Viessmann Vitogas 100 GS1 Series Start-Up/Service Instructions page 22

Troubleshooting Guide
Diagnosis and Correction
Failure
Boiler does not start up (continued)
Completion of 90 sec. safety timing
without the pilot lighting or staying lit
Pilot burner lights but main burner does
not activate
Main burner does not stay on
For fault indication on the boiler control, see technical documentation of boiler control.
22
(continued)
Cause
Vent damper (if applicable) is not
open, vent damper jammed or vent
damper motor has not activated
Power venter operation
malfunctioning (if applicable)
Malfunctioning in 120 V/24 V relay
module assembly (see Fig. 3)
No gas available
Pilot burner does not light.
Gas valve does not open.
Poor ground
Ionization current too low (must be >
1 μA DC and steady)
Main gas valve not opening
Ionization current too low when main
burners are lit
Correction
Ensure unobstructed operation of
vent damper blade or replace vent
damper.
The boiler can be made operative
until the new damper arrives by
H leaving the vent damper in the
"Service" or "Hold Open Damper"
(Effikal) mode by using the
service switch on the damper
motor. Vent damper blade should
stay open and boiler should
operate normally.
Or by
H removing the vent damper,
installing a transitional piece of
vent pipe, disconnecting and
removing vent damper cable from
the 120 V/24 V relay module
assembly. Connect jumper to
terminals 2 (orange) and 3 (yellow)
as illustrated in Fig. 3 on previous
page. Refer to wiring diagrams.
Boiler will operate without vent
damper.
Please note:
The "Effikal" damper can be field
replaced with a similar size "Field
Controls" damper.
Check air proving switch. Refer to
separate power venter manual.
For corrective action refer to flow
chart on following page.
Air in gas train; turn power off and on
to reset ignition control module and
restart burner ignition sequence.
Remove debris in pilot orifice or
drywall dust. Check pilot orifice.
Ensure adequate pilot gas pressure.
Check wires, check 24 V to gas valve
(PV and PV/MV).
Replace ground wire.
Measure ionization current with DC
amp meter for value > 1 μA.
Replace pilot burner or S8600B
ignition module.
Check wires, check for 24 V at MV
and PV/MV; no voltage, replace
ignition module. Replace gas valve.
Excessive draft - check chimney.
Check pilot burner.
Replace S8600B module.