180
A.85 Signal, flow temperature sensor, secondary circuit
A.85
System characteristics
Limited control of refrigerant circuit
Cause
Signal of flow temperature sensor in secondary circuit
faulty
Measures
Check resistor R for NTC 10 kΩ on the disconnected
plug. Replace sensor if required.
Connection: X15.3/X15.4 on the VCMU refrigerant cir-
cuit controller
A.86 Signal, flow temperature sensor, heating/cooling circuit 1
A.86
System characteristics
Limited room heating, heating/cooling circuit 1
Cause
Faulty signal, flow temperature sensor, secondary cir-
cuit or heating/cooling circuit 1
Measures
Check resistor R for NTC 10 kΩ on the disconnected
plug. Replace sensor if required.
Connection: X4.1/X4.2 on EHCU electronics module
A.87 Signal, flow temperature sensor, heating/cooling circuit 2
A.87
System characteristics
Limited room heating, heating/cooling circuit 2
Cause
Faulty signal, flow temperature sensor, heating/cooling
circuit 2
Measures
Check resistor R for NTC 10 kΩ on the disconnected
plug. Replace sensor if required.
■
Heat pumps with 1 integral heating/cooling circuit:
Connection X1 on ADIO electronics module
■
Heat pumps with 2 integral heating/cooling circuits:
Connection X17.1/X17.2 on EHCU electronics mod-
ule
A.91 Refrigerant circuit temporarily off
A.91
System characteristics
■
The refrigerant circuit is temporarily switched off
■
Room heating and DHW heating only via instantane-
ous heating water heater
■
In conjunction with external heat generator:
Room heating only via external heat generator; DHW
heating only via instantaneous heating water heater
Cause
■
Outside temperature too low for heat pump operation
■
Operation without outdoor unit, for example for
screed drying
■
Fault refrigerant circuit
Measures
No action required
Messages
Warning messages (cont.)
6218234
Diagnosis
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