Replace old extractor fan - no permenant live - options

Discussion in 'Electrics UK' started by dishman, 7 Jul 2016.

  1. dishman

    dishman

    Joined:
    8 Jul 2008
    Messages:
    1,231
    Thanks Received:
    92
    Location:
    Derbyshire
    Country:
    United Kingdom
    Hello all

    Opened the cover of an old extractor fan as I had a feeling it was full of dust and needed a clean out. I had a suspicion it may not be performing as it should as it has never been cleaned out in its life. Upon opening the unit, it was indeed full of dust.

    It is an old (circa 1970s) nuair centrifugal fan. It is very quiet and seems to perform OK, although I have no airflow figures for it.

    According to my calculations the bathroom should use a fan that moves 77m3/hr. I have no idea if this fan achieves this.

    It is however powered by the light switch only, and whilst hoovering inside I could see it only had three connections, switched live (I assume), neutral, earth.

    Does this mean, without a rewire, I cannot replace it with either a timed and/or humidistat model as I can see no permanent live?

    The bathroom has no window so the fan is quite important. While the bathroom does not suffer from any mould, a timed and/or humidistat model may be an improvement in this situation.

    In the mean time the clean out should have, at least, helped performance.

    As a caveat