always check
local rules and regulations before commissioning the heat pump.
2
1
3
1 Safety valve
2 Level switch
3 Floats
Connect the flow sensor according to the installation instructions supplied with the accessory.
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
6

2 Troubleshooting
2.1 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.
HIGH PRES-
SURE ERROR Tripped high pressure switch. Compressor stop- ped. RETURN LINE SENSOR Return sensor fault. Return temperature = Supply line -5 is used. Calculated supply temperature
limited to maximum 45°C.
LOW PRES-
SURE ERROR Tripped low pressure switch. Compressor stop- ped. HOT WATER SENSOR Fault on sensor for start temperature. No hot wa- ter production.
MOTOR P ER-
ROR Deployed overload relay (overcurrent relay) com- pressor, deployed overload relay for outdoor unit
fan. On certain models alarms from the brine
pump or soft starter can also occur. Compressor
stopped.
DEFR SEN-
SOR Defrost sensor fault. Heating and hot water pro- duction is controlled from the outdoor sensor’s
value instead (applies to the DHP-A models).
BRINE OUT Brine out is less than the set minimum tempera-
ture. Compressor stopped. No hot water produc-
tion.
COOLING
TEMP Sensor fault. Cooling function stops.
LOW BRINE-
FLOW Flow sensor not active during last start. Compres- sor stopped. No hot water production. ERR PHASE SEQ. Alarm that indicates that there is an incorrect phase sequence to the compressor. Only display
and only the first 10 minutes.
AUX. HEATER
ERROR Overheating protection deployed. No auxiliary heater. HIGH RE- TURN Alarm that indicates that high return temperature prevents the compressor’s operation.
OUTDOOR
SENSOR Fault in outside sensor. When the control system calculates the heat demand, zero degrees is used. RVV PASSIVE COOLING Error detected on exchange valve at start up. Ap- plies to DHP-C models.
SUPPLY LINE
SENSOR Supply line sensor error. Everything stops except the heating system’s circulation pump. FLOW SEN- SOR Error detected on flow switch. Applies to DHP-C models.
In event of alarm the heat pump will, if possible, supply heating to the house. Primarily with the compressor, secondarily with the auxili-
ary heater. Hot water will stop to indicate that something noteworthy has occurred.
2.2 Measurement points
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.
Caution When reading the resistance of the sensors, the sensor leads must first be disconnected from the control
equipment.
N
To ensure the sensor value the actual temperature must be checked against the measured resistance.
Measurement checking sensors during fault tracing
°C ohm, Ω outdoor and defrost sensors 1000 ohm, Ω kilo ohm, kΩ other sensors
-30 1884
-25 1443
-20 1115
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 7

°C ohm, Ω outdoor and defrost sensors 1000 ohm, Ω kilo ohm, kΩ other sensors
-15 868
-10 681
-5 538
0 428 1000 66,3
5 343 52,4
10 276 1039 41,8
15 224 33,5
20 183 1078 27,1
25 150 22,0
30 124 1117 18,0
35 103 14,8
40 86 1155 12,2
45 10,1
50 1194 8,5
55 7,1
60 1232 6,0
65 5,0
70 1271 4,2
75 3,7
80 3,1
85 2,7
2.3 Check points
Temperatures Values
Condensing temperature 0,5 – 1,5°C above supply line temperature
Evaporation temperature 7 - 8°C lower than incoming brine
Superheating 4 - 8 K temperature difference
Radiator circuit 5 - 10 K temperature difference
Brine circuit 2 - 5 K temperature difference
Overheating R407C 4K ±1 K
Expansion valve factory setting Setting
Danfoss TUBE R404A, 4.2 kW From fully closed position, screw 3 turns out
Danfoss TUBE R404A, 5.6 kW From fully closed position, screw 5,5 turns out
Danfoss TUBE R404A, 8,4 kW From fully closed position, screw 5 turns out
Danfoss TUBE R404A, 12.0 kW From fully closed position, screw 5.25 turns out
Danfoss TUBE R404A, 15.3 kW From fully closed position, screw 2.75 turns out
Danfoss TUBE R407C, 11.0 kW From fully closed position, screw 6.25 turns out
Danfoss TUBE R407C, 17,0 kW From fully closed position, screw 5,5 turns out
Refrigerant Pressure switch Break pressure
R404A (Only applies to the DHP-A models) Low pressure switch 0.08 MPa
Operating pressure switch A 2.65 MPa
Operating pressure switch B 2.85 MPa
High pressure switch 3,10 MPa
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
8

