Corrective Action; Checking The Outside Temperature Sensor; Check Fuse; Check Fuses In The External Accessories Connection Box - Viessmann VITODENS 200-W Service Instructions Manual

Troubleshooting

Corrective Action

80
(continued)
Vitodens 200-W B2HA 112, 150 Service
Continuous boiler pump operation
When the Vitodens 200 B2HA boiler is switched from a
single boiler operation to a multi-boiler operation, coding
addresses 30:0 may automatically reset to 30:3. This will
result in the boiler pump operating continuously. Verify
that the coding address for each boiler 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 90).

Check fuses in the external accessories connection box

1. Switch OFF the power.
2. Open external accessories connection box and check
fuses F1 and F2 (see wiring diagram on page 90).