May be due toDescriptionAlarm text on the dis-
play
Alarm
no.
- Open-circuit or short-circuit on sensor inputSensor fault, outdoor temperature sensor in
AMS 10 (Tho-A).
Sensor fault Tho-AE38
- Sensor does not work (see "Temperature
sensor" section)
- Defective control board in AMS 10
- Open-circuit or short-circuit on sensor inputSensor fault, hot gas in AMS 10 (Tho-D).Sensor fault Tho-DE39
- Sensor does not work (see "Temperature
sensor" section)
- Defective control board in AMS 10
- Insufficient air circulation or blocked heat ex-
changer
The high pressure switch (63H1) deployed 5
times within 60 minutes or for 60 minutes con-
tinuously.
HP alarmE40
- Open circuit or short circuit on input for high
pressure switch (63H1)
- Defective high pressure pressostat
- Expansion valve not correctly connected
- Service valve closed
- Defective control board in AMS 10
- Low or no flow during heating operation
- Defective circulation pump
- Defective fuse, F(4A)
Could occur when 15V power supply to the in-
verter PCB is unstable.
When IPM (Intelligent power module) displays
FO-signal (Fault Output) five times during a 60-
minute period.
Power transistor too hotE41
- Incoming power supply interferenceVoltage from the inverter outside the paramet-
ers four times within 30 minutes.
Inverter errorE42
- Service valve closed
- Insufficient amount of refrigerant
- Compressor fault
- Defective circuit board for inverter in AMS 10
- Open-circuit in connection between boardsCommunication between circuit board for in-
verter and control board broken.
Inverter errorE45
- Defective circuit board for inverter in AMS 10
- Defective control board in AMS 10
- Sudden power failureOvercurrent, Inverter A/F moduleInverter errorE47
- The fan cannot rotate freelyDeviations in the fan speed in AMS 10.Fan alarmE48
- Defective control board in AMS 10
- Defective fan motor
- Control board in AMS 10 dirty
- Fuse (F2) tripped
- Open circuit or short circuit on input for low
pressure transmitter
Too low value on the low pressure sensor 3
times within 60 minutes.
LP alarmE49
- Defective low pressure transmitter
- Defective control board in AMS 10
- Open circuit or short circuit on input for suc-
tion gas sensor (Tho-S)
- Faulty suction gas sensor (Tho-S)
- Defective fan motorContinuous deviation on power transistor for
15 minutes.
Inverter errorE51
- Defective circuit board for inverter in AMS 10
63NIBE™ SPLIT ACVM 270
Miscellaneous
Alarm list