Viessmann VITOTRONIC 200 Service Instructions Manual page 66

Troubleshooting
Messages
(cont.)
Message
Code/system characteris-
tics
DD Contrl high pressure 2
Compressor stops.
66
Cause
High pressure fault heat
pump 2nd stage (if instal-
led):
■ Air in heating circuit.
■ Secondary pump or
heating circuit pump
blocked.
■ Condenser contamina-
ted.
■ High pressure sensor
faulty.
Measures
Delivered condition:
■ Appliances with pres-
sure sensor:
Jumper installed
between terminals
116.3/116.4. If pressure
sensor is installed, the
signal must be continu-
ously present.
■ Appliances with pres-
sure switch:
No jumper installed
between terminals
116.3/116.4. If pressure
switch has responded,
no signal is present.
■ Vent heating circuit.
■ Check system pres-
sure.
■ Check secondary pump
and heating circuit
pumps.
■ Flush heating circuits.
Note
In rare cases, e.g. during
DHW heating, a high pres-
sure fault can occur.
If this occurs several times
in succession, check heat
pump and parameter set-
tings of refrigerant circuit.