Vent for back boiler

[OLLIE20]

Air bricks are not ok for a gas vent. The holes go smaller from one side to the other, even with the inside vent correct, it would be classed as At Risk, with an air brick outside

Billhooks. Where did you get that information from?

You did get the bit about the holes tapering from outside to inside right. You calculate the hole size from the smaller side.

Terra Cotta air bricks are ok for permanant air vent.

Just make sure enough holes to get correct vent size or insert more air bricks.

So how do you know which is the smaller size, if the brick is fitted with the big holes outside, you cant measure the inside, are you telling me you presume the size of the holes, Leaving yourself wide open

You can not use Air bricks as a gas vent

http://www.transtools.co.uk/store/p...2580u-vent-sizing-gauge-5mm-10mm.html[/QUOTE]

What a pointless link to a vent probe, yes all gas fitters have them, so are you telling me when you put into a tapered air brick hole you know what size it is on the side in the cavity, erm............. no you dont, you guessing

You cant use them

 

[Stamina]

use these to gauge the minimum hole size in a vent

http://www.reginproducts.co.uk/specialisttools/REGT21

 

[mickyg]

what fire and boiler have you got? the vent requirements will be printed in the manual for the fire. Average for BBUs is around80-90cm2 . A 100cm2 vent is usually fitted as its a standard size for core drilled vent kits and covers almost all BBU sizes.
Air brick vents are ok IF you can measure them, but often you need quite a few as the air through them can be pretty useless. You can knock them out and replace them with a plastic version which is much more suitable.
I buy all my vents from Rytons, good price in bulk.