Refrigerant Pressure switch Break pressure
R407C Low pressure switch 0.08 MPa
Operating pressure switch 2.85 MPa
High pressure switch 3,10 MPa
2.4 Operational problems
The tables in the following section apply to all types of heat pump and collector solutions.
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.
2.4.1 Alarm
Problem – Alarm LP (low pressure switch)
Cause Troubleshooting Remedy
1. Blocked strainer on the brine cir-
cuit. Check that the strainer is not blocked. Clean the strainer if necessary.
2. Air in the brine circuit. Listen for air in the heat pump and brine circuit. Bleed the brine circuit according to the in-
stallation instructions.
3. Closed taps, main tap or filler
cock on the brine circuit. Check that the stopcock or any other taps are open. Open closed taps.
4. The circulation pump for the
brine circuit is defective or has jam-
med.
Check:
▪That the circulation pump spins.
▪That the shut-off valves are open.
▪That the strainer is not blocked.
▪That there is no air in the heating system.
The circulation pump may have jammed. If
so, open the bleed screw and try to release
the paddle wheel using a screwdriver for
example.
Open closed valves or taps.
Check, and, if necessary, clean the strainer.
If necessary, bleed the heating system ac-
cording to the installation instructions
5. Cable break or loose cable to low
pressure switch. ▪Check that both cables are connected to the
pressure switch.
▪Using the buzzer, check that there are no ca-
ble breaks. In order to do this, disconnect the
cables from the pressure switch and circuit
board.
If a cable has come loose, reconnect it.
If there is a cable break, replace the cable.
6. The low pressure switch opens
too soon. ▪Incorrect pressure switch installed. Higher
break pressure than intended. See marking.
▪Pressure switch fault, opens at a higher pres-
sure than indicated (mark pressure). Check us-
ing the manometer apparatus.
▪Defective pressure switch, always open.
If the low pressure switch opens too soon
or is always open, replace it.
7. Incorrect type of anti-freeze, must
be in accordance with instructions. Check that the correct type of anti-freeze is used. If the incorrect type of anti-freeze is used, the entire system must be drained and refil-
led with a new mixture.
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 9

Cause Troubleshooting Remedy
8. Incorrect mix of anti-freeze, the
concentration must be in accord-
ance with instructions.
Check the freezing point of the mix using a refrac-
tometer. If the mixture is not in accordance with the instructions, it must be remixed in an exter-
nal container. This is because the fluids do
not mix with each other well if one is filled
directly into the system.
9. Short active collector, e.g. short
or dry bore hole, short surface soil
collector.
▪Check the length of the collector that is being
used and compare with the collector length in
the dimensioning documentation.
▪In addition, check that the collector is not sus-
pended "in free air" if boreholes are used.
If the active collector is too short, the heat
pump cannot receive enough energy from
the heat source , which results in it requir-
ing an addition to cover the energy require-
ment.
10. Collector too long, pressure
drop too great. Check the length of the collector that is being used and that it is connected in parallel (not connected
in series) if more than 1 coil is being used.
If a longer collector is being used than rec-
ommended for the specific heat pump, it
must be divided on several parallel connec-
ted coils.
11. Expansion valve defective or in-
correctly set. ▪Using manometer apparatus and thermome-
ter check what the overheating reading of the
unit is.
▪Also check that bulb and capillary tube are un-
damaged and that the bulb is correctly instal-
led.
If the overheating reading does not corre-
spond with the instructions for the specific
refrigerant, adjust the expansion valve until
the correct value is obtained. See separate
instructions for cooling techniques.
If overheating cannot be adjusted with the
expansion valve or if the capillary tube/
bulb is damaged, replace it.
12. Lack of refrigerant, not enough
refrigerant in the system. Using manometer apparatus and thermometer, check that the unit’s overheating is correct for the
specific refrigerant.
Follow the correct procedure (depending
on type of refrigerant) to add the correct
amount of refrigerant.
If there appears to be a leak in the refriger-
ant circuit, carry out leak tracing and any
necessary corrective action.
13. Drying filter blockage. Check the temperature difference above the drying
filter. A one degree difference is permissible. If the
difference is greater, the filter is blocked. Take a
reading during operation.
If the drying filter is sealed, replace it.
14. Blocked evaporator on the wa-
ter side. If there is no strainer in the brine circuit, there is a risk of dirt sticking in the evaporator and blocking
it. Unfortunately there is no easy way of checking if
the evaporator is blocked.
You can carry out a test by allowing the compres-
sor and circulation pumps to remain in operation.
Check 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 connection
pipes to the evaporator:
If the temperature difference is <1°C, the evapora-
tor is probably blocked.
If the temperature difference is 2-6°C, it is probably
not blocked.
If the temperature difference is >6°C, the evapora-
tor is probably blocked.
If the evaporator is thought to be blocked,
try flushing it. If this does not work, it must
be replaced
15. Blocked evaporator on the re-
frigerant side. Using manometer apparatus and thermometer, check that the unit’s overheating 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
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
10

