Is the flow correct? Action
Yes Skip the next step of this procedure.
No Perform the next step of this procedure.
3 Connect a manifold to one of the service ports of the refrigerant circuit and check the pressure (suction, discharge). Compare with normal operation conditions of the unit.
Refrigerant pressure correct? Action
Yes Replace the body of the 4‑way valve,
see "3.1.2 Repair procedures" [4 45].
No Leaks may be found in the refrigerant
circuit. Perform a pressure test of the refrigerant circuit, see "4.2.1 Checking procedures" [4 197].
4 De-activate Heating and activate Cooling operation via the user interface.
5 Check with a contact thermometer (or by touching) if the flow through the 4- way valve corresponds with the flow shown in the flow diagram. (See
"6.3 Piping diagram" [4 227]).
Is the flow correct? Action
Yes 4‑way valve is OK. Return to the
troubleshooting of the specific error and continue with the next procedure.
No Replace the body of the 4‑way valve,
see "3.1.2 Repair procedures" [4 45].
When outdoor temperature does not allow the unit to run in cooling or heating mode
INFORMATION
Follow this procedure when the outdoor temperature is outside the temperature range for one of the operation modes (Heating or Cooling). The unit CANNOT operate in the mode for which the outdoor temperature is outside its temperature range. See the databook on Business Portal for the temperature range of the operation modes.
1 With the unit operating, connect the service monitoring tool to the unit and check whether the unit is operating in Heating or Cooling mode.
2 Check with a contact thermometer (or by touching) if the flow through the 4- way valve corresponds with the flow shown in the flow diagram of the specific operation mode. (See "6.3 Piping diagram" [4 227]).
Is the flow correct? Action
Yes 4‑way valve is OK. Return to the
troubleshooting of the specific error and continue with the next procedure.
No Perform the next step of this procedure.
3 Connect a manifold to one of the service ports of the refrigerant circuit and check the pressure (suction, discharge). Compare with normal operation conditions of the unit.
Refrigerant pressure correct? Action
Yes Replace the body of the 4‑way valve,
see "3.1.2 Repair procedures" [4 45].
No Leaks may be found in the refrigerant
circuit. Perform a pressure test of the refrigerant circuit, see "4.2.1 Checking procedures" [4 197].
3.1.2 Repair procedures
To remove the 4-way valve coil
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Remove the required plate work, see "3.14 Plate work" [4 143].
Prerequisite: If needed, remove any parts to create more space for the removal of the 4‑way valve coil.
1 Remove the screw and remove the 4‑way valve coil from the 4‑way valve body.
a b c A
A Class 20~35 unit a Screw
b 4‑way valve coil c 4‑way valve body
A
c a b
A Class 42~71 unit a Screw
b 4‑way valve coil c 4‑way valve body
2 Cut all tie straps that fix the 4‑way valve coil harness.
3 Unplug the 4-way valve connector from the appropriate PCB.
4 To install the 4‑way valve coil, see "3.1.2 Repair procedures" [4 45].
To remove the 4-way valve body
Prerequisite: Recuperate the refrigerant from the refrigerant circuit, see
"4.2.2 Repair procedures" [4 202].
1 Remove the 4‑way valve coil from the 4‑way valve body, see "3.1.2 Repair procedures" [4 45].
2 Remove and keep the putty (if installed) and the insulation (if installed) for re- use.
3 Supply nitrogen to the refrigerant circuit. The nitrogen pressure MUST NOT exceed 0.02 MPa.
4 Wrap a wet rag around the components near the 4‑way valve pipes. Heat the brazing points of the 4‑way valve pipes using an oxygen acetylene torch and remove the 4‑way valve pipes from the refrigerant pipes using pliers.
a
b a
c A
A Class 20~35 unit a 4‑way valve pipe b 4‑way valve
c Putty
c a b a
A
A Class 42~71 unit a 4‑way valve pipe b 4‑way valve
c Putty
5 Stop the nitrogen supply when the piping has cooled down.
6 Remove the 4‑way valve.
INFORMATION
It is ALSO possible to cut the component pipe(s) using a pipe cutter. Make sure to remove the remaining component pipe end(s) from the refrigerant pipes by heating the brazing point(s) of the component pipe(s) using an oxygen acetylene torch.
7 Install plugs or caps on the open pipe ends of the refrigerant piping to avoid dirt or impurities from entering the piping.
