Viessmann VITOCAL 250-A - Page 162

162
F.1056 Faulty relay, inverter intermediate circuit
F.1056
System characteristics
Heat pump off
Cause
Inverter relay faulty
Measures
1. Isolate the outdoor unit from the power supply. Wait
at least 2 min. Switch on voltage again.
2. Replace inverter.
F.1057 Fault, high pressure sensor, refrigerant circuit
F.1057
System characteristics
Heat pump off
Cause
Fault, high pressure sensor
Measures
1. Check voltage U on EHCU electronics module:
■
Terminals X20.1/X20.3: U = 5 V
■
Terminal X20.2: U = 0 to 5 V
2. Replace high pressure sensor if necessary.
F.1074 Pressure differential too low for circuit reversal
F.1074
System characteristics
Refrigerant circuit locked
Cause
Impermissible pressure fluctuations in refrigerant cir-
cuit
Further message: I.129, 3 times
Measures
1. Check 4-way diverter valve: See F.801.
2. Check high pressure sensor: See F.1011.
3. Check low pressure sensor: See F.1012.
4. Check phases of compressor power supply for
clockwise rotating field.
5. Check compressor: See F.1076.
6. Unlock refrigerant circuit via ViGuide.
F.1076 Compressor start count exceeded with oil temperature too low
F.1076
System characteristics
Refrigerant circuit locked
Cause
Compressor thermal overload:
■
Refrigerant circuit pressure too low
■
Viscosity of compressor oil too low
Further message: I.110, 10 times
Measures
1. Check the operating pressure on the secondary
side: Max. 3 bar (0.3 MPa)
2. Check refrigerant lines for mechanical damage.
Refrigerant lines must be connected free of load and
torque stress.
3. Check condenser for mechanical damage. If neces-
sary, purge the condenser.
4. Check refrigerant oil for correct viscosity and
amount. Purge the refrigerant circuit.
5. Check oil sump heater on VCMU refrigerant circuit
controller: See F.1009.
Messages
Fault messages (cont.)
6218234
Diagnosis