Problem – Alarm HP (high pressure switch)
Cause Troubleshooting Remedy
1. Blocked strainer in the heating
system. Check that the strainer is not blocked. Clean the strainer if necessary.
2. Air in the heating system. Listen for air in the heat pump and heating system. Bleed the heating system according to the
installation instructions.
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 de-
fective or has jammed. Is there voltage 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 circulation
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 re-
lease the paddle wheel using a screwdriver
for example (Does not apply to speed con-
trolled heat pumps).
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.
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 ca-
ble breaks. In order to do this, disconnect the
cables from the pressure 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 marking.
▪Pressure switch fault, opens at a higher pres-
sure than indicated (mark pressure). Check us-
ing the manometer 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 marking.
▪Pressure switch fault, opens at a lower pres-
sure than indicated (mark pressure). Check us-
ing 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.
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 11

Cause Troubleshooting Remedy
10. Incorrectly facing non-return
valve with too high opening pres-
sure.
▪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 open-
ing 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 heat-
ing system. ▪Dirt in the heating system.
▪Closed or partially closed thermostats/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 system.
Open closed thermostats/valves.
If there is not sufficient pressure equip-
ment, the heating system can be adjusted
according to the system solution for large
pressure drop.
12. Overfilled refrigerant circuit. Using manometer apparatus and thermometer,
check that the unit’s overheating is correct for the
specific refrigerant.
Follow the correct procedure (depending
on type of refrigerant) to add the correct
amount of refrigerant.
If there appears to be a leak in the refriger-
ant circuit, carry out leak tracing and any
necessary corrective action.
13. Blocked condenser on the water
side. If there is no strainer in the heating system, 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 compres-
sor and circulation pumps to remain in operation
and after a while, check that the pressure pipe be-
comes hot and that the circulation pumps work
(for circulation pumps with a bleed screw, unscrew
it and feel if the pump rotor rotates using a screw-
driver).
Then read the temperature on both connection
pipes to the condenser:
If the temperature difference is <3°C, the condens-
er is probably blocked.
If the temperature difference is 3-13°C, it is proba-
bly not blocked.
If the temperature difference is >13°C, the con-
denser is probably blocked.
If the condenser is thought to be blocked,
try flushing it. If this does not work, it must
be replaced
14. Blocked condenser on the refrig-
erant side. Using manometer apparatus and thermometer, check that the unit’s overheating 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
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
12

Problem – Alarm MS (motor protection)
Cause Troubleshooting Remedy
1. Phase drop or blown fuse. Check that all phases are present on the terminal
block for incoming supply. If not, check the fuses in
the cabinet.
Also check that all wiring is secure, if screw termi-
nals 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. Defective soft-starter (three-
phase heat pump). Measurement check and establish that when the I/O card gives a signal (there must be voltage be-
tween A1 & A2 on the soft-starter), the soft-starter
releases all three phases down to the compressor.
If the soft-starter does not release the pha-
ses when it receives signals from the I/O
card, replace it.
3. Defective soft-starter (single
phase heat pump). Check measure and establish that when the I/O card gives a signal (there must be voltage between
ON and N on the soft-starter), the soft-starter relea-
ses the phases to the compressor.
If the soft-starter does not release the pha-
ses when it receives signals from the I/O
card and does not alarm as below, replace
it.
4. Defective or incorrectly set motor
protection. Use a hook-on metre to establish when the motor protection deploys, check what the motor protec-
tion 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.
5. Cable break. Check the supply to the motor protection, soft-
starter or compressor. If a cable is damaged, replace it.
6. Defective compressor (applies to
3-phase heat pumps). Measurement check the voltage on the three pha- ses (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 all three windings.
If the compressor is defective, replace it.
7. Alarm from the overload protec-
tion on the brine pump (only cer-
tain heat pump models).
Switch the heat pump off and on. If the alarm re-
mains check the WSK switch in the brine pump. If the brine pump is defective, replace it.
8. Alarm from single phase soft
starter. Check the fault cause using the soft start LEDs.
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, see
chapter Measurement points.
▪If the read off value does not correspond with
the table, only measure the sensor and check
the ohm table, see chapter Measurement
points.
If the sensor gives a correct value, the cable
is defective.
If the sensor does not give a correct value,
the sensor is defective.
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 13

