Viessmann Vitopend 100-W Installation And Service Instructions For Contractors page 44

Troubleshooting
Repairs
(cont.)
20
10
8
6
4
2
1
0,8
0,6
0,4
10 30 50
20 40
Temperature in °C
1. Temperature limiter:
Perform the check if the burner con-
trol unit cannot be reset after a fault
shutdown, although the boiler water
temperature is below approx. 90 °C.
■ Disconnect the leads from the sen-
sor.
■ Check the continuity of the temper-
ature limiter with a multimeter.
■ Remove the faulty temperature lim-
iter.
■ Install a new temperature limiter.
4
■
3
2
1
To reset, briefly turn rotary selector
"tr" clockwise as far as it will go
and then back again. The ignition
process will then repeat.
44
70 90 110
60 80 100 120
5
6
2. Boiler water temperature sensor:
■ Disconnect the leads from the sen-
sor.
■ Check the sensor resistance and
compare it with the curve.
■ Replace the sensor in the case of
severe deviation.
!
Please note
The boiler water tempera-
ture sensor is immersed in
the heating water (risk of
scalding).
Drain the boiler before
replacing the sensor.
3. Outlet temperature sensor (gas
combi boiler):
■ Disconnect the leads from the sen-
sor.
■ Check the sensor resistance and
compare it with the curve.
■ Replace the sensor in the case of
severe deviation.
Danger
The outlet temperature sen-
sor is immersed in the DHW
(risk of scalding).
Drain the DHW side of the
boiler before replacing the
sensor.