On Sat, 11 Sep 2004 20:13:46 +0000, Bob Minchin wrote:


Alan wrote in message ...
My 10-year old boiler (conventional, open flue) has started smelling
of gas when it fires up (and recently set my CO detector off). The
flue and ventillation are all fine. I've checked the input and burner
pressures and gas rate - all spot on.

The flames don't look too good - very yellow and look too big. All the
burners etc. have been properly serviced recently and this hasn't
fixed the problem.

regards,
Alan

Yellow flames indicate insufficient air flow either because the air inlet to
the burner is restricted in some way or the flue is not allowing all the
combustion gasses out. As your CO detector is triggering I would suspect the
latter.
Yellow flames means soot which could well helpblock the flue even more. Do
get this checked out before there are serious consequences.
In the short term you could back off the gas flow until the flames turn blue
again. You will get less heat output but at least it should be safe.

Well the the correct approach is that you EITHER fix it properly: (blue
flames [1], gas pressure at correct setting, gas rate 90-105% of nominal,
flue clear and passes a flow test. ) OR you turn it off.


Whoever checked the boiler over did not do a good job. Either get him back
or use another reputable one to inspect and report the first one to
CORGI.

If the first guy is half decent he will be round pronto 'with tail down'
when you say you have yellow flames from a open flued appliance and the CO
alarm has gone off. There are no more lines of safety left, just
fortuitous ventilation, timing & luck.

TRANSCO will give you an opinion but will (nigh on certain) condemn the
appliance.
HTH

[1] If using a combustion analyser then I'd reckon on CO/CO2 0.003 say.
--
Ed Sirett - Property maintainer and registered gas fitter.
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