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Extractor fan emptying into chimney stack

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SC

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Aug 25, 2003, 5:30:59 AM8/25/03
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In our new kitchen plan we will have our cooker in the current unused
chimney stack. I know we need a liner to stop build up of grease causing a
fire hazard. However I finding it hard to find information online about
which extractor will be suitable. All sites seem to selling fully
integrated (into a cupboard), or with chimney hoods, but we don't need a
hood as we are keeping the chimney breast as a feature. We want a powerful
one as this will be a living area too.

Any advice on what we need or other points we may not have considered?

Many thanks
Suzanne


Chris Harris

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Aug 25, 2003, 2:24:16 PM8/25/03
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I'm thinking about the same thing.

> In our new kitchen plan we will have our cooker in the current unused
> chimney stack. I know we need a liner to stop build up of grease causing
a
> fire hazard.

How does a liner help prevent a build up of grease?
Do you mean a liner for the whole flue or just for the opening where you
will put the fan.

However I finding it hard to find information online about
> which extractor will be suitable. All sites seem to selling fully
> integrated (into a cupboard), or with chimney hoods, but we don't need a
> hood as we are keeping the chimney breast as a feature. We want a
powerful
> one as this will be a living area too.

I plan on using a hood

SC

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Aug 25, 2003, 3:26:21 PM8/25/03
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"Chris Harris" <chris....@cwfi.co.fk> wrote in message
news:bidkba$81mqk$1...@ID-134007.news.uni-berlin.de...

> I'm thinking about the same thing.
>
> > In our new kitchen plan we will have our cooker in the current unused
> > chimney stack. I know we need a liner to stop build up of grease
causing
> a
> > fire hazard.
>
> How does a liner help prevent a build up of grease?
> Do you mean a liner for the whole flue or just for the opening where you
> will put the fan.

Yes the whole length.
Apparently if there is a special liner off the brick walls you are less
likely to get a chimney fire. The liner is non flammable and grease
build-up in it is less like to cause a house fire. So our architect told
us.

>
> However I finding it hard to find information online about
> > which extractor will be suitable. All sites seem to selling fully
> > integrated (into a cupboard), or with chimney hoods, but we don't need a
> > hood as we are keeping the chimney breast as a feature. We want a
> powerful
> > one as this will be a living area too.
>
> I plan on using a hood
>

We would have to remove the chimney breast and put in a concrete head to
support the fireplace above or remove it the full length of the house. We
would then have to run a vent 16' to the nearest outside wall, so venting up
the chimney makes a lot of sense. I would like to make a feature out of it
like this kitchen from Arena:
http://www.arena-kitchens.co.uk/ranges/popup_html/winchester.htm

dg

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Aug 26, 2003, 12:14:30 AM8/26/03
to
Your Architect is giving poor advice.

It is important to prevent the grease from reaching the fan and
ducting in the first place.

Grease filters stop the fan getting clogged and thus premature wear,
and prevent grease from getting to the flue in the first place. No
liner is going to prevent built up grease catching fire.

Any set up you decide on, should have cleanable, grease pre-filters
before the fan.

If non of the manufacturers have a specific model for your purpose,
then a standard cooker extractor box could be adapted.

dg


"SC" <s...@dontsendmail.com> wrote in message news:<3f4a633a$0$78087$c3e...@news.astraweb.com>...

Chris Harris

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Aug 26, 2003, 5:58:47 AM8/26/03
to

> > How does a liner help prevent a build up of grease?
> > Do you mean a liner for the whole flue or just for the opening where you
> > will put the fan.
>
> Yes the whole length.
> Apparently if there is a special liner off the brick walls you are less
> likely to get a chimney fire. The liner is non flammable and grease
> build-up in it is less like to cause a house fire. So our architect told
> us.
>

I have to agree with DG, I don't see how a liner will prevent any build up
of grease, not even a teflon coated one!. I plan on using a good quality
filtered hood to prevent the grease getting into the chimney. I haven't
chosen one yet so don't ask what one :-)

