Viessmann VITOCAL 151-A Installation And Service Instructions Manual page 117

Warning messages
Message code System characteristics
A.101 Refrigerant circuit operation
impaired
A.102 Refrigerant circuit operation
impaired
Further messages
Note
The possible messages vary according to the system
equipment. Therefore, not all messages will come up
for every system.
Service messages
Message code
P.1
P.4
P.8
P.34
Status messages
Message code
S.60
S.74
S.75
S.94
S.95
S.96
(cont.)
Cause
Values for hot gas temper-
ature in relation to hot gas
pressure not plausible
Values for suction gas
temperature in relation to
suction gas pressure not
plausible
Meaning
Service due after interval.
Top up heating water.
Service due after hours run.
Maintenance of hydraulic filter strainer necessary
Meaning
Summer mode active (outside temperature economy function)
Heating suppression, heating
DHW circulation pump active
No demand, external hook-up, heating/cooling circuit 1
No demand, external hook-up, heating/cooling circuit 2
No demand, external hook-up, heating/cooling circuit 3
Troubleshooting
Measures
Check sensors. Replace both sen-
sors if required.
To check the high pressure sen-
■
sor, measure the voltage at con-
nection X14.1 to X14.3 of the
VCMU refrigerant circuit control-
ler (0 to 5 V).
To check the hot gas tempera-
■
ture sensor, check resistance
value (NTC 10 k ) at connec-
Ω
tion X14.9/X14.10 of the
VCMU refrigerant circuit control-
ler.
Check sensors. Replace both sen-
sors if required.
To check the low pressure sen-
■
sor, measure the voltage at con-
nection X14.4 to X14.6 of the
VCMU refrigerant circuit control-
ler (0 to 5 V).
To check the suction gas temper-
■
ature sensor, check resistance
value (NTC 10 k ) at connec-
Ω
tion X14.7/X14.8 of the
VCMU refrigerant circuit control-
ler.
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