Viessmann VITOTRONIC 200 Service Instructions Manual page 167

Refrigerant circuit
(cont.)
Message Meaning
code
2E Min. required high pres-
H
sure undershot
33 Central heating/DHW
H
heating:
Secondary circuit flow
temperature too low
3A Safety high pressure
S
switch has responded.
43 Short circuit/lead break,
S
secondary circuit flow
temperature sensor
(downstream of instanta-
neous heating water heat-
er)
44 Short circuit/lead break,
S
secondary circuit flow
temperature sensor (up-
stream of instantaneous
heating water heater)
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.
4A Evaporation temperature
―
too low
4C Suction gas superheating
―
too high
54 Min. flow temperature pri-
H
mary circuit (brine inlet)
not achieved.
Heat pump characteris-
tics
Compressor OFF
Compressor remains in op-
eration, but does not re-
start.
Compressor OFF
Compressor OFF
Compressor OFF
Compressor OFF
Compressor remains in op-
eration.
Compressor remains in op-
eration.
Compressor OFF
Compressor OFF
Measure
Check high pressure sensor: See
■
message code "05".
Check amount of refrigerant. Adjust
■
amount if required.
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
■
the amount of refrigerant if necessa-
ry.
Check temperature sensors in the
■
refrigerant circuit.
As for "C9 Refrigerant circ (SHD)":
See "Message overview" for the heat
pump control unit.
Check resistance value (NTC 10 k
at connection J21 (T2) of the EEV
PCB: See "EEV PCB [4-6] / [4-7]".
Check resistance value (NTC 10 k
at connection J21 (T1) of the EEV
PCB: See "EEV PCB [4-6] / [4-7]".
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
Check primary pump.
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 primary circuit flow rate.
Diagnosis
)
Ω
)
Ω
167