8 To install the 4‑way valve body, see "3.1.2 Repair procedures" [4 45].
To install the 4-way valve body
1 Remove the plugs or caps from the refrigerant piping and make sure they are clean.
2 Remove the 4‑way valve coil from the spare part 4‑way valve body.
3 Install the 4‑way valve body in the correct location and correctly oriented.
Insert the pipe ends in the pipe expansions.
4 Supply nitrogen to the refrigerant circuit. The nitrogen pressure MUST NOT exceed 0.02 MPa.
5 Wrap a wet rag around the 4‑way valve body and any other components near the 4‑way valve and solder the 4‑way valve pipes to the refrigerant pipes.
a
b a
c A
A Class 20~35 unit a 4‑way valve pipe b 4‑way valve c Putty
c a b a
A
A Class 42~71 unit a 4‑way valve pipe b 4‑way valve c Putty
CAUTION
Overheating the valve will damage or destroy it.
6 After soldering is done, stop the nitrogen supply after the component has cooled‑down.
7 Install the putty (if available) and the insulation (if available) in their original location.
8 Install the 4‑way valve coil on the 4‑way valve body, see "3.1.2 Repair procedures" [4 45].
9 Perform a pressure test, see "4.2.1 Checking procedures" [4 197].
10 Add refrigerant to the refrigerant circuit, see "4.2.2 Repair procedures" [4 202].
To install the 4-way valve coil
1 Install the 4‑way valve coil on the 4‑way valve body.
a b c A
A Class 20~35 unit a Screw
b 4‑way valve coil c 4‑way valve body
A
c a b
A Class 42~71 unit a Screw
b 4‑way valve coil c 4‑way valve body
2 Install and tighten the screw to fix the 4‑way valve coil.
3 Route the 4‑way valve coil harness towards the appropriate PCB.
4 Connect the 4-way valve connector to the appropriate PCB.
A mechanical lock is present on the compressor?
Action
No Perform an mechanical check of the
compressor, see "3.2.1 Checking procedures" [4 49].
To perform a mechanical check of the compressor
Prerequisite: First perform an auditive check of the compressor, see
"3.2.1 Checking procedures" [4 49].
Prerequisite: Stop the unit operation via the user interface.
1 Turn OFF the respective circuit breaker.
2 Visually check:
▪ For oil drops around the compressor. Locate and fix as needed.
▪ Pipes for signs of damage. Replace pipes as needed.
3 Check that the compressor bolts are correctly fixed. Fix as needed.
4 Check that the compressor wire terminals cover is correctly installed and fixed. Correct as needed.
5 Check the compressor dampers for any damage.
a
a
1 Damper
INFORMATION
The compressor dampers may look different.
Compressor dampers are in a good condition?
Action
Yes Perform an electrical check of the
compressor, see "3.2.1 Checking procedures" [4 49].
No Replace the compressor and/or
damaged dampers, see "3.2.2 Repair procedures" [4 55].
To perform an electrical check of the compressor
1 First perform a mechanical check of the compressor, see "3.2.1 Checking procedures" [4 49].
DANGER: RISK OF ELECTROCUTION
Wait for at least 10 minutes after the circuit breaker has been turned OFF, to be sure the rectifier voltage is below 10 V DC before proceeding.
2 Remove the cover of the compressor wire terminals.
a A
A Class 20~35 unit
a Compressor wire terminals cover a
A
A Class 42~71 unit
a Compressor wire terminals cover
3 Disconnect the Faston connectors from the compressor wire terminals U, V and W.
INFORMATION
Note the position of the Faston connectors on the compressor wire terminals to allow correct connection during installation.
V U
W U Wire terminal U
V Wire terminal V W Wire terminal W
CAUTION
Before measuring the compressor motor windings resistance, measure the resistance of the multimeter probes by holding the probes against each other. If the measured resistance is NOT 0 Ώ, this value MUST be substracted from the measured winding resistance.
4 Measure the resistance between the compressor motor windings U-V, V-W and U-W.
Result: All measurements MUST be approximately the same.
Unit Compressor Winding resistance value
(at temperature of 20°C)
Class 20~35 M1C 1.89 Ω ± 5%
Class 42~60 M1C 1.114 Ω ± 5%
Class 71 M1C 0.274 Ω ± 5%
Compressor motor winding measurements are correct?
Action
Yes Continue with the next step.