Problem – Incorrect phase sequence
Cause Troubleshooting Remedy
The incoming phases have the in-
correct sequence (only applies to 3-
phase heat pumps).
▪If the text ERR PHASE SEQ. appears in the dis-
play when the heat pump is powered, (only
appears in the first 10 minutes) this means
that the phases have the incorrect sequence.
▪When the compressor is running, check the
pressure pipe temperature by feeling the
pressure pipe. If the phases are correctly se-
quenced it should be hot (not just warm) even
a distance from the compressor.
▪When the compressor runs with the phases in-
correctly 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.
Problem – Alarm AH (auxiliary heat)
Cause Troubleshooting Remedy
1. The overheating protection has
tripped. Check if the overheating protection has tripped. If the overheating protection has tripped, reset it.
2. Phase drop.
The alarm occurs when 230 V is not
registered between L2 on the circuit
board and N.
▪Check if the overheating protection has trip-
ped.
▪Check if any cables at the circuit board or
overheating protection are loose or damaged.
If the overheating protection has tripped,
reset it.
If the cables are loose or damaged, secure
or replace them.
3. Overheating protection fault,
cannot be reset. Press the reset button, measurement check for 230 V on the incoming and outgoing connections. If the overheating protection is defective, replace it.
4. Flow sensor fault. Check what the flow sensor shows. Is it a plausible/
actual value?
Measure the resistance of the sensor, check against
the ohm table, see chapter Measurement points.
If the sensor is defective, replace it.
5. No or insufficient circulation in
the heating system. Check:
▪That the circulation pump spins
▪That the shut-off valves are open.
▪That the strainer is not blocked.
▪That there is no air in the heating system.
The circulation pump may have jammed. If
so, open the bleed screw and try to release
the paddle wheel using a screwdriver for
example.
Open closed valves or taps.
Check, and, if necessary, clean the strainer.
If necessary, bleed the heating system ac-
cording to the installation instructions.
6. The submersible tube in the elec-
tric heating element is against the
coils.
Check what the flow temperature is when the over-
heating protection trips. This normally trips at 95°C. The submersible tube can be prised out slightly from the coils using a screwdriver
or similar. The submersible tube must be
vertical.
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
14

Problem – Alarm Brine out
Cause Troubleshooting Remedy
1. Defective sensor. Check what the sensor shows. Is it a plausible/
actual value?
Measure the resistance of the sensor, check against
the ohm table, see chapter Measurement points.
If the sensor is defective, replace it.
2. Brine temperature too low. Check the set value on ALARM BRINE in the heat
pump’s control computer. The alarm is triggered when the tempera- ture on BRINE OUT is as low or lower than
the set value on ALARM BRINE. In the facto-
ry setting this function is inactive.
Problem – Alarm Brine flow low
Cause Troubleshooting Remedy
1. Incorrect system selected in the
control system.
If the system does not contain a
flow sensor but the control system
is set for the system with flow sen-
sor, this alarm occurs.
In the menu SYSTEM, check which system is selec-
ted. If the incorrect system is selected, change it.
2. Insufficient flow. ▪Check whether the ground water pump is run-
ning.
▪Check the flow sensor.
▪Calibration/setting the flow sensor.
▪Blocked exchanger?
The ground water pump must start and run
together with the heat pump’s integrated
brine pump.
Check against the wiring diagram that the
flow switch is correctly connected.
Check that the flow switch is set for the cor-
rect working range according to the flow
switch instructions.
If the exchanger is blocked, clean or replace
it.
Problem – Alarm brine pump
Cause Troubleshooting Remedy
The brine pump’s integrated alarm
has deployed. (Only applies to
speed-controlled heat pumps.)
▪Air in the brine pump?
▪Has the brine pump jammed?
Bleed the brine circuit according to the in-
stallation instructions.
If the brine pump has jammed, there is an
integrated shake function that attempts to
shake itself loose up to a maximum of 5
times, if it does not manage this, an alarm
will occur.
Try cutting the voltage to the heat pump to
stop the alarm and then manually run the
brine pump. If the alarm recurs, repeat the
procedure several times. If this does not
help, replace the brine pump.
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 15

