Viessmann Vitocal 350-A Installation And Service Instructions Manual page 166

Troubleshooting
Repairs
(cont.)
Draining the heat pump on the secondary side
1. Close on-site drain & fill valve.
Checking sensors
For sensor connections to PCB 3 see
page 212.
Temperature sensors type Ni 500
640
600
560
520
480
440
400
-40 -20 0
Temperature in °C
166
40
20 60
2. Drain heat pump at secondary flow
drain valve.
For the position of the sensors in the heat
pump, see figure on page 165.
Capturing element: "Ni 500"
■ Outside temperature sensor (F0)
■ Flow temperature sensors, heating cir-
cuits M2, M3 (F12)
■ Room temperature sensors (Vitotrol)