back boiler pilot light problem

dellboy25

The pilot lights up but after keeping finger on button for a while it then goes out after release. BACKBOILER
have changed thermocouple but problem persists.
what else keeps the pilot on? would i have trouble with the gas valve ?
or could it be the thermostat ?
Its a BAXI BERMUDA 552 Backboiler with fire front.
any help would be apreciated,thankyou.
THE VALVE is honeywell type with grey pusbutton

jos22

Can't really help, but if you are now getting desperate try a post on http://www.diynot.com/forums/index.php?sid=f9f8db02b6b81fda91142983fc943d22

derrick

Sounds like the gas valve needs replacing.

rockin_plumber

You are 100% certain it is the correct thermocouple??

And another thing.... the flame if playing on the tip of the thermocouple enough for it to detect it is lit???