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Bathroom-type 4" Extractors - good ones......

steveinspain

pfm Member
I'm hoping that someone wise like @martin clark may be able to help, although there may be plenty of others who can too..

A client has a 4" extractor mounted right at the top of the stairwell of his 4 storey house to attempt to extract some of the hot air that rises all the way up from the ground floor and it is usually left to run 24/7 during the summer.
A couple of years after they moved in it died, so they had another one fitted which lasted a year - no surprise to me as they were both standard cheapies build to run for maybe 20 minutes at a time, not 4 months. They have now asked me to look into another replacement.
So, I'd like to know if there are any drop-in replacements built for this sort of use that I can suggest to them - it doesn't need to be massively powerful, just likely to last rather more than a couple of years and ideally not too noisy (noisy enough to be audible enough to show it is working as in my head it ever did was hint at moving some air)

This is the sort of thing they currently have for those that like to look at pictures of cheap extractor fans..

https://www.screwfix.com/p/xpelair-...Glc2E5wC4bgfi7xGBMIaAuFAEALw_wcB&gclsrc=aw.ds

Access to outside would require a fairly major scaffold so it needs to be easy to retro-fit from inside, and obviously it doesn't need a humidity sensor or timer. Thanks for any help!
 
I don't know enough about more-robust small 240VAC vent fans, but have an observation - is there anywhere at low / ground floor level that a new fan could be fitted, to supply air into the stair well? Even via a cupboard on the stairwell, on an outside wall/ small undercut on the cupboard door..?

It generally works better to push air through equipment (and buildings!) i.e. for positive ventilation to be blown-in - rather than to try to lower the pressure and hope the air moves where you imagine you want it to (it doesn't so much.) Then -
  • the low level fan could be a useful standard size and quiet, like 6 - 8", which likely offers a broad range of supply.
  • and would be very easy to get to/clean a filter on/inspect/replace.
  • the top of the stair vent can be left as-is as a bit of useful permanent vent.
Just a thought.
 
Does the fan motor have to mounted straight on the wall? I find them noisy and prefer a remote motor in a void but that might not be possible in this scenario? I had umpteen xpelair window mounted bathroom fans burn out on me but a Manrose remote void mounted fan worked faultlessly for many years
 
I have run numerous 4 & 6 inches fans as extracts over the years running for months at a time, continuously.

DO NOT buy an extract fan as sold for kitchens and bathrooms.

Buy an equipment cooling fan - they are essentially indestructable.
 
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I don't know enough about more-robust small 240VAC vent fans, but have an observation - is there anywhere at low / ground floor level that a new fan could be fitted, to supply air into the stair well? Even via a cupboard on the stairwell, on an outside wall/ small undercut on the cupboard door..?

It generally works better to push air through equipment (and buildings!) i.e. for positive ventilation to be blown-in - rather than to try to lower the pressure and hope the air moves where you imagine you want it to (it doesn't so much.) Then -
  • the low level fan could be a useful standard size and quiet, like 6 - 8", which likely offers a broad range of supply.
  • and would be very easy to get to/clean a filter on/inspect/replace.
  • the top of the stair vent can be left as-is as a bit of useful permanent vent.
Just a thought.
And a very good helpful one, thanks. Although to be honest I have never thought the existing fan does makes any serious amount of difference as they always have so many windows open but it's something my client fusses about..

I have run numerous 4 & 6 inches fans as extracts over the years running for months at a time, continuously.

DO NOT buy an extract fan as sold for kitchens and bathrooms.

Buy an equipment cooling fan - they are essentially indestructable.
OK, this sounds like the kind of thing - I'll have a look but if you can point me towards the kind of thing I'd be very grateful. The only type I've seen so far are like computer case fans, and I'd like something more like a bathroom fan in appearance, ie white plastic casing with a grill..
Thank you all for your help and replies.

Edit - having had a quick search I may be able to bodge up something in an old bathroom fan case using something like this -
https://www.amazon.co.uk/dp/B08X6CZP93/?tag=pinkfishmedia-21 so will head off to the garage to see what I've got by way of donor cases before ordering anything....
 
This site contains affiliate links for which pink fish media may be compensated.
Edit - having had a quick search I may be able to bodge up something in an old bathroom fan case using something like this -
https://www.amazon.co.uk/dp/B08X6CZP93/?tag=pinkfishmedia-21 so will head off to the garage to see what I've got by way of donor cases before ordering anything....

By their nature, equipment coling fans are bare fans - you will have to be inventive. How reliable Chinese fans are, I have no idea - they are probably made in China now, but I have used mostly Papst or one of the large Japanese brands.
So far as I recall, none have ever failed here. Every once in a while, I have stripped them, cleaned and re-lubed. They are very simple to dismantle - the set-screws holding the fan assembly to the rotor are usually hidden by the label, remove those and then the rotor is usually held on the shafy by a circlip. remove the clip, job done. The bearing is usually a sintered bronze bush (aka oilite) - soak in meths or paraffin for a few hours, rinse a couple of times, dry, then sit in oil for a few hours, with one bit of the bush above the oil surface. I don't know enough about oils to know any different so usually use something like car engine oil.
 
This site contains affiliate links for which pink fish media may be compensated.
By their nature, equipment coling fans are bare fans - you will have to be inventive. How reliable Chinese fans are, I have no idea - they are probably made in China now, but I have used mostly Papst or one of the large Japanese brands.
So far as I recall, none have ever failed here. Every once in a while, I have stripped them, cleaned and re-lubed. They are very simple to dismantle - the set-screws holding the fan assembly to the rotor are usually hidden by the label, remove those and then the rotor is usually held on the shafy by a circlip. remove the clip, job done. The bearing is usually a sintered bronze bush (aka oilite) - soak in meths or paraffin for a few hours, rinse a couple of times, dry, then sit in oil for a few hours, with one bit of the bush above the oil surface. I don't know enough about oils to know any different so usually use something like car engine oil.
Thanks again for taking the time to help. I've now ordered a bare fan that I can cut down the casing of so it'll fit into the duct part of a bathroom fan after removing the existing mechanism.
I'm sure I'll have a happy client!
 


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