The boiler does not ignite when in auto mode in either CH or DHW. The lockout indicates and when it is reset, the boiler fires up ok in both modes. The c/over valve makes the microswitch and some part of the sequence happens as I can hear the boiler "clicking" after the microswitch is made. I have changed the diaphragm as this seems to be a common problem, but to no avail. Everything seems to work ok after it has been reset, but when switched off, it won't go through the ignite sequence if left for a few hours. Any ideas please?

Peter, May 2007

My boilers still in the same situation, it will run, but only with the aforementioned switching off/on. I've decided to get by for this winter and replace the boiler in the summer with something a little more robust and reliable!!

Peter, February 2008

My boiler is doing the same, we are all freezing (kids are thinking of this as an adventure with double quilts etc!!!). Havent got much money, can you tell me how much we are roughly looking at please

deb6783, November 2007

Sorry I haven't answered before now John but no. i've not had the unit fixed properly. It will fire up manually but I expect the missus will nag me to get it done before the winter comes in. Looks like the main valve will have to be changed again as this cured the fault last time temporarily (thev/v was an overhauled one).

Peter, August 2007

Hi Peter,

Have you had the problem fixed? What was the solution?
My boiler is showing the same symptoms, and so I would
be grateful for any info.

Thanks,

John

John, June 2007

Thanks T.h.s, feared that might be the case.

Peter, May 2007

It's gone beyond a d.i.y fix. THe fault you describe is an ignition lock-out or a safety lock-out and involves the gas and ignition systems. You need an engineer who is familiar with vaillant boilers..

T.h.s, May 2007