Problem – Alarm circulation pump
Cause Troubleshooting Remedy
The circulation pump’s integrated
alarm has deployed. (Only applies
to speed controlled heat pumps)
▪Air in the circulation pump?
▪Has the circulation pump jammed?
Air in the brine circuit. See the installation
instructions for information on how to per-
form filling.
If the circulation pump has jammed, there
is an integrated shake function that at-
tempts to shake itself loose up to a maxi-
mum of 5 times, if it does not succeed, an
alarm will occur.
Try cutting the voltage to the heat pump to
stop the alarm and then manually run the
circulation pump. If the alarm recurs, repeat
the procedure several times. If this does not
help, replace the circulation pump.
Problem – Operating pressure switch open alternatively high hot gas temperature
Cause Troubleshooting Remedy
1. Operating pressure switch, func-
tion. 1. Switch off the main switch for the heat pump,
wait until the compressor has been stationary
for at least 15 minutes.
2. Disconnect the two cables on the pressure
switch, using a buzzer check if the pressure
switch is closed.
If the pressure switch is closed, bridge the
pressure switch cables temporarily and
switch on the voltage to the heat pump
again. If there is an indication 0 (zero) in the
display this means that the pressure switch
is fault-free and the problem is in the wiring
or in the circuit board.
If the pressure switch is open, try carefully
tapping the head of the pressure switch
with a screwdriver and use a buzzer test to
see if it has closed again.
Replace the pressure switch if it appears to
jam repeatedly.
2. Sensor fault. Check what the sensor shows. Is it a plausible/
actual value?
Measure the resistance of the sensor, check against
the ohm table in Measurement points.
If the sensor is defective, replace it.
3. Hot gas temperature too high. Check the set value on DISCH. PIPE in the heat
pump’s control computer (factory setting 140°C) The square symbol appears when the deliv- ery pipe temperature is as high or greater
than the set value for DELIVERY PIPE.
4. Overheating too high. Using manometer apparatus and thermometer
check what the overheating reading of the unit is.
Also check that bulb and capillary tube are undam-
aged and that the bulb is correctly installed.
If the overheating reading does not corre-
spond with the instructions for the specific
refrigerant, adjust the expansion valve until
the correct value is obtained. See separate
instructions for cooling techniques.
If overheating cannot be adjusted with the
expansion valve or if the capillary tube/
bulb is damaged, replace it.
5. Lack of refrigerant, not enough
refrigerant in the system. Using manometer apparatus and thermometer, check that the unit’s overheating is correct for the
specific refrigerant.
Follow the correct procedure (depending
on type of refrigerant) to add the correct
amount of refrigerant.
If there appears to be a leak in the refriger-
ant circuit, carry out leak tracing and any
necessary corrective action. If leak tracer is
not available, brush soap water on the sus-
pected leak and look for bubbles. Also
check for oil as this can come out from the
refrigerant circuit.
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
16

