Corrective Action; Continuous Boiler Pump Operation; Checking The Outside Temperature Sensor; Check Fuse - Viessmann VITODENS 200-W Service Instructions Manual

Vitodens 200-W B2HA 19, 28, 35 Service

Corrective Action

Continuous boiler pump operation

If the Vitodens 200 B2HA boiler is reset, coding addresses
30:0 may automatically reset to 30:3. This will result in
the boiler pump operating continuously. Verify that the
coding address is 30:0. Adjust to 30:0 if necessary.
Refer to page 54.

Checking the outside temperature sensor

1. Pull plug "X3" from the control unit.
2. Test the resistance of the outside temperature
sensor across terminals "X3.1" and "X3.2" on the
disconnected plug and compare it with the curve.
3. Where actual values deviate severely from the curve
values, disconnect the wires at the sensor and repeat
test on the sensor itself.
4. Depending on the result, replace the lead or the
outside temperature sensor. Sensor type: NTC 10 kΩ
Outdoor temperature

Check fuse

1. Switch OFF the power.
2. Release side latches and pivot the control unit down.
3. Remove cover A.
4. Check fuse F1 (see wiring diagram on page 88).

Check fuses in the external accessories connection box

1. Switch OFF the power.
2. Open the external accessories connection box and
check fuses F1 and F2 (see wiring diagram on
page 88).
Troubleshooting
79