Viessmann Vitotronic 200 KW2 Installation And Service Instructions Manual page 44

Troubleshooting
Faults which are not displayed at the programming unit
Boiler water temperature too high or too low
Compare the actual with the set boiler water temperature
H Set value too high or too low →
Check the settings of the time switch, the heating curves and the coding
addresses.
Check the set value adjuster and the remote control unit (if installed):
1. Select a very high day temperature and a very low night temperature.
2. Set the time switch so that in the next few minutes the system will
change from operation with standard room temperature to operation
with reduced room temperature or vice versa.
3. The changeover must effect a significant set value change for the boiler
water temperature.
No noticeable change:
Temporarily connect the remote control unit (incl. base) directly to
Vitotronic and repeat the above test.
Set value now perfect:
The fault lies with the on−site connection with the remote control.
Set value still too high or too low:
Repeat the device setup and remote control checks.
Possibly replace the remote control unit.
4. Check external hook−ups (control module V, Vitocom 100, function
extension 0−10 V).
H Set value OK →
The fault lies with temperature monitoring
1. Establish the boiler water temperature with a thermometer inside the
sensor well.
2. Compare the values from the boiler temperature sensor with the
resistance curve.
3. Check the switch−off point of the electromechanical thermostat.
44
(cont.)