Viessmann VITOTRONIC 200 Service Instructions Manual page 156

Diagnosis
Refrigerant circuit
Message Meaning
code
4C Suction gas superheating
―
too high
55 Too little refrigerant
H
■
Electronic expansion
■
valve for suction gas
fully open
56 H Condenser frost risk
57 Electronic expansion
H
valve for refrigerant collec-
tor level control fully open
58 Liquid gas supercooling
―
too high
59 Electronic expansion
S
valve for suction gas su-
perheating faulty
5A Electronic expansion
S
valve for refrigerant collec-
tor level control faulty
5B Charge level in refrigerant
―
collector too low
5D Insufficient hot gas super-
H
heating
65 Charge level sensor of re-
S
frigerant collector faulty
156
(cont.)
Heat pump characteris-
tics
Compressor OFF
Compressor OFF
Compressor OFF
■
Refrigerant circuit rever-
■
sal OFF
Compressor OFF
Compressor remains in op-
eration.
Compressor OFF
Compressor OFF
Compressor remains in op-
eration.
Compressor OFF
Compressor remains in op-
eration.
Measure
Check whether the correct coding
■
card is fitted. To check information,
see "System information".
In the event of recurrence: Have the
■
refrigerant circuit checked by a re-
frigeration engineer.
Check amount of refrigerant. Adjust
■
if necessary.
Check plug at connection J11: See
■
"EEV PCB [4]".
Check stepper motor of electronic
■
expansion valve.
Check hydraulics in the secondary
■
circuit, e.g. whether all shut-off
valves are fully open.
Check secondary circuit flow rate.
■
Check flow and return temperature
■
in the secondary circuit.
Check flow and return temperature
■
sensor in the secondary circuit.
Check amount of refrigerant. Adjust
■
if necessary.
Check temperature sensors in the
■
refrigerant circuit.
Check plug at connection J7: See
■
"EEV PCB [4]".
Check stepper motor of electronic
■
expansion valve.
Check secondary circuit flow rate. If
■
necessary, increase the flow rate.
Check installation position of the liq-
■
uid gas temperature sensor: See "In-
ternal components".
Check resistance value (NTC 10 k
■
at connection J13 (T5) on the EEV
PCB: See "EEV PCB [4]".
Check plug at connection J11: See
■
"EEV PCB [4]".
Check stepper motor of electronic
■
expansion valve.
Check plug at connection J7: See
■
"EEV PCB [4]".
Check stepper motor of electronic
■
expansion valve.
Reduce set flow temperature for sec-
ondary circuit, e.g. by adjusting the
heating curves.
Check hot gas temperature sensor:
See message code "0E".
Check plug at connection J25/J26:
See "EEV PCB [4]". Replace sensor if
necessary.
)
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