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BG warning undersised ventilation

Postby xpsy » Fri Dec 05, 2008 11:57 am


I've read a previous answer about my problem, but I dont know what size I need to enlarge the hole to, It's about 5 x 8 inches at the moment, do you know the regulation size it should be, I have a back boiler and baxi gas fire in front of it, the room is 11 x 18 feet, by the way this is not a Corgi thing where I need certificate is it, as I thought I could do this myself, the heat output of the gas fire is 3.8 Kw and the boiler is 16 Kw.

Many Thanks.
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Simply Build It

Postby gasmick » Fri Dec 05, 2008 7:58 pm

all ventilation to open flue boilers now must be 90% of the requirements for the boiler in use
i would say that its not a d i y job as it needs to be correct to comply with regs
So use a R G I he can work out the gross input of the boiler and deduct the standard kw allowance for advantitious air, then at least you know it will be safe for you and your familly, and he will have to do the usual smoke tests and spillage tests

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Postby htg engineer » Fri Dec 05, 2008 8:36 pm

Heat input of boiler + heat input of fire
- 7 (adventitious ventilation)
x 5
= size of ventilation required (cm2)

htg engineer
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Postby xpsy » Sat Dec 06, 2008 2:36 pm

Thank you, much appreciated.
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