viessmann vitodens 100


28 Jun 2009
Reaction score
United Kingdom
A Viessmann vitodens 100 boiler has begun to heat the radiators when on hot water only, causing it take along time,and alot of gas to heat the water to luke warm.
I'm assuming It's the step motor cartridge that's at fault, the question is . How do you remove the step motor cartridge from its housing ,
Iv'e removed the 2 screws but I can't budge it.
Has anyone got any Idea's.
Regards, Pez .
Sponsored Links
Have you considered if the boiler is still under the warrantee?

This Viessman boiler was purchased 20/09/06, so its out of warranty.
It's working perfectly except for this sticking diverter valve, the valve is listed as a step motor cartridge but I'm thinking it can't be removed from it's housing.
Do you think I'm right and it comes as a unit or will it come apart.
yours, Pez.
Sponsored Links
Unscrew the two screws in the horizontal plane, it's only friction holding it in otherwise, and they can be a very tight fit.
  • Thanks
Reactions: pez

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local