My Vaillant VCW GB 242 E Combi Compact Wall Mounted Boiler is failing to ignite when the central heating is switched on. I can hear the fan starting up but when i look in the combustion chamber there is no fire .
The hot water on demand is working fine.
Boiler Water Pressure around 1.5bar.
Can anyone provide any ideas as to the cause of this issue?

lancspne, September 2009

anyone know how to clean out the dhw heat exchanger?

Pete C, December 2011

My Vaillant VCW GB 242 E Combi Compact Wall Mounted Boiler is failing to ignite when the central heating is switched on. I can hear the fan starting up but when i look in the combustion chamber there is no fire .
The hot water on demand is working fine.
Boiler Water Pressure around 2bar.
Can anyone provide any ideas as to the cause of this issue?

Khaled, November 2011

I have the same problem except the hw system is now also not working.

I followed gilo's suggestion and took off the front panel. I can see two rocker switches, one black and one red but they are to the bottom left rather than middle mounted on a cast white metal box compete with a small black button (which has no effect when pushed).

With ch set to run, the red switch is on (glowing) and if I toggle the black switch I can hear the pump start/stop but no flame.

Any other ideas?

Will, October 2009

Thanks for your reply.
This seems to be the issue. I have had the CH working now by pressing the black rocker switch back, at least thats a starting point for me.

lancspne, October 2009

new water valve req. remove front panel front middle is a black rocker switch moves on hw demand put ch on pull this switch back off the metal switch ch will fire. usually just scale from a small leak not letting it seat fully.

gilo, September 2009