Checking Sensors - Viessmann Vitocal 300-A Installation And Service Instructions For Contractors

Repairs
(cont.)
Q Suction gas temperature sensor
(downstream of evaporator)
(NTC 10 kΩ)
R Filter dryer
S Schrader valve, low pressure side
T Suction gas temperature sensor
(upstream of compressor)
(NTC 10 kΩ)
U Refrigerant collector
Draining heat pump on the secondary side
1. Close the on-site boiler drain & fill
valve.

Checking sensors

■ Sensor connections to the controller
and sensor PCB: See page 33.
■ Position of the sensors in the heat
pump: See diagram on page 80.
V Intermediate injection solenoid
valve
W Liquid gas temperature sensor
(downstream of refrigerant collec-
tor) (NTC 10 kΩ)
X Schrader valve, high pressure side
Y Refrigerant collector fill level sen-
sor
2. Drain heat pump at drain valve: See
chapter "Overview of internal compo-
nents".
Troubleshooting
81