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Bathroom extractor fan


chocccie
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My new bathroom has no windows, so I'm going to install an extractor fan (through the wall to outdoors type).

I went to Brico Marche to yet one and was a bit bewildered by the quantity on offer!  What I want is one that comes on when the light is switched on and goes off a minute or two after the light is switched off.

Could anybody tell me what I need to look out for please?  Do they come in  complete packs ready to be connected to the light on/off, or do I need to buy two separate components?

Thanks  [:D]

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Yes you are exactly on the right lines.  Look for an extractor that says 'Timer' or similar on it.  These can be adjusted to turn off from a few seconds to +/- 10 mins after the light goes off also usually a manual override too.  Dead easy to fit.  I have this one from good old Screwfix

http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A334859&ts=00433&id=15927

but there are lots of others at higher prices - some incorporate condensation controls etc.

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When

I lived in the UK I installed an expensive bathroom extractor that

had a humidity sensor. Well known brand, not cheap, etc. Trouble

was that there was nbo adjustment on the sensitivity of the humidity

detector thing (no idea if any do have that) - so when it rained

outside, fog, mist., etc. the fan turned itself on and had no useful

effect. Waste of money and I ended-up having to install a additional

switch so I could turn the thing off.

Ian

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If your fan is a VMC then yes it should be running on the slow speed all the time, there is usually a switch to boost it to the fast speed.

Likewise with the VMC hydroreglable but these also switch to the 2nd speed when humidity exceeds a preset level as described above. Luckily this is adjustable but they do tend to switch when the outside humidity rises as Ian said, however I consider this to be doing its job as the humidity level inside must have risen also, unfortunately it is just dragging in more wet air as it expels the existing.

I created an appartment in the UK from some timber framed outbuildings (read sheds!) which always was running with damp when I returned, during the refurbishment I fitted a VMC hydroreglable et voila no more problems.

I am a big fan now. Pun unintentional.

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Our VMC was noisey so I removed the link at the back of the switch and now it's just an on/off switch. Suits us.

The VMC is a fan unit that sits in the loft and should pull the air from the kitchen, bathroom and loo and chuck it outside. As has been said it runs all the time, it's only about a 40 watt motor so no real problems. When I had a look at ours there was no hose from the fan unit to outside!!! So all the damp air from the bathroom was just being pumped into the loft space which is pretty well sealed.. Novel!? It now goes outside.

If you can do it then it's a better idea to fit one of these units instead of just a fan through the wall. Almost all of the sheds sell them. Just look for the picture on the outside of the box of a plastic box with 3,4 or 5 4 inch holes in the sides and a cable going into it. They can be as small as about a foot or so cube...

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If only 40w is needed then I'll try and resurrect the idea I put forward a while ago. For those of us with holiday homes prone to the odd bit of damp but having no electricity on when away for long periods - why not solar powered VMC with a back-up lead acid battery?

It would be nice to be running all the time, but if it was not sunny enough and the battery went flat there would be no crisis as it would all start whirring away again when the sun came out.

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Its really not a good idea to control the VMC with an on/off switch. they run so slowly that for them to be effective they need to run all the time.

They should be virtually silent in operation, if they are audible the best idea is to replace the fan box.

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The noise we hear is the air actually entering the 'hole' in the ceiling and where we live is QUIET big time. We hear it all through the night because we sleep with our bedroom door open and the bathroom & loo are almost opposite. So if the link were not removed it was switched off at the breaker. Easier to just flick a switch in the loo than to go into the garage to flick a breaker...

Yes I was a lekkie in a former life, before retirement. Aircarft and computers, mainframes, not these cornered rat PCs!

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[quote user="Monika"]We have a Bathroom extractor fan which is on all the time when switched on at the fusebox. Our PM said that this is normal. I would appreciate any advice and I hope that I did not hijack this thread with my question.[/quote]

In view of Kate Moss mistaking  David Cameron for a drainage engineer did you actually get Gordon Brown to have a look at your bathroom ? ( Sorry could not resist it) But what is a PM ?

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If you have a VMC system in your house, particulary if it is a relativeley new build and you have gas appliances you should not disconnect or tamper with the VMC

On new builds the VMC provides, in conjunction with fresh air inlets, for the extract of any fumes etc that may result if your gas appliance is faulty

If your VMC serves this function then you will be breaking the law and putting your self at risk

A properly installed VMC system will extract air from Kitchens and Bathrooms with the fresh air make up entering the house via grilles ( often over windows ) with the grilles being located in living and bed rooms, thus providing ventilation to through the property to the extract points in kitchen and bathroom

Le Plombier

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I've just discovered an additional benefit of the VMC.

