On Sun, 17 Apr 2011 22:07:46 +0100, Steve Walker wrote:

I don't know about this particular boiler, but I've often wondered
whether there is any great risk to poor combustion with most boilers
these days, as they are generally room sealed and under negative
pressure due to the exhaust fan, therefore they should be unable to leak
CO into the room.

It's not as dangerous as with a non-room-sealed type but it's still
putting CO into the atmosphere outside which can - given
prevailing wind conditions - get back into the house. Or a neighbours'
house.

There was a case recently where a boiler had been installed with its flue
close to a window, which had been screwed shut to prevent Products Of
Combustion (POCs in the trade) getting into the room. Then the owner of
the building had the window replaced, with one which had normal openers,
and the occupant of the room died of CO poisoning. (IIRC the boiler was
also badly malfunctioning - you wouldn't expect it of a normally-
operating boiler.)

And, more innocuously, I got called out a few months ago, when it was
freezing cold, to a house where a CO alarm in a room with a boiler had
gone off. The boiler seemed fine - burning cleanly (as measured on the
Flue Gas Analyser, and visual inspection - certainly no sign of sooting).
It was an upstairs room. No sign of any way gases from the cooker
downstairs could have got up to trigger the alarm. But the CO alarm was
next to a vent to outside, and I can only think that a car had been
idling outside for a while, with the engine running to warming up/keep
warm while waiting for someone, and the exhaust gases drifted up in the
cold still air and found there way in through the vent to the alarm.

--
John Stumbles -- http://yaph.co.uk

87.5% of statistics are made up