Check Blocked Vent Safety Switch; Perform Combustion Analysis - Viessmann Vitogas 100 GS1 Series Start-Up/Service Instructions

Procedures
(continued)
I S
nitial start-up ervice
Vitogas 100, GS1
A (mm)
I S
nitial start-up ervice

19. Check blocked vent safety switch

The blocked vent safety switch is located at the back of the boiler in the draft
hood. In the event of a complete vent blockage the bi-metallic spill switch heats up
due to flue gas spillage and interrupts 24 VAC to the gas control shutting down the
burner. The switch requires a manual reset by pushing in the red button. If the
switch activates, the vent system must be checked inside and out and the blockage
or defect corrected by a qualified heating contractor before the boiler is put back in
operation.
Bottom of blocked vent safety switch
bracket, sensing cup must point upward.
Must line up with bottom
of draft hood skirt
GS1-22 GS1-29 GS1-35
135 181 218

20. Perform combustion analysis

GS1-42 GS1-48 GS1-60
264 310 401
Initial Start-up and Service
1. Disconnect chimney piping from the
draft hood.
2. Cover draft hood chimney connection
in order to test functionality of
blocked vent safety switch.
WARNING
Ensure that windows in the room are
open. Provide proper ventilation.
3. Activate boiler.
The blocked vent safety switch must
deactivate the burners not more than
2 minutes after activation.
WARNING
Never test functionality of blocked
vent safety switch using an open
flame. Direct, intense heat may
damage sensor. A short-circuit or
tripping of the sensor deactivates
burners.
H Check position of switch
blocked vent safety switch requires
more than 2 minutes to deactivate.
H Replace switch or check wiring:
- if blocked vent safety switch does
not deactivate
- if burners do not activate
- if switch is corroded in any way.
4. Deactivate boiler.
5. Uncover draft hood chimney
connection and reconnect chimney
piping to draft hood.
1. For a combustion analysis, please
repeat steps commencing on
page 13.
2. Record measurements and settings
on page 30 of this manual.
3. Reclock burners if necessary.
if
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