Viessmann VITOCAL 300-G PRO Installation And Service Instructions Manual page 104

Troubleshooting
Repairs
(cont.)
wQ Only type WW 302.A125,
WW 302.A155, WW 302.A200,
WW 302.A250, WW 302.A300:
Second parallel filter dryer
wW Condenser
wE Evaporator
wR Primary circuit return temperature
sensor (heat pump brine outlet)
Draining the heat pump on the primary/secondary side
Drain the heat pump at the on-site drain
valve (primary/secondary side).
Checking sensors
Sensor
■ Outside temperature sensor (F0)
■ Flow temperature sensor, heating circuit M2/
HC2 (F12)
■ Cooling circuit flow temperature sensor (di-
rect heating circuit A1/HC1 or separate cool-
ing circuit SKK) (F14)
■ Room temperature sensors
■ Buffer temperature sensor (F4)
■ Cylinder temperature sensor (F6)
■ Flow/return temperature sensor, secondary
circuit (F8/F9)
■ System flow temperature sensor (F13)
■ Boiler water temperature sensor, external
heat generator (F20)
All sensors in the heat pump refrigerant cir-
cuit
104
wT Secondary circuit flow temperature
sensor
wZ Primary circuit flow temperature
sensor (heat pump brine inlet)
wU Flow switch
wI Frost stat
wO Temperature sensor for frost stat
eP Sight glass, if installed
Capturing el-
ement
Ni500
Pt500
Connection/instal-
lation position
see controller and
sensor PCB (see
page 68)
see page 99