Ventilation for an open Flue Boiler - Help needed please

[Jacko]

I'm a scout leader and we've just had a maintenance visit from the gas company. We have an Open Flue Boiler (?) + another gas appliance in our kitchen - we've been told that the ventilation is inadequate and needs improving. Apparently it needs to be 575cm sq (ish) due to legislation changes during last year. They will provide advice but it'll cost and its not cheap, he did say that we could use air bricks but they wouldn't be any good because they don't let suffient air through so we'd need dozens of them for it to be adequate.

Any help regarding type of grills, size of hole etc. would be really appreciated as we are currently unable to run the boiler until its sorted.

Thanks in advance

Jacko

[Owain]

IANEdSirrett :-)

B&Q, Wickes et al all sell 'gas safety vents' which have the sq centimetrage of vent written on the packaging. Buy sufficient to total >575sq cm and fit them.

A quick check on Screwfix suggests that item 14434 size 140x140mm has a free air space of 14,700mm²

They must be stated as suitable for gas ventilator use.

Owain

[cynic]

Look up a ventilator supply specialist (IIRC Fans and Grilles used to have a place in Leeds). Contact them and ask for a price for a weatherproof vent with the spec you have been given. Larger is ok. It is not permitted to have a fine mesh in the vent as they clog with dust but if the suppler is advised it is for a combustion vent they will supply a suitable unit, possibly with a large (bird and vermin proof) mesh incorporated. Go for metal not plastic as vandals have less effect.

[cynic]

Just had a look and you might like to try the following link

[Michael Chare]

575 sq cm is quite a big hole. If you live in a 3-4 bed house, I would suggest that you get a 2nd opinion and ask how nuch is needed for each of the two applainces.

[Dave Liquorice]

A hole over 1/2 a meter each side? Seems a bit OTT to me. How big is this boiler again 2MW?

575sq cm is 57,500sq mm or 240mm per side of an open hole. You need to look for one or more things ventilators that total more than 57500sq mm "free air ventilation". The packaging should have this info on as detailed in another post.

[Dave Liquorice]

You'll need 4 of those... 14700 x 4 =3D 588cm sq.

[Ed Sirett]

I posted a reply to this on Sat but it must have gone missing.

The ultimate info is BS 5440-2.

I'd want to know a lot more about the setu, appliances, makes, types and models. To know if the require ventilation is good.

If you truly need that amount of ventilation then 4 big vents are needed as everyone has said.