2.4.2 Leakage
Problem – Leak fluid side
Cause Troubleshooting Remedy
1. Insufficiently tightened connec-
tions. Locate the leak. ▪Tighten the connection and check that
it is sealed.
▪If it is still not sealed, replace the entire
connection and support sleeve (only
at soft pipes).
2. Cracked nut or connection. Locate the leak. Replace nut or connection.
3. Defective gasket or O-ring. Locate the leak. Replace the gasket or O-ring.
4. There is no overflow pipe connec-
ted to the safety valve(s). Establish which safety valve does not have an over- flow pipe. Install an overflow pipe according to the applicable norms.
5. Filler valve between incoming
cold water and heating system not
closed or leaking.
Check whether water continuously leaks from the
safety valve on the expansion vessel on the hot
side.
Try closing the filler valve and see if water
stops dripping from the safety valve. If not,
replace the filler valve.
6. No condensation drain to heat
pump’s drip tray. Check that condensation drain is installed and cor- rectly connected. Install the condensation drain that runs out into the floor drain.
7. Lack of condensation insulation
on cold water pipe and/or brine
pipe.
Establish where the condensation is coming from. The brine pipe must always be insulated. In
the event of problems with condensation
on the cold water pipes, insulate them.
Condensation often accumulates in joints
and angled sections of the insulation. Im-
prove the insulation.
8. Leak at soldered joints. Locate the leak. Drain the system of fluid, repair the leak. If
the leak is on the connection pipe to the
heat exchanger, also drain the refrigerant
side.
9. Leak at the condenser’s drain
cock. 1. Check that the valve is completely closed.
2. Check that the sealed cover is sealed.
If the sealed cover is not sealed, replace the
sealed cover or the entire drain tap.
10. Leak at the condenser’s bleed
valve. Check that it is completely closed. If it is fully closed and still leaks, replace it.
11. Leak at soldered joint on water
heater. Locate the leak. If there is a leak at the soldered joint, re- place the water heater.
12. Associated leak on the water
heater. ▪Establish whether water continuously leaks
from the safety valve on the expansion vessel
on the hot side.
▪Establish whether water continuously leaks
from the safety valve on the cold side.
If the water heater has a leak, replace it.
13. Associated leakage in the con-
denser. ▪Check for lack of refrigerant in the unit.
▪Check by smelling at the safety valve on the
hot side, open the valve and check.
If the condenser has a leak, replace it.
14. Anti-freeze is forced out of the
safety valve on the expansion tank
(brine system).
During the winter, water surrounding the hoses in
the borehole can freeze. In some cases, the ice can
push against the hoses slightly. Due to the reduc-
tion in volume in the hose, the anti-freeze fills the
expansion tank and eventually forces some fluid
out of the safety valve.
When the ice in the borehole melts and the hose
expands and returns to its original state, a vacuum
is generated which results in a reduction in tank
level. As the safety valve does not let any air in, the
expansion tank can retract inwards due to the vac-
uum created.
To prevent anti-freeze from being forced
out from the safety valve, you can ex-
change the existing expansion tank for a
closed pressure expansion vessel with a
greater volume.
To prevent the expansion tank retracting
inwards, a vacuum valve can be installed in
the system.
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 17

2.4.3 Noise
Problem – Noise problem in the radiator system
Cause Troubleshooting Remedy
1. Flexible hoses missing. Flexible hoses must be installed according to the
instructions. Install flexible hoses according to the in- structions.
2. Incorrectly installed flexible ho-
ses. Flexible hoses must be installed according to the instructions. Install flexible hoses according to the in- structions.
3. Installing/suspending pipes. Check if the mountings are too rigid, right type,
right sizes and/or installed too close together. If something seems to be incorrect accord- ing to the troubleshooting window, carry
out corrective actions.
4. Clicking. ▪Establish when clicking occurs, during heating
and/or in connection with completed hot wa-
ter production?
▪Locate the clicking noises.
A surge tank can be installed on the supply
line to mix the hot water with the existing,
slightly cooler, water, before it goes out to
the radiators.
Try lubricating lead-ins in walls, ceilings
and floors with silicone spray.
5. Circulation noise (whistling noise
in the heating system). Check the heating system.
▪Closed valves, choke valves, adjuster valves or
other restrictions in the radiator system can
cause circulation noise.
▪Is the heating system correctly adjusted for
flow?
▪Too great a flow in the heating system can
cause circulation noise.
If the incorrect type of valve is used to
choke the flow, replace with the correct
type.
If the heating system is not correctly adjus-
ted, make adjustments.
Can the heating system be run at a lower
flow?
Problem – Loud compressor noise
Cause Troubleshooting Remedy
1. Phase drop.
The compressor attempts to start or
operates on two phases (only ap-
plies to 3 phase heat pumps) .
1. Check that there is 400 V between incoming
phases on the heat pump.
2. If there is supply to the heat pump, measure
the voltage for all electrical components all
the way to the compressor, see wiring dia-
gram.
Check where the phase drop is and rectify.
2. Touching pipes – vibrations. Establish which pipe(s) is/are causing the problem. Try to release any tensions that cause the
vibrations.
3. Compressor fault. Determine whether the compressor is unusually
loud. If the compressor is defective, replace it.
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
18

