I went to a house in the Crawley, Sussex, area to provide a quote for a new boiler. The owner has already used us to replace his boiler in his main residence.
While I’m measuring up inside for a new boiler, the tenant said, ‘ Are you going to remove the saucepan?’
I get asked a lot of strange questions when doing a quote visit, but this one had me stumped. Why would I change a saucepan? The tenant had appeared perfectly sane up until that point, so I asked what she meant and was directed outside to look at the boiler flue outlet. Apparently it had been this way for the last 5 years at least.
All the more surprising was the Landlord Safety Certificate I was shown, which had been awarded negligently on the last two consecutive years by the UK’s largest gas company…. clue; They have ‘British’ in their name.
As far as I know it’s still there.
Why is it potentially dangerous?
The flue to a modern boiler is formed of two tubes, one inside the other. The inner one is the boiler exhaust, the gap between the inner and outer tube is the air inlet, which supplies all the boiler air to mix with gas.
It is absolutely imperative that the exhaust fumes aren’t allowed to be drawn in by the air inlet, or the carbon monoxide output of the boiler will rise enormously. Therefore all boiler concentric flues are designed to ‘throw’ the exhaust further afield out of the centre tube, whilst drawing in clean (unvitiated, we call it) air from near the wall.
Flue terminals are tested by the manufacturers in various locations and weather conditions to ensure that their designs work as intended.
As far as I’m aware no-one at Potterton has tested their fan flue with a saucepan fitted around it.