Vitodens 100-W Cycles But Won't Ingite, No Error Message

Jake48

My 2007 Viessmann Vitodens 100-W30 cycles continuously but won't ignite. There is no error message. This is the first time I have had a problem with this unit in which there was no Fault Code (error message).



In past I had stuck flapper in 2010 but got F-5 fault.



In 2011 I had low pressure from bad feed reg valve but got Low pressure fault.



The pressure is fine this time.



Is it a stuck flapper again? Is so, why no error message?



Anyone know what might be wrong?

CMadatMe

Flow Switch

Generally you would not see an error code if you're not making the flow switch or the boiler is air bound.

Jake48

Flow Switch

Can you elaborate, I don't know what you mean?



I just got off the phone with Viessmann tech service and they think it is the gas valve.

CMadatMe

There's A

Flow switch in the boiler. If you don't make the flow switch the boiler will just sit there and do what it's doing. No flow no go. That would be the 1st thing I check. Here's the service and install manual..



http://www.viessmann-us.com/content/dam/internet-ca/pdfs/doc/wb1/vitodens_100_is.pdf

Jake48

No Flow Switch

There is no part in the manual called "flow switch"

CMadatMe

Sure there is

Page 73 Part# 33



http://www.viessmann-us.com/content/dam/internet-ca/pdfs/doc/wb1/vitodens_100_is.pdf

Jake48

New Clue

Ok Chris found the pressure switch and when I cycled on felt water flowing through so not that. However, I realized when it cycles, it is actually heating up raising the unit temp from 75 to 82 then shuts off. So that means it is actually firing and lighting, correct?



So why does it keep shutting down?

CMadatMe

Suggest

You call a professional. Didn't say pressure switch, said flow switch