Install the app
How to install the app on iOS

Follow along with the video below to see how to install our site as a web app on your home screen.

Note: This feature may not be available in some browsers.

Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws

Tommo25

Gas Engineer
Jan 11, 2016
53
12
8
Derby
Member Type
Heating Engineer (Has GSR)
Viessmann Vitodens 100, won’t ignite,
Checked flue - clear
Condense - ok
Power at gas valve
Fan starts
Electrode sparks

Still not igniting gas in the burner?
Can anyone advise ?

Was thinking maybe condense froze and water backed up and broke electrode but it sparked across fine.

Going back in the morning for further investigation maybe you guys have some ideas?

Thanks
 
Is the gas valve letting Gas pass? Could be the solenoid on the gas valve
I'll second that. I had that problem on mine earlier this year. Two solenoids, one was open circuit. Got one from Solenoids UK, less than £12, for a temporary fix to confirm fault and while waiting for the right one from Italy.
 
  • Friendly
Reactions: Allgoode
Sorry didn’t realise I’d put it public 😱, boiler ok now, changed electrode block and gasket and it lit first time. Not completely sure why as the old electrode seamed to be sparking ok.

Last couple of days had about 8 viessmann all with f4. Most was frozen condense. Got another one with maybe an electrode fault.
 
Does anyone have an idea as to why the new electrode solved the problem, even though the old electrode was sparking fine?

Thanks
 

Official Sponsors of Plumbers Talk

Similar plumbing topics

We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.