Viessmann VITOTRONIC 200 Service Instructions Manual page 155

Refrigerant circuit
(cont.)
Message Meaning
code
27 Compression ratio too
H
high
29 Condensing temperature
H
too high
2B Max. suction gas pressure
H
exceeded
2C Min. pressure differential
H
between high and low
pressure side has not
been reached.
2E Min. required high pres-
H
sure undershot
35 Minimum suction gas tem-
H
perature undershot
3A Safety high pressure
S
switch has responded.
48 Suction gas superheating
―
too low
49 Evaporator max. operating
―
pressure (MOP) has been
reached; changeover from
superheating to pressure
control of the suction gas.
Heat pump characteris-
tics
Compressor OFF
Compressor OFF
Compressor OFF
Compressor OFF
Compressor OFF
Compressor OFF
Compressor OFF
Compressor OFF
Compressor remains in op-
eration.
Measure
Check high and low pressure sen-
■
sors: See message codes "05" and
"0A".
If the pressure sensors are OK but the
fault persists:
Check the position of the operating
■
point: See "Compressor travel"
and/or "Compressor path".
If necessary, reduce the set cylinder
■
temperature.
As for "D4 Control high pressure":
See "Message overview" for the heat
pump control unit.
Check amount of refrigerant. Adjust
■
if necessary.
If fault persists, notify a specialist.
■
Check high and low pressure sen-
■
sors: See message codes "05" and
"0A".
If the pressure sensors are OK but the
fault persists:
Check inverter power connections.
■
Check whether the compressor is
■
still running at a constant speed af-
ter starting: See "Refrigerant circuit
controller [4]". Replace compressor
if necessary.
Check high pressure sensor: See
■
message code "05".
Check amount of refrigerant. Adjust
■
if necessary.
Check amount of refrigerant. Top up
refrigerant if necessary.
Further measures as for "D3 Low
pressure": See "Message overview"
for the heat pump control unit.
As for "C9 Refrigerant circ (SHD)":
See "Message overview" for the heat
pump control unit.
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.
No action required
Diagnosis
155