Could anyone please tell me the problem with this boiler - it's Calor
Gas and has had a new valve fitted to try and solve this problem which
was worse with the old valve.
Sometimes when the boiler first starts up the main burner flame
'roars' and burns yellow, up the back of the boiler I think, causing
overheating. If I switch it off and back on again it usually reignites
and burns normally blue.

On 7 Apr, 08:35, "chrismeg" wrote:
Could anyone please tell me the problem with this boiler - it's Calor
Gas and has had a new valve fitted to try and solve this problem which
was worse with the old valve.
Sometimes when the boiler first starts up the main burner flame
'roars' and burns yellow, up the back of the boiler I think, causing
overheating. If I switch it off and back on again it usually reignites
and burns normally blue.

Gheck VERY carefully that the burner jet mounting plate cork gasket
between this plate and the mounting is intact, the jet mounting is
evenly seated and the four screws are holding it flat. Sounds as
though there may be a weep of gas escaping and forming a secondary
flame outside the combustion chamber back wall. This can and does
happen and often melts off the solder holding the overheat stat wires
in place on older models.
Does the boiler no good at all!

On Sat, 07 Apr 2007 00:35:18 -0700, chrismeg wrote:

Could anyone please tell me the problem with this boiler - it's Calor
Gas and has had a new valve fitted to try and solve this problem which
was worse with the old valve.
Sometimes when the boiler first starts up the main burner flame
'roars' and burns yellow, up the back of the boiler I think, causing
overheating. If I switch it off and back on again it usually reignites
and burns normally blue.

It might be that somehow the gas is being ignited as it comes out of the
injectors not as it emerges from the burner ports.




--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards