Heat-Up Preparations; Action In Case Of The Boiler Overheating; Boiler Water Temperature Has Reached 100 °C - Viessmann VITOLIGNO 300-C Operating Instructions Manual

Boiler operation

Heat-up preparations

Fig.4

Action in case of the boiler overheating

The high limit safety cut-out protects your boiler from
overheating.
Note
Never make adjustments at the high limit safety cut-out
which would result in an exclusion of liability.
Replace faulty components only with genuine spare
parts from Viessmann.
Boiler water temperature has reached 100 °C
High limit safety cut-out
The reset button of the high limit safety cut-out is loca-
ted behind cover of the program unit (see the fol-
A
lowing Fig.).
Note
Any high limit safety cut-out response requires a man-
ual reset.
Triggering the function:
The high limit safety cut-out will respond if the boiler
temperature exceeds 100 °C.
10
1. Check the pressure of the heating system at pres-
sure gauge :
A
The system pressure is too low if the indicator
points to the area below the red field. In this case,
top up with water or notify your heating contractor.
Minimum system pressure: 1.0 bar (0.1 MPa)
2. Check that the vents in the installation room are
unrestricted.
Note
With open flue operation, the combustion air is
drawn from the installation room.
3. Verify that the heating system or the heating water
buffer cylinder is drawing off heat. Open the ther-
mostatic valves on the radiators if necessary.
4. Ensure that all heating flow and heating return shut-
off gate valves are open.
5. Check that all covers on the boiler are closed.
6. Ensure that power is supplied to the boiler.
Note
Notify your heating contractor if the boiler overheats
again after a short time or overheats regularly.
Cancelling the function:
Note
The high limit safety cut-out can only be reset
(unlocked) once the boiler water temperature has
reached approx. 70 °C.