No Replace the compressor, see
"3.2.2 Repair procedures" [4 55].
5 Measure the continuity of the U, V and W wires between the compressor and the PCB. If no continuity, correct as needed, see "6.2 Wiring diagram" [4 216].
6 Connect the Faston connectors to the compressor wire terminals U, V and W
V U
W U Wire terminal U
V Wire terminal V W Wire terminal W
7 Install the compressor insulation.
8 Turn ON the power using the respective circuit breaker.
9 Start the unit operation via the user interface.
10 Wait for – or create condition to operate the compressor.
11 Once the compressor operates, measure the U-V-W inverter voltages. All measurements MUST be the same.
Inverter voltage measurements are correct?
Action
Yes Continue with the next step.
No Perform a check of the appropriate PCB,
see "3 Components" [4 41].
12 Measure the current in each phase U, V and W while compressor is operating.
All measurements MUST be the same.
Compressor motor winding current measurements are correct?
Action
Yes Perform an insulation check of the
compressor, see "3.2.1 Checking procedures" [4 49].
No Preventively replace the compressor,
see "3.2.2 Repair procedures" [4 55].
To perform an insulation check of the compressor
Prerequisite: First perform an electrical check of the compressor, see
"3.2.1 Checking procedures" [4 49].
Prerequisite: Stop the unit operation via the user interface.
1 Turn OFF the respective circuit breaker.
DANGER: RISK OF ELECTROCUTION
Wait for at least 10 minutes after the circuit breaker has been turned OFF, to be sure the rectifier voltage is below 10 V DC before proceeding.
2 Remove the cover of the compressor wire terminals.
a A
A Class 20~35 unit
a Compressor wire terminals cover a
A
A Class 42~71 unit
a Compressor wire terminals cover
3 Disconnect the Faston connectors from the compressor wire terminals U, V and W.
INFORMATION
Note the position of the Faston connectors on the compressor wire terminals to allow correct connection during installation.
V U
W U Wire terminal U
V Wire terminal V W Wire terminal W
4 Set the Megger voltage to 500 V DC or 1000 V DC.
5 Measure the insulation resistance between the following terminals. The measured insulation resistance MUST be >3 MΩ.
▪ U–ground,
▪ V–ground,
▪ W–ground.
Compressor insulation measurements are correct?
Action
Yes Compressor is OK. Return to
troubleshooting of the specific error and continue with the next procedure.
No Replace the compressor, see
"3.2.2 Repair procedures" [4 55].
3.2.2 Repair procedures
To remove the compressor insulation
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Remove the required plate work, see "3.14 Plate work" [4 143].
1 Detach all the strings.
a
d
b c
a String
b Body jacket (outer) c Top insulation
d Secondary (inner) body jacket
2 Open the body jacket.
3 Remove the top insulation from the compressor.
4 Open the secondary body jacket from the compressor.
5 Remove the body jackets from the compressor.
6 To install the compressor insulation, see "3.2.2 Repair procedures" [4 55].
To install the compressor insulation
1 Install the secondary (inner) body jacket on the compressor.
2 Install the top insulation on the compressor.
a
d
b c
a String
b Body jacket (outer) c Top insulation
d Secondary (inner) body jacket
3 Install the (outer) body jacket around the compressor.
4 Properly fit the top insulation in the body jacket.
5 Attach all strings to secure the body jacket.
To remove the compressor
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Remove the required plate work, see "3.14 Plate work" [4 143].
Prerequisite: Remove the compressor insulation.
Prerequisite: Recuperate the refrigerant from the refrigerant circuit, see
"4.2.2 Repair procedures" [4 202].
1 If needed, remove any parts to create more space for the removal of the compressor.
DANGER: RISK OF ELECTROCUTION
Wait for at least 10 minutes after the circuit breaker has been turned OFF, to be sure the rectifier voltage is below 10 V DC before proceeding.
2 Remove the cover of the compressor wire terminals.
a A
A Class 20~35 unit
a Compressor wire terminals cover a
A
A Class 42~71 unit
a Compressor wire terminals cover
3 Disconnect the Faston connectors from the compressor wire terminals U, V and W.
INFORMATION
Note the position of the Faston connectors on the compressor wire terminals to allow correct connection during installation.
