Daikin VRV IV+ Service Manual page 118

2 | Troubleshooting
Service manual
118
Trigger
Thermistor located inside
the power module of the
inverter PCB for
compressor detects a
temperature higher than
a certain value.
To solve the error code
INFORMATION
It is recommended to perform the checks in the listed order.
Prerequisite: Stop the unit operation via the central controller.
1 Turn OFF the respective circuit breaker.
DANGER: RISK OF ELECTROCUTION
Confirm the rectifier voltage is below 10 V DC before proceeding, see
rectifier voltage" [
2 Check that the thermal interface grease is applied properly on the (PCB or
refrigerant piping) contact surface of the heat sink. Adjust if needed.
Possible cause: Thermal interface grease NOT applied properly on the heat
sink.
3 Check if heat sink plate is correctly fixed with screws.
Possible cause: Heat sink plate not correctly installed.
4 Check (by touching) if refrigerant is flowing through the radiant cooling
refrigerant circuit. The radiant cooling refrigerant circuit should be warm if
refrigerant is flowing. If no refrigerant flow, perform a check of the liquid
cooling expansion valve, see
Possible cause: No refrigerant flow through the radiant cooling refrigerant
circuit.
5 Perform a check of the liquid cooling expansion valve. See
4
valve" [ 244].
Possible cause: Faulty liquid cooling expansion valve.
6 Check ambient temperature. Check if outdoor unit location temperature
differs drastically.
7 Check if there is discharge air by-pass on installation location.
Possible cause: External noise. Check further on how to eliminate external
factors.
8 Perform a check of the inverter PCB A6P. See
Possible cause: Faulty inverter PCB A6P.
INFORMATION
If all procedures listed above have been performed and the problem is still present,
contact the helpdesk.
Effect
Unit will stop operating.
4 356].
"3.7 Expansion
Reset
Manual reset via remote
controller.
Outdoor unit power reset.
"To check the
4
valve" [ 244].
"3.7 Expansion
4
"3.10 Inverter PCB" [
REYQ8~20+REMQ5U7Y1B
VRV IV+ Heat Recovery
ESIE18-15B – 2020.05
274].