Blocking an air vent, issues?

Leif

I have a sitting room with a fireplace that now holds a wood burning stove, a Charnwood C-Four, with less than 5kW output. It does not need a vent. The room has a vent, basically a plastic tube bridging the air gap, with a grill on the inside and a downward facing cowl on the outside. Clearly it was there for the open fire that no longer exists. It was drawing in a lot of cold air, so I shoved a plastic bag inside to shut off the air flow. Would there be any problems with this? I did notice that when I had the kitchen extractor fan on, I was unable to start the stove, the smoke went into the room, clearly the extractor was drawing from the stove flue. I'm surprised I've never heard this mentioned elsewhere.I've not had the extractor running after starting the fire, so I'm not sure what would happen then. The stove is just for taking the chill off the house on a particularly cold evening rather than the main heating appliance. It is also a backup in case the heating fails.

Swipe

Get a vent cover that slides open and shut, then just open the vent when you use the stove and extractor fan..

Greenfires

Plenty of stuff about extractor fans in Part J of the Building Regs.

hethmar

We have had customers who have commercial premises and the kitchen extractors do cause a lot of problems to the fires in other parts of the premises.

Make sure you have a carbon monoxide monitor in the room

southcoastrgi

you can't hide in here (rather than posting your question where it should have been) hoping not to get ridiculed

suki1964

Leif wrote: »

I have a sitting room with a fireplace that now holds a wood burning stove, a Charnwood C-Four, with less than 5kW output. It does not need a vent. The room has a vent, basically a plastic tube bridging the air gap, with a grill on the inside and a downward facing cowl on the outside. Clearly it was there for the open fire that no longer exists. It was drawing in a lot of cold air, so I shoved a plastic bag inside to shut off the air flow. Would there be any problems with this? I did notice that when I had the kitchen extractor fan on, I was unable to start the stove, the smoke went into the room, clearly the extractor was drawing from the stove flue. I'm surprised I've never heard this mentioned elsewhere.I've not had the extractor running after starting the fire, so I'm not sure what would happen then. The stove is just for taking the chill off the house on a particularly cold evening rather than the main heating appliance. It is also a backup in case the heating fails.

Where I work the kitchen extractors are always pulling the smoke from the fire back down and choking everyone.

We open a wee top window between the kitchen and fre to stop this and once the fire is going well its not a problem

southcoastrgi

suki1964 wrote: »

Where I work the kitchen extractors are always pulling the smoke from the fire back down and choking everyone.

We open a wee top window between the kitchen and fre to stop this and once the fire is going well its not a problem

then you need to get this sorted ASAP as there is clearly a prob with the fire before someone dies, opening a window is not the answer

reeac

Leif wrote: »

I have a sitting room with a fireplace that now holds a wood burning stove, a Charnwood C-Four, with less than 5kW output. It does not need a vent. The room has a vent, basically a plastic tube bridging the air gap, with a grill on the inside and a downward facing cowl on the outside. Clearly it was there for the open fire that no longer exists.

I'm not familiar with the Charnwood C-4 but assume that it's a regular wood burning stove in which case it will need a supply of air as did the open fire. Are you assuming that being only 5kW ita air requirements are too small to need a vent? Our Clearview 5 kW stove has an underfloor air vent which was constructed when the bungalow was built which is the ideal way to do it but in an existing house it's all more difficult. Is there an external wall adjacent to the stove? Is it possible to box in an air duct from the present air supply?

alleycat`

The regs for a "under 5kw" stove are that it doesn't require an air brick or additional supply of air, except for certain houses that have very good insulation.

So if we say that modern homes require the air brick, for simplicity, the reality is that the amount of air required v's the size of the smallest commercially available air brick is an issue (to me).

The airbricks I've seen available all appear to be universally much larger than is required.

I know the one i have, air brick, is much larger than is necessary for my "nominally" 5kw stove.

suki1964

southcoastrgi wrote: »

then you need to get this sorted ASAP as there is clearly a prob with the fire before someone dies, opening a window is not the answer

What would you say is wrong? Because the chimney sweep can't find any thing wrong.

All that is wrong is on some days the industrial extractors are drawing more air then the chimney. Giving them another air source solves the problem. It's an extremely old building and come the winter the kitchens are barely above freezing so we tend to block up as many gaps we can.

grahamc2003

southcoastrgi wrote: »

then you need to get this sorted ASAP as there is clearly a prob with the fire before someone dies, opening a window is not the answer

The syptoms don't point to that at all.


If you turn an extractor fan on, thenthe pressure in the hoiuse will tend to be lowered, and air will enter anywhere it can, manily from the points of least resistance. If the house is really well sealed and the chimney is the only way in, then obviously air will come in that way to replace the air being extracted by the fans.

Won't happen in my old house, even though I've been round trying to block any sources of draughts. The op obvioulsy needs a vent somewhere, probably in the room where the extractor fan is, and that would stop the air entering through the chimney. I'd also have a vent in the room where the stove is, probably near the stove to avoid draughts. The stove is probably currently getting its air from the extractor area (when it's not working), and it would offer less resistance (and therefore a better draw) with a local source of air.