V U
W U Wire terminal U
V Wire terminal V W Wire terminal W
4 Remove the compressor thermal protector, see "To remove the compressor thermal protector" [4 66].
5 Remove the putty from the compressor accumulator. Keep for reuse.
6 Supply nitrogen to the refrigerant circuit. The nitrogen pressure MUST NOT exceed 0.02 MPa.
7 Wrap a wet rag around the components near the compressor pipes. Heat the brazing points of the compressor pipes using an oxygen acetylene torch and remove the refrigerant pipes from the compressor pipes using pliers.
a
a A
A Class 20~35 unit a Compressor pipe
a a A
A Class 42~71 unit a Compressor pipe
8 Stop the nitrogen supply when the piping has cooled down.
INFORMATION
It is ALSO possible to cut the component pipe(s) using a pipe cutter. Make sure to remove the remaining component pipe end(s) from the refrigerant pipes by heating the brazing point(s) of the component pipe(s) using an oxygen acetylene torch.
9 Remove the nuts and bolts and remove the compressor from the unit.
b
c a
c A
A Class 20~35 unit a Nut
b Compressor c Damper
b
a
c a
c A
A Class 42~71 unit a Nut
b Compressor c Damper
10 Remove the 3 dampers from the compressor.
INFORMATION
The compressor dampers may look different.
11 Remove the bushings and keep them for re-use.
12 Install plugs or caps on the open pipe ends of the refrigerant piping to avoid dirt or impurities from entering the piping.
13 To install the compressor, see "3.2.2 Repair procedures" [4 55].
To install the compressor
1 Check the state of the dampers. Replace if worn.
2 Install the 3 dampers in the correct location on the unit.
3 Remove the plugs or caps from the refrigerant piping and make sure they are clean.
4 Remove the caps from the compressor pipes (of the new compressor).
CAUTION
The oil in the compressor is hygroscopic. Therefore remove the caps from the compressor pipes as late as possible.
5 Install the compressor on the correct location on the dampers. Properly insert the refrigerant pipes in the pipe expansions of the compressor pipes.
6 Install and tighten the bolts and nuts to fix the compressor to the dampers.
b
c a
c A
A Class 20~35 unit a Nut
b Compressor c Damper
b
a
c a
c A
A Class 42~71 unit a Nut
b Compressor c Damper
INFORMATION
The compressor dampers may look different.
7 Supply nitrogen to the refrigerant circuit. The nitrogen pressure MUST NOT exceed 0.02 MPa.
8 Wrap a wet rag around the compressor pipes and any other components near the compressor and solder the compressor pipes to the refrigerant pipes.
a
a A
A Class 20~35 unit a Compressor pipe
a a
A
A Class 42~71 unit a Compressor pipe
CAUTION
Overheating the compressor pipes (and the oil inside the compressor pipes) will damage or destroy the compressor.
9 After soldering is done, stop the nitrogen supply after the component has cooled‑down.
10 Install the putty on the compressor accumulator.
11 Install the compressor thermal protector, see "To install the compressor thermal protector" [4 68].
12 Connect the Faston connectors to the compressor wire terminals U, V and W
V U
W U Wire terminal U
V Wire terminal V W Wire terminal W
13 Install the cover of the compressor wire terminals.
a A
A Class 20~35 unit
a Compressor wire terminals cover a
A
A Class 42~71 unit
a Compressor wire terminals cover
14 Install the compressor insulation, see "3.2.2 Repair procedures" [4 55].
15 Perform a pressure test, see "4.2.1 Checking procedures" [4 197].
16 Add refrigerant to the refrigerant circuit, see "4.2.2 Repair procedures" [4 202].
Is the problem solved? Action
Yes No further actions required.
No Return to the troubleshooting of the
specific error and continue with the next procedure.
a A
A Class 42~71 unit
a Compressor wire terminals cover
2 Remove the compressor thermal protection with bracket from the compressor.
a b
c
a Compressor thermal protector b Faston connector
c Bracket
3 If in doubt, measure the temperature of the compressor thermal protection.
Result: The temperature MUST be below 85°C.
4 Disconnect the Faston connectors from the compressor thermal protection.
INFORMATION
Make sure that the wiring between the compressor thermal protector connector and the connector on the PCB is properly connected and NOT damaged (check continuity), see "6.2 Wiring diagram" [4 216].
5 Using a hot air gun, carefully heat the compressor thermal protection to slightly above 123°C for Class 20~60 units or 133°C for Class 71 units (compressor thermal protection trips at 117~123°C for Class 20~60 units and 127~133°C for Class 71 units).
