Viessmann Vitocal 300-G Installation And Service Instructions Manual page 124

Troubleshooting
Repairs
(cont.)
O Secondary pump (accessory for
type BW 301.A)
P Air vent valve on the secondary side
Q Low pressure sensor EEV
R Suction gas temperature sensor
S Safety high pressure switch
Draining the heat pump on the primary/secondary side
1. Shut off the connection to the heating
network.
Checking sensors
Sensor connections to the controller and
sensor PCB.
Temperature sensors type Ni 500
640
600
560
520
480
440
400
-40 -20 0 20
Temperature in °C
124
T High pressure sensor EEV
U Filter dryer
V Primary circuit return temperature
sensor (heat pump brine outlet)
W Drain valve, primary side
X Hot gas temperature sensor
2. Drain heat pump at drain valve on pri-
mary/secondary side (see
page 122).
For the position of the sensors in the heat
pump, see diagram on page 122.
Capturing element: "Ni 500"
■ Outside temperature sensor (F0)
■ Flow temperature sensor, heating cir-
cuit M2 (F12)
■ Flow temperature sensor, separate
cooling circuit
■ Room temperature sensors
40 60