Vaillant VCW 242e problem

[mebsk]

Hi, I would be grateful if any one could help me with this.

The boiler will not fire up automaticaly when the CH is switched on, I can hear some sort of whirring noise which I assume is the fan, but no ignition.

If I turn the electric supply to the boiler off & on with the CH thermostat on a high setting then the boiler will ignite and work as normal.

The HW side of the boiler works as it should.

Many Thanks.

 

[bengasman]

Can you post a pic of the machine? I can never remember which is which with those stupid Vailant model names.

 

[mebsk]

Sorry Bengasman, don't no how to upload picture on to post, but I have uploaded an image of the boiler in my album.

Hope that's OK.

 

[bengasman]

This model has a hydro-mechanical switching system for ch/dhw which sometimes needs adjusting. Due to the small bore pipes, they are also kind of sensitive to dirt in the system.
It could be a number of other things, but this is what I would look at first based on your description of the problem.

 

[Andygasman2010]

The servo valve probably isn't returning to rest position fully. This is right at the front, middle of the boiler. Catch the boiler in it's fault state and try pushing the black arm back manually, if the heating fires bobs your uncle!