Stove with open air supply

vanman99

hi, looking to pick anyones brain. moving into new build, have a 5kw stove with external air supply. The air supply is in but the contractor who installed it has left the flue underneath open so there is cold air pouring into the room, he assures me this is the correct installation and this is how the stove needs to be set up. I think it's nonsense, there is a cover plate that can be fitted but just want to check if anyone knows should I close up flue underneath the stove or as the contractor says leave it open?

my3cents

Come on this has to be a no brainer? If you have a fire in a modern air tight house where does the air come from for it to burn? You can't block the vent because you can't guarantee that anyone using the fire will unblock it first.

The vent is there to stop you dying of carbon monoxide poisoning.

If you want to block the vent up fine remove the stove.

While I'd investigate why the vent is "pouring in" cold air in order to reduce the problem (if the fire is not in yet it will pour air in because of the natural flow of air up the chimney a closed down fire won't create the same pull in from outside and will be using the air as it comes in) you may find the best solution is a stove that is directly connected to the vent so no outside air is pulled into the room.

Forge83

Any picture?
Building regulations states there needs to be an air vent in the room with a solid fuel appliance. It is a safety precaution. It would normally be on the external wall within that room.
The external air supply to the stove is a direct independent supply of air to the stove.it will normally be a 4" pipe directly connected to the lower back or underneath of the stove. There will be a lever on the stove to control this air flow. If this pipe is not connected then this is incorrectly installed.

vanman99

I don't think i explained properly. So i have a stove with an external air supply. The air supply is in connected to the stove, a vent going to the outside world and in to the back of the stove. However there is a flue underneath the stove which could be used to attached the external air, this has been left open and cold air is blasting in to the room. it makes no sense in a modern air tight house to allow the cold air to blast into the house, not exactly air tight.

K.Flyer

If you state the exact make and model, preferably with a picture of the installation, the manufacturers installation manual will say how the air supply needs installed.

exaisle

vanman99 wrote: »

I don't think i explained properly. So i have a stove with an external air supply. The air supply is in connected to the stove, a vent going to the outside world and in to the back of the stove. However there is a flue underneath the stove which could be used to attached the external air, this has been left open and cold air is blasting in to the room. it makes no sense in a modern air tight house to allow the cold air to blast into the house, not exactly air tight.

..and you haven't explained it properly the second time either...

Are you saying that the flue at the bottom is an alternative flue to the flue on the back (the one on the back being connected) so that the air is coming in to the stove and is escaping out the flue at the bottom? If that's the case, then the one at the bottom should be blanked off with the cover plate. The two flues give you an option to connect from either the bottom,or the back.

vanman99

http://www.charnwood.com/files/documents/instructions/Cseries.pdf

Charnwood C Five - See page 20 - 44 & 43 where left off, and i'm being told that's a feature of these new fires in these new houses.... Air intake is coming in at 40.....

exaisle

You have to ask yourself....why did they supply a coverplate if one of the supply ducts was to be left open?

K.Flyer

It says in the installation manual that a permanent room air vent is required, sited in the room in a way that it cannot be blocked.

GY A1

Should that external air supply not be connected directly to the stove !

vanman99 wrote: »

hi, looking to pick anyones brain. moving into new build, have a 5kw stove with external air supply. The air supply is in but the contractor who installed it has left the flue underneath open so there is cold air pouring into the room, he assures me this is the correct installation and this is how the stove needs to be set up. I think it's nonsense, there is a cover plate that can be fitted but just want to check if anyone knows should I close up flue underneath the stove or as the contractor says leave it open?

my3cents

GY A1 wrote: »

Should that external air supply not be connected directly to the stove !

I think the problem is the instructions don't mention that.

The manual only mentions an external supply so from what I can read the OP has a connected air supply and this external supply.

I also believe that an external supply is recommended in houses that are airtight and have a heat recovery system. So I'm guessing the OP has a heat recovery system and that is what is sucking air out of the room pulling cold air in via the external vent? - Just a guess????

dathi

http://www.charnwood.com/range/stove/charnwood-external-air-manifold.aspx

vanman99

That's what i thought, so the air in is all that's needed and the blanking plate should be fitted. Ta

my3cents

vanman99 wrote: »

That's what i thought, so the air in is all that's needed and the blanking plate should be fitted. Ta

Drop an email to Charnwood and ask. Probably OK but instructions about a completely different stove doesn't mean they are relevant for yours.

Also see what happens if the air vent is blocked off when you light a fire before deciding to block it permanently. I can imagine a scenario where everything works fine until you open the fire door and the room fills with smoke.

GY A1

I'd say the duct pipe put in by ur builder should be piped direct to the stove.
Is it done that way.
Other wise there's cold air coming direct into your warm draught proof house

Have u a pic of back of stove with all this

my3cents

GY A1 wrote: »

I'd say the duct pipe put in by ur builder should be piped direct to the stove.
Is it done that way.
Other wise there's cold air coming direct into your warm draught proof house

Have u a pic of back of stove with all this

I think you'll find that has been done already and that we are talking about a second additional vent.

My concern is that its possible if there is a heat recovery system in lieu of vents in the house then there could be a negative air pressure in the room greater than the pull of air up the chimney.

The OP hasn't provided enough information for an answer we don't even know if the stove has been lit yet or if it works?

If its never been lit I'd cover the vent temporarily, close all the house doors and windows then open the stove door and see if cold air comes into the room from the open stove door? If it does repeat with the vent open.

GY A1

I don't think think it's fully connected from the original post.
But only a picture will tell.

my3cents wrote: »

I think you'll find that has been done already and that we are talking about a second additional vent.

My concern is that its possible if there is a heat recovery system in lieu of vents in the house then there could be a negative air pressure in the room greater than the pull of air up the chimney.

The OP hasn't provided enough information for an answer we don't even know if the stove has been lit yet or if it works?

If its never been lit I'd cover the vent temporarily, close all the house doors and windows then open the stove door and see if cold air comes into the room from the open stove door? If it does repeat with the vent open.

Calahonda52

vanman99 wrote: »

That's what i thought, so the air in is all that's needed and the blanking plate should be fitted. Ta

Vanman,

This is the third attempt at explaining what is going one so why not post a few pictures as this matter is way too serious to be summed up by That's what i thought,


You are getting very good advice from others here so before the year ends you might respond with pictures

vanman99

Thanks for the replies folks, will get some pics up later today

my3cents

vanman99 wrote: »

Thanks for the replies folks, will get some pics up later today

Great, can you also give us some details about how the house is provided with ventilation other than these stove vents?

vanman99

Ok, Pic 1 = Stove. Pic 2 = vent pipe from outside to stove. Pick 3 = vent pipe attached to stove. Pic 4 = Blank plate which had been left off and i have now attached to the stove. House has Heat Recovery Ventilation installed.

my3cents

vanman99 wrote: »

....

Ok, Pic 1 = Stove. Pic 2 = vent pipe from outside to stove. Pick 3 = vent pipe attached to stove. Pic 4 = Blank plate which had been left off and i have now attached to the stove. House has Heat Recovery Ventilation installed.

It looks like there were two entry points for air to the stove and the installer should have used one or the other. So it looks to me like there was one pipe attached to the stove and a hole left in the stove that should have been blocked up which you have now done?

The real test is getting the fire going as I suggest earlier.

Edit> I would be a little concerned if cold air came out of the now closed up part of the stove when the stove was set for max air through it because air is being pulled out of the room faster than air is going up the chimney which isn't a good.