Because it produces a slight pressure drop in the cold and damp areas in which the outlets are positioned i.e toilets/utility room/Bathroom, the heat from the wood burner is encouraged into those areas without the need for an additional distribution system. The actual heat loss is relatively minor and the additional comfort while reading the paper etc is well worth it.

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Perhaps the noisy VMC's are running on the fast speed all the time? I have converted some outbuildings (read sheds) for me to stay in when in the UK, the bedroom is caravan small i.e. double bed and walking space around, I have a VMC outlet in the side wall at the side of the bed and the noise is barely audible, a bit more so on the high speed but still bearable and it is also only 1 meter from the fan casing although well insulated.

I am certain that my unit only consumes 13 watts when on the low setting which it is most of the time, I have however thrown away the leaflet, the electricity consumption while I am not there could suggest otherwise but maybe I have left the TV on standby or some other appliance is using some current.

Can anyone confirm the power consumption?

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[quote user="J.R."]

Perhaps the noisy VMC's are running on the fast speed all the time? I have converted some outbuildings (read sheds) for me to stay in when in the UK, the bedroom is caravan small i.e. double bed and walking space around, I have a VMC outlet in the side wall at the side of the bed and the noise is barely audible, a bit more so on the high speed but still bearable and it is also only 1 meter from the fan casing although well insulated.

I am certain that my unit only consumes 13 watts when on the low setting which it is most of the time, I have however thrown away the leaflet, the electricity consumption while I am not there could suggest otherwise but maybe I have left the TV on standby or some other appliance is using some current.

Can anyone confirm the power consumption?

[/quote]

I have a new one sitting in its box in the barn..... just looked at the details on the box and it says  'consumption moyenne 33w' . This is a bog-standard simple one with neither bells nor whistles.

Probably not what you wished to hear !

p

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[quote user="J.R."]I am certain that my unit only consumes 13 watts when on the low setting which it is most of the time, I have however thrown away the leaflet, the electricity consumption while I am not there could suggest otherwise but maybe I have left the TV on standby or some other appliance is using some current.

Can anyone confirm the power consumption?[/quote]

We bought a "VMC simple flux hygrovariée" yesterday and its leaflets quotes 17 watts  on slow speed, 85 watts on high speed, average 25 watts based on 2 hours a day at hight speed.

It also says "Un système VMC doit fonctionner 24h/24"

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Thank you both.

I think that I did remember right with the 13 watts for the slow speed. Mine is hydroreglable but if I set it to trip when boiling, say rice then it is on fast all the time that there might possibly be a cloud in the sky somewhere!

I actually have the same one in both countries and have finally regulated them both to where I want them, interestingly they rarely trip when cooking and in one property the hob has a window behind it, no extractor yet never steams up with the VMC on low setting. This property is a shed by any other name and before had a huge damp problem but nothing now, the VMC can be on for several hours on wet days but I feel it is a small price to pay.

The property here in France has a roof of uninsulated bac acier over the kitchen and bathroom, during construction it was often running with condensation which would have found its way onto the plasterboard ceiling and walls after soaking the insulation. To guard against this I did 2 things, I sprayed the inside with car body schutz, the texture retarding the moisture from running, and I have left 2 VMC ducts ventilating the roofspace.

This will be my second winter without I hope a damp problem, I can often hear the VMC running on high speed after a cold night following a humid day which before would before have soaked the underside of the bac acier.

I am a total convert to VMC's.

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VMC systems are also useful to rescue kittens,  although I can't quite see how.  We had an emergency call from our French neighbour that one of our workmen had locked one of his kittens into our house (4 days). When he could not find the hidden key and he heard some noise in the roof, he climbed up and saw a little face in the small, covered terracota ventilation chimney. He freed her taking off the cover. However, how this cat  got into the VMC ventilation pipe we will not know until we get out there! 
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  • 4 months later...
I wonder if anybody could tell me what the extractor unit looks like in the roof. I have only looked at it since the "kitten rescue" and I think a hose is missing,  there is nothing to connect the unit to the small ventilation chimney on the roof , or is the unit not supposed to be connected to it, if not does the insulation and roofspace not get damp ?
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[quote user="Tandem_Pilot"]Info here http://www.ideesmaison.com/La-VMC-ventilation-mecanique.html

[/quote]

Thanks for that, that's a very useful site. It looks like there is a piece missing on our Ventilation Unit! I wonder where I can get it?

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