"Seri" wrote in message
ups.com...
Hello all,
just a really quick question that I can't find the answer to
elsewhere. I'm soon going to be installing the new cooker hood and
realised that with the planned position for it the ducting will exit
the exterior wall quite close to where the current condensing boiler
flue exits.

I intend to install gravity vents on the outside of the house to stop
any back draft entering and these vents should only really open when
the hood is in operation. I'm hoping this will cause enough positive
pressure to stop any fume/plume entering back into the house.

Am I right in this? Also, are there minimums for how far another
duct/hole should be from the existing boiler flue?
Thanks for any and all help.

Seri


Never install above, but you can install to the side and below the flue from the
boiler, is the normal rule of thumb. Always try to keep them apart by around
the 500 to 600 mm mark as well, if you can. If you can't obtain this distance
apart, then you need to fit a directional baffle on the vent for the cooker hood
so it turns out away from the direction of the boiler flue.

Self closing flaps don't count on extractor ducting when the are fitted to close
to boiler flues.

Or, you could lift the end of the cooker hood duct way above the height of the
roof and not bother about fitting a fan to it, because of the natural chimney
effect it would create.