Viessmann VITOCAL 151-A Installation And Service Instructions Manual page 115

Warning messages
Message code System characteristics
A.75 Unusual operating noise
■
Unusual starting and opera-
■
tional characteristics
A.80 Refrigerant circuit off: Inverter
and compressor cannot be
switched on.
A.81 Performance factor (COP)
■
too low
Compressor output too low
■
Refrigerant circuit off
■
A.82 Unstable control due to faulty
pressure signal
A.83 No DHW heating
A.84 No room heating
A.85 No DHW heating
A.86 No room heating, heating/
cooling circuit 1
A.87 No room heating, heating/
cooling circuit 2
(cont.)
Cause
Pressure spikes in secon-
dary circuit
Fan blocked
Insufficient heat transfer in
evaporator
Fault through internal
monitoring of the pressure
sensors of the affected
CAN bus subscriber
Cylinder temperature sen-
sor signal faulty
Return temperature sen-
sor signal faulty
Cylinder temperature sen-
sor signal faulty
Faulty signal, flow temper-
ature sensor, secondary
circuit / heating/cooling
circuit 1
Faulty signal, flow temper-
ature sensor, heating/cool-
ing circuit 2
Troubleshooting
Measures
Check the expansion vessel.
■
Check the system pressure. Top
■
up with water and vent if re-
quired.
Check outdoor unit for icing up.
■
De-ice if necessary.
Check fans can rotate freely.
■
Check evaporator. Clean if neces-
sary.
Check CAN bus subscribers
■
Check refrigerant circuit control-
■
ler VCMU power supply.
Check electronics module HPMU
■
power supply.
If the message occurs frequently,
■
replace refrigerant circuit control-
ler VCMU and/or electronics
module HPMU.
Check resistance value
(NTC 10 k ). Replace sensor if re-
Ω
quired.
Wall mounted indoor unit:
■
Connection on the underside of
the appliance to 6-pole connec-
tion socket on the right, termi-
nals 9 and 10.
Floorstanding indoor unit:
■
Connection at plug 5 on the
HPMU electronics module
Check resistance value
(NTC 10 k ) at connec-
Ω
tion X4.3/X4.4 of the EHCU elec-
tronics module. Replace sensor if
required.
Check resistance value
(NTC 10 k ). Replace sensor if re-
Ω
quired.
Wall mounted indoor unit:
■
Connection on the underside of
the appliance to 6-pole connec-
tion socket on the right, termi-
nals 9 and 10.
Floorstanding indoor unit:
■
Connection at plug 5 on the
HPMU electronics module
Check resistance value
(NTC 10 k ) at connec-
Ω
tion X4.1/X4.2 of the EHCU elec-
tronics module. Replace sensor if
required.
Check resistance value
(NTC 10 k ) at the sensor input on
Ω
ADIO electronics module. Replace
sensor if required.
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