Problem – Shrieking, whistling noise
Cause Troubleshooting Remedy
1. Whistling expansion valve. 1. Take overheating readings, adjust to the rec-
ommended value.
2. Open and close the valve fully in and out.
3. Adjust the expansion valve to recommended
overheating value again.
Check if the noise has stopped. If not, con-
tinue with point 2.
Continue with point 3.
If the problem persists, replace the expan-
sion valve.
2. Noise from the soft-starter. Measurement check the input and output phases
for the soft-starter as well as the control signals
from the I/O card (see wiring diagram).
If the soft-starter is defective, replace it.
3. The compressor’s IPR valve
opens. The compressor has an integrated IPR valve that opens at 28 ±3 bar.
When the valve opens, pressure equalizes between
the compressor’s high and low pressure sides and a
milling/whistling sound is heard.
To establish whether the valve opens at the correct
pressure, connect a manometer on the high and
low pressure sides.
When the valve opens, this is indicated by the pres-
sure on the low pressure side rising and reaching
the pressure on the high pressure side.
Check at what pressure the valve starts to open.
If it opens at too low a pressure, replace the
compressor.
Problem – Noise – miscellaneous
Cause Troubleshooting Remedy
1. Vibrating protective sleeves on
the pressure switches. Establish where the vibration noise is coming from. Prevent the protection sleeve vibrating by using insulation tape for example.
2. Vibration noise from the electrical
installation. Check for electrical steps or similar devices screwed to the heat pump and wall. These can cause vibra-
tions and noise.
Carry out according to the installation in-
structions.
3. The heat pump is not level. Check that the heat pump is level by using a spirit
level.
Check that the heat pump is supported by all four
feet.
If the heat pump is not level, adjust using
the feet.
4. General noise problems Carry out preventative measures. See Installation
instructions.Example:
▪Improve the acoustic environment in
the area where the heat pump in loca-
ted by installing acoustic panels on
the walls and ceiling.
▪Install a hood on the compressor
(most effective for high frequencies).
Service instructions Domestic heat pumps
Danfoss Heating Solutions VIGFI102 19

2.4.4 Hot-water
Problem – Temperature and/or quantity
Cause Troubleshooting Remedy
1. Defective 3-way valve motor. Check the function of the 3-way valve, that it runs
between the end positions by running a manual
test.
If the motor is defective, replace it.
2. Jammed 3-way valve insert.
The valve is not secure and releases
hot water to the radiators during
hot water production.
Detach the motor and test closing and opening of
the valve by pressing the control arm If the insert jams, remove and clean it, or re- place it.
3. Air in TWS coil or water outer
jacket. During hot water production:
▪Listen for air.
▪Check the temperature difference between
supply and return line.
Bleed the system.
A Large temperature difference can indi-
cate air in the system.
4. Start temperature set too high for
hot water production. Check that the start temperature is correctly set. Should not be set above the factory set value. ▪If the start value is set too high, reduce
it to the factory set value.
▪If the system has a high (>+8°C) brine
temperature, you may have to reduce
the start value further for a longer run-
ning time.
5. Sensor fault, hot water sensor.
Hot water production is started by
the hot water sensor.
Check what the hot water sensor (the start sensor)
shows. Is it a plausible/actual value?
Measure the resistance of the sensor, check against
the ohm table, see chapter Measurement points.
If the sensor is defective, replace it.
6. Large drain flow (>12l/min). Check how many litres of hot water (approximately
40°C) per minute drains from the tap. Use a clock
and bucket to measure the drain flow.
If the drain water flow is greater than 12l/
min, stratification in the water heater is af-
fected, which reduces the hot water capaci-
ty.
Suggested corrective actions:
▪Install a pressure reduction valve on
the incoming cold water pipe.
▪Change to a mixer with lower flow.
▪Adjust the drain flow on the existing
mixer, do not open the tap fully.
7. Water heater too small in relation
to requirement. How large is the requirement and what is the ca- pacity of the heater? Replace with a larger heater or supplement with an extra heater.
E.g. supplement with an DWH or an electric
heater.
8. The operating pressure switch
opens too soon (at too low a pres-
sure).
Hot water production ends when
the operating pressure switch
opens.
Check the break pressure using manometer appa-
ratus. If the pressure switch opens at the incorrect pressure, replace it.
The replacement pressure switch can be in-
stalled on the service output (Schrader
valve).
Service instructions Domestic heat pumps
VIGFI102 Danfoss Heating Solutions
20