Repairs; Overview Of Sensors, Drain And Air Vent Valves; Draining The Heat Pump On The Secondary Side; Checking The Sensors - Viessmann Vitocal 350-A AWHO 351.A Series Installation And Service Instructions Manual

Troubleshooting

Repairs

Overview of sensors, drain and air vent valves

M
L
K
H
G
F
E
D
C
B
A
Fig. 70
Refrigerant receiver
A
Drain valve
B
Secondary circuit return temperature sensor
C
Thermostatic expansion valve
D
Temperature sensor EVI
E
Solenoid valve
F
Filter dryer
G
Secondary circuit flow temperature sensor
H
Schrader valve, high pressure side
K

Draining the heat pump on the secondary side

1. Close the on-site BDF valve.

Checking the sensors

For sensor connections to the controller and sensor
■
PCB, see page 46.
■ For the position of the sensors in the heat pump, see
diagram on page.
80
N
O
R
S
T
U
V
Safety high pressure switch
L
Electronic expansion valve (EEV)
M
Manual air vent valve
N
4-way diverter valve
O
High pressure sensor
R
Hot gas temperature sensor
S
Schrader valve, low pressure side
T
Low pressure sensor
U
Suction gas temperature sensor
V
2. Drain the heat pump at the drain valve in the sec-
ondary circuit flow.