Viessmann VITOLIGNO 300-C Installation And Service Instructions Manual page 134

Maintenance
Fuses
Installation position, see page 185.
F10
■ 10 A (slow)
■ 250V 50/60 Hz
KSK PCB power cable
■
F20
■ 5 A (slow)
■ 250V 50/60 Hz
■ ZPK PCB power cable
Checking the fuses
1. Switch OFF the power supply.
2. Open the control unit.
Battery
The battery serves to save the time and date in the
event of a power failure.
Installation position, see page 185.
High limit safety cut-out
The high limit safety cut-out is part of the boiler. The
high limit safety cut-out is located behind the boiler
programming unit.
Triggering the function
If the boiler water temperature exceeds 95 °C, the high
limit safety cut-out responds.
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.
134
F30
■ 5 A (slow)
■ 250V 50/60 Hz
HKK PCB power cable
■
3. Check the fuses. Replace if necessary (see con-
nection and wiring diagram).
Danger
Using the wrong fuses or inserting them
incorrectly can lead to an increased risk of
fire.
Do not use force to insert the fuses. Posi-
■
tion the fuses correctly.
■ Only use structurally identical types with
the stated response characteristics.
■ Button cell, type CR2032, 3 V
Replacement: Every 5 years
■
Note
The high limit safety cut-out can only be reset man-
ually.
!
Please note
If this function is not reset, it inhibits the safety
equipment function and can result in system
damage.
Whenever the high limit safety cut-out has been
triggered, check afterwards that the thermally
activated safety valve is reset.