Chimney Flue for Extract Fan

[Scobalob]

Hi Guys and the compliments of the season to you,
I'm having a ponder - when we had our new kitchen fitted I was well aware that the cooker extract fan wouldn't be ducted to the outside as we'd have to knock through the two (brick) walls and cavity. At the time

I said that we do with the re-circulating fan. For us, this hasn't been a good idea and I am now considering venting externally again.

However, adjacent to the extract fan I have found a clear, sound, slightly sooty, disused chimney (It may have been used on an old solid fuelled cooker) - it would make life a lot easier if I could utilise this rather than run 2m of ducting and bang holes in two walls.

So, the question is - good idea or bad idea?
If its good idea then are there any known regulations involved, do I need to line the chimney with stainless steel (that makes it expensive)...etc...etc?

[tezestwing]

Hi compliments to you to, and I would guess it would be a good idea after all it was used as a basic vent, when it was made redundant was a low level vent fitted to allow air flow up you may need to reinstate this then use a smoke test to make sure the chimney draws, then knock through to fit ducting or sweep to clean, but I think you may need to keep the low level vent to aid the flow hth Tez

[buildersmate]

Drawing of the flue is not an issue because you are not shoving carbon dioxide, carbon monoxide ot other noxious gases up there. All you are after is a place to vent away water vapour and air.
What is likely to be more of a problem is if the water-laden air condenses on the sides of the chimney and drips water down the sides. Provided the (small amounts) of water can drip down the chimney, past the outlet from the vent, into the base of the old chimney, that should be fine.
It's a great idea to re-use it in this way.