> >
> > However I finding it hard to find information online about
> > > which extractor will be suitable. All sites seem to selling fully
> > > integrated (into a cupboard), or with chimney hoods, but we don't need
a
> > > hood as we are keeping the chimney breast as a feature. We want a
> > powerful
> > > one as this will be a living area too.
> >
> > I plan on using a hood
> >
>
> We would have to remove the chimney breast and put in a concrete head to
> support the fireplace above or remove it the full length of the house. We
> would then have to run a vent 16' to the nearest outside wall, so venting
up
> the chimney makes a lot of sense. I would like to make a feature out of
it
> like this kitchen from Arena:
> http://www.arena-kitchens.co.uk/ranges/popup_html/winchester.htm

My chimney doesn't have a recessed fire place like that one, but is flat
faced with just a hole where the old Rayburn flue entered about 2m above
floor level so fitting a hood is not a problem for me.

It looks to me as if you could adapt one of those cooker hoods that fit into
the wall units of an off the shelf fitted kitchen. Make sure that the fan
and motor box will fit inside the chimney, make a custom filter box and
shove the whole thing up inside.


Christian McArdle

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Aug 26, 2003, 7:39:04 AM8/26/03
to
>Make sure that the fan and motor box will fit inside the chimney, make
>a custom filter box and shove the whole thing up inside.

I have a similar set up, with range in the chimney. The fireplace has been
widened and heightened. However, the flue stops abrubtly with some
floorboards in the room above.

I was planning just to block off the flue 30cm above the lintel with some
multiboard. My partner is vegetarian, so there won't be much meat cooking
going on.

Do you think I'll need an extractor as well? This would require about 3m of
horizontal ducting above kitchen units and a centrifugal fan. Is it possible
to get concealed centrifugal fans complete with grease filters? I can find
normal centrifugals easily.

Christian.


Chris Harris

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Aug 26, 2003, 8:48:22 AM8/26/03
to

I would always put in an extractor in a modern house, or an old house that
has been modernised. This is because there is not the level of airflow in
that you would find in an old house becase of all the drafts, from windows,
doors, gapped floorboards etc.. not to mention the forced draft caused by
the chimney. Because of all this the smells (aromas if you like!) from
cooking will hang around a lot longer - I think this is enough reason to
install a cooker hood.

From a building maintenence point of view you don't really want all the
moisture that is generated by cooking hanging around in your house either.

Even if you are not cooking meat you will still be using vegetable oils, I
expect, and this is IMHO the main source of the muck that is collected by a
cooker hood.

A hood also takes away some of the excess heat that is generated from
cooking. In general this can make the kitchen too hot or make the AC work
harder than it needs to; so another good reason to install a hood.

The only negatives that I can see are the extra electricity used for the
light and fan, and the draught and cooling effects, minimal.

I'm no expert, these are just my opinions, but I hope that I have been some
help.

Chris


Suz

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Aug 27, 2003, 9:53:46 AM8/27/03
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"dg" <drgr...@hotmail.com> wrote in message
news:19c14f45.0308...@posting.google.com...

> Your Architect is giving poor advice.
>
> It is important to prevent the grease from reaching the fan and
> ducting in the first place.
>
> Grease filters stop the fan getting clogged and thus premature wear,
> and prevent grease from getting to the flue in the first place. No
> liner is going to prevent built up grease catching fire.
>
> Any set up you decide on, should have cleanable, grease pre-filters
> before the fan.

Take that as read. It's a kitchen extractor I'm looking for.

No carbon filters or other filters remove all the grease and over time it
may build up in the flue. Another important point is the steam produced by
cooking. This reacts with the carbons from any old soot and produces an
acid which may leach through the chimney breast and cause brownish stains.
A liner would prevent this. This is well documented on the web.

>
> If non of the manufacturers have a specific model for your purpose,
> then a standard cooker extractor box could be adapted.
>

Anyone know a site that has kitchen extractor boxes without design features
such as a hood?


Suz

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Aug 27, 2003, 10:02:12 AM8/27/03
to

"Christian McArdle" <cmcar...@nospam.yahooxxxx.co.uk> wrote in message
news:3f4b46fe$0$254$ed9e...@reading.news.pipex.net...
This is the sort of thing I'm looking for. I'm certain you can get it as
there was one in a friends house when she moved in.

I think you definitely need a extractor. In short, steam and smells. Will
make for a much more pleasant environment. I don't think it would be a good
idea to have the steam constantly in the chimney breast with nowhere to go,
unless it is well sealed all round to keep damp out.

Can I ask why you blocked the flue off? You need to watch the chimeny
breast above doesn't get damp. If you close up a chimney breast you are
suppose to have a vent to let air circulate and prevent damp. Causes a
horrible draught though.

Suz


Christian McArdle

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Aug 27, 2003, 11:26:01 AM8/27/03
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>This is the sort of thing I'm looking for. I'm certain you can get it as
>there was one in a friends house when she moved in.

The problem is due to lack of space. The available space within the flue for
mounting is a brick's depth, a fairly generous width and about a foot in
height. I think a 100mm hole will also weaken the wall considerably, so
something that can take a smaller bore than the standard 100mm would be
good.

>Can I ask why you blocked the flue off? You need to watch the chimeny
>breast above doesn't get damp.

It wasn't me. The chimney from the kitchen rose through bedroom 3. This was
removed by previous owners as the extension of the upstairs bathroom caused
the chimney to jut out right next to where the door had been moved to. The
chimney stack is now chopped off in the loft space. The chimney in the
kitchen was untouched.

Since I moved in, we have opened out the hole to be big enough for a 90cm
range cooker. (10cm wider and 80cm taller than it was). Looking up what
remains of the flue, we can see the floorboards in bedroom 3 above.
Obviously, we need to block this off more effectively to prevent smells
rising.

The only stagnant air will be between the multiboard and the floorboards,
which are very gappy. I can't see it being much different to a standard
floor cavity, with plasterboard and little ventilation.

>I think you definitely need a extractor. In short, steam and smells. Will
>make for a much more pleasant environment. I don't think it would be a good
>idea to have the steam constantly in the chimney breast with nowhere to go,
>unless it is well sealed all round to keep damp out.

It'll be well sealed. The only thing is that I've never really used kitchen
extractors simply because every single one I've encountered has been a
"recirculating" type (read: completely f***ing useless).

Christian.

Christian McArdle

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Aug 27, 2003, 12:26:23 PM8/27/03
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>You also don't particularly want all that grease in your a/c filters
>or in your a/c - either.

I wish.

Christian.


Suz

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Aug 27, 2003, 1:02:34 PM8/27/03
to
> It'll be well sealed. The only thing is that I've never really used
kitchen
> extractors simply because every single one I've encountered has been a
> "recirculating" type (read: completely f***ing useless).
>
So true. Crappy one in our house put in by previous owner. You might as
well flap a carbon filter in the air for all the good it does.

My mother has a properly vented one and it's great for removing steam, and
therefore humidity on high pressure occasions like Xmas dinner. It's really
powerful. If we get one like that, hubby says we'll have to tie bricks to
No 2 daughter's ankles as she might get sucked out. Poor wee
skinny-ma-link.


dave

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Aug 27, 2003, 6:08:21 PM8/27/03
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Suz

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Aug 27, 2003, 6:51:51 PM8/27/03
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Frank Watson

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Aug 28, 2003, 1:54:01 AM8/28/03
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Does the chimney breast back onto an exterior wall (i.e., not in the
moddle of the building)? If so, why not have the extractor blowing
into a horizontal duct pipe which passes horizontally through the
chimney breast, termonating in a ventillator grille on the exterior of
the building?

Frank

Suz

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Aug 31, 2003, 6:38:18 PM8/31/03
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"Frank Watson" <YamaN...@phoneyaddress.com> wrote in message
news:3f4d9797...@news.cis.dfn.de...

No, it is slap bang in the middle of our party wall with the semi next
door...


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