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Andrew Smith
Andrew Smith, HVAC Technician
Category: HVAC
Satisfied Customers: 3757
Experience:  Heating and Controls engineer
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My house is grade 2 listed of about 300. When I bought it

Customer Question

My house is grade 2 listed of about 300. When I bought it was bought it had a floor standing gas boiler with a vertical flue of about 20 feet through the roof of the house.
The replacement boiler was fitted by a corgi registered engineer in 2008. The most
practical flue option was thought to be that the new 4" flue should be inserted within the
old galvanised flue. This was accepted as 'unusual' but, if anything, had added safety by
having an additional skin.
The original engineer is no long available and the new man has issued an 'at risk' notice in
respect of the flue. I am told legislation requires all flue joints to be available for inspection.
Is it possible for a flue pressure test to done on the flue?
Submitted: 4 years ago.
Category: HVAC
Expert:  Andrew Smith replied 4 years ago.
At Risk means it may go wrong, so it should still be on and working. This rule is for safety but it is a nightmare, I had a problem with a flue that ran through a ceiling void to get to the outside in a flat - now there is an access hatch every meter so it can be checked every year!
Your plumber should have fitted a chimney flued boiler and used a one piece flue liner, but it is done now.
No easy way out of this because it is through the centre of the old flue, perhaps you can pull the old flue out and knock an access every meter through the chimney breast?
Thinking out loud, this flue would be unsupported too as there are no clips on it?
Customer: replied 4 years ago.

In fact only 4x1000mm flue pipes were purchased + a bend before exiting

the roof. The pipes were secured top and bottom of 4 metre run therefore

only three joints involved.

Is a pressure test not practical?

Expert:  Andrew Smith replied 4 years ago.
For a pressure test you would have to get on the roof and blank the two concentric flue ways somehow and then disconnect at the bottom and test also.
If you were going to go to that trouble you may as well disconnect at the bottom and lift the whole flue out and physically look at the flue seals and then tape them up before putting it back.
Expert:  Andrew Smith replied 4 years ago.
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