Viessmann VITOCAL 151-A Installation And Service Instructions Manual page 114

Troubleshooting
Warning messages
Message code System characteristics
A.16 Refrigerant circuit off: Inver-
■
ter and compressor cannot
be switched on.
Instantaneous heating wa-
■
ter heater is switched off.
The instantaneous heating
water heater will not start.
A.17 No increased DHW hygiene
A.21 The safety valve in the indoor
unit has opened.
A.62 No scanning possible for sec-
ondary pump/heating circuit
pump, heating/cooling cir-
cuit 1
A.63 No scanning possible for
heating circuit pump, heating/
cooling circuit 2
A.65 No room heating/cooling,
heating/cooling circuit 2
A.66 Secondary pump/heating cir-
cuit pump, heating/cooling
circuit 1 not running.
A.68 Heating circuit pump, heat-
ing/cooling circuit 2 not run-
ning.
A.70 Flow rate too low
A.71 Insufficient compressor out-
put
A.72 Insufficient compressor out-
put
A.73 Insufficient compressor out-
put
A.74 Unusual operating noise
■
Unusual starting and opera-
■
tional characteristics
114
(cont.)
Cause
Minimum flow rate under-
shot
■
■
Hydraulic system pressure
too high
Lead break, PWM signal,
secondary pump/heating
circuit pump, heating/cool-
ing circuit 1
Lead break, PWM signal,
heating circuit pump, heat-
ing/cooling circuit 2
Heating circuit pump,
heating/cooling circuit 2
running dry.
No PWM signal, secon-
dary pump/heating circuit
pump, heating/cooling cir-
cuit 1
Incorrect circulation pump
installed
No PWM signal, heating
circuit pump, heating/cool-
ing circuit 2
Incorrect circulation pump
installed
Filter in ball valve of out-
door unit is contaminated
Excess current on com-
pressor
Current of power factor
correction filter too high
Frequency deviation be-
tween actual and set com-
pressor speed
Pressure drop in secon-
dary circuit
Temperature for in-
creased DHW hygiene
is not reached.
DHW cylinder volume
may be too large
Measures
Check secondary pump/heating
■
circuit pump, heating/cooling cir-
cuit 1.
Check flow sensor.
■
Set period for increased DHW
■
hygiene to fall on a period with
low DHW demand.
Check DHW cylinder sizing.
■
Check the expansion vessel.
Isolate the system from the power
supply. Restart the system.
If the message remains displayed,
replace secondary pump/heating
circuit pump, heating/cooling cir-
cuit 1.
Isolate the system from the power
supply. Restart the system.
If the message remains displayed,
replace heating circuit pump, heat-
ing/cooling circuit 2.
Fill system and vent.
Use only spare parts supplied or
approved by Viessmann.
Use only spare parts supplied or
approved by Viessmann.
Clean the filter in the outdoor unit
ball valve.
If message occurs frequently,
check compressor.
If message occurs frequently,
check inverter.
If message occurs frequently,
check compressor.
Check the expansion vessel.
■
Fill system and vent.
■