Recycling vent

[plustone]

I understand the difference between a hood that recycles and one that vents to the outside, but I would like to know what to do in the following circumstances.

I have an extractor that recycles by drawing air from immediately over the hob and blows it into a false flu that is, in effect, a closed “box”. It seems to me that, having been drawn by the fan through the metal and charcoal filters, the air needs to escape from this enclosed space, but there is no way for it to do so. Is it necessary or advisable to fit a vent into the top of the wooden hood so that the cleaned air can escape from the enclosed “box” back into the kitchen?

 

[ban-all-sheds]

What do the manufacturer's installation instructions say?

 

[plustone]

They are totally silent on this subject. My local supplier and the web sites are also useless. As things stand, this forum is my only hope.

 

[breezer]

perhaps you are not supposed to mount it too close to the ceiling?

if its a sealed box the air can not get out

 

[Nige F]

I understand the difference between a hood that recycles and one that vents to the outside, but I would like to know what to do in the following circumstances.

I have an extractor that recycles by drawing air from immediately over the hob and blows it into a false flu that is, in effect, a closed “box”. It seems to me that, having been drawn by the fan through the metal and charcoal filters, the air needs to escape from this enclosed space, but there is no way for it to do so. Is it necessary or advisable to fit a vent into the top of the wooden hood so that the cleaned air can escape from the enclosed “box” back into the kitchen?

Yes.......otherwise you end up with a box full o` fat deposits

 

[empip]

I have seen the odd extractor with a recirculating option, they tended to use an upper outlet returning the filtered air to the kitchen .. Is there not a blanking plate or similar fitted to the 'box'?

 

[JohnD]

I thought from the description that the hood is intended to blow the filtered air back into the kitchen, and a cabinet trim has been fitted in such a way as to obstruct this flow. If I have understood correctly, then this trim or false front needs to be removed or ventilated to allow flow.



PS judging by the area around other recyclers, the inside of this box would benefit from being lined with some non-absorbent and easily cleaned material, as it will get horrible.

 

[plustone]

Thanks to everyone for being so helpful.

There isn't a blanking piece or anything else that would indicate that there should be a vent, it just seemed totally illogical that there should be no way for the air to escape from the "box" other than back through the fan.

The consensus seems to be that there should be a vent, so I'll fit one.

Thanks once again to everyone.