Sammer1_uk wrote:
I have changed the thermocouple, made sure the boiler was clean and
checked the jets. However none of them seems to of helped. I have
managed to get the pilot to hold once but when I have then switched
the CH on it just clicked and the back boiler didnt come to life.
Before when the CH was switched on there would be a sort of whooshing
noise then the back boiler would ignite. I dont know what to do next.
I have also searched the net for spares for the make of back boiler
but to no avail, can any one help me here, please.

Thanks for your help so far gents.

Look forward to your response.

Craig

If you're sure the thermocouple is ok for your boiler and it working, then
it sounds as though the gas valve may be faulty.
I don't know these boilers but it proberly works like this...
The thermocouple, when up to temp, will latch on the gas valve to keep it
on, thats why you have to hold it in for some time.
Then the main part of the gas valve will open when there is demand voltage
on it.
The click sound may be the gas valve trying to work.
The whoosing noise is the initial ignition of the main burners.
It also possible that there may be some muck in the gas inlet at the boiler.
Often there is a small strainer in there.
If it is the gas valve there are only a few makes of those used by most
boiler manufacturers.
Changing one of these is not for the faint hearted though..

The people at http://www.cetltd.com may be able to help.