6 Disconnect the compressor thermal protector from the intermediate connector and measure the resistance between pins 1‑2.
Result: The contact MUST be open (measured resistance = OL).
7 Let the compressor thermal protection cool down below 85°C (reset temperature is 85~105°C).
8 Again measure the resistance between the pins 1‑2 of the connector of the compressor thermal protector.
Result: The contact MUST be closed (measured resistance = 0 Ω).
Does the compressor thermal protector contact open and close at the correct temperature?
Action
Yes Return to the troubleshooting of the
specific error and continue with the next procedure.
No Replace the compressor thermal
protector, see "3.3.2 Repair procedures" [4 66].
3.3.2 Repair procedures
To remove the compressor thermal protector
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Remove the required plate work, see "3.14 Plate work" [4 143].
Prerequisite: Remove the compressor insulation.
1 Remove the cover of the compressor wire terminals.
a A
A Class 20~35 unit
a Compressor wire terminals cover
a A
A Class 42~71 unit
a Compressor wire terminals cover
2 Remove the compressor thermal protector with bracket from the compressor housing.
a b
c
a Compressor thermal protector b Faston connector
c Bracket
3 Disconnect the Faston connectors from the compressor thermal protector.
4 Separate the compressor thermal protector and the compressor thermal protector bracket.
a b
a Compressor thermal protector b Compressor thermal protector bracket
5 To install the compressor thermal protector, see "3.2.2 Repair procedures" [4 55].
To install the compressor thermal protector
1 Install the compressor thermal protector on the compressor thermal protector bracket.
a b
a Compressor thermal protector b Compressor thermal protector bracket
2 Connect the Faston connectors to the compressor thermal protector.
a b
c
a Compressor thermal protector b Faston connector
c Bracket
3 Install the compressor thermal protector in the compressor housing.
4 Install the wire terminals cover on the compressor.
a A
A Class 20~35 unit
a Compressor wire terminals cover a
A
A Class 42~71 unit
a Compressor wire terminals cover
5 Install the compressor insulation, see "3.2.2 Repair procedures" [4 55].
Is the problem solved? Action
Yes No further actions required.
No Return to the troubleshooting of the
specific error and continue with the next procedure.
1 Disconnect the damper motor connector S400 from the indoor unit main PCB.
2 Measure the resistance between the following pins of the damper motor connector.
Result: The measurements MUST be as shown in the table below.
Pins Measured resistance (Ω)
1-2 139.5~160.5
1-13 1-14 1-15
2-13 279~321
2-14 2-15 13-14 13-15 14-15
Damper motor resistance measurements are correct?
Action
Yes Return to the troubleshooting of the
specific error and continue with the next procedure.
No Continue with the next step.
3 Remove the damper motor, see "3.4.2 Repair procedures" [4 71].
4 Measure the resistance between the following pins of the connector on the damper motor.
Result: The measurements MUST be as shown in the table below.
Pins Measured resistance (Ω)
1-2 139.5~160.5
1-3 1-4 1-5
2-3 279~321
2-4 2-5 3-4 3-5 4-5
Damper motor resistance measurements are correct?
Action
Yes Replace the damper motor wiring
harness, see "3.4.2 Repair 4
Damper motor resistance measurements are correct?
Action
No Replace the damper motor, see
"3.4.2 Repair procedures" [4 71].
3.4.2 Repair procedures
To remove the damper motor
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Remove the required plate work, see "3.14 Plate work" [4 143].
1 Put a small drain pan (or container) under the drain hose.
2 Remove the screw from the fixation bracket and pull the drain hose downwards to remove it from the indoor unit.
a
c
b c c
d e
e f g
a Screw (drain hose) b Drain hose
c Screw (damper motor cover) d Damper motor cover e Screw (damper motor)
f Damper motor
g Damper motor wiring harness
3 Remove the 3 screws and remove the damper motor cover from the indoor unit.
4 Remove the 2 screws to remove the damper motor from the cover.
5 Disconnect the damper motor wiring harness from the damper motor.
6 To install the damper motor, see "3.4.2 Repair procedures" [4 71].
To install the damper motor
1 Connect the damper motor wiring harness to the damper motor.
2 Install the damper motor in the correct location on the damper motor cover.
Fix the damper moto to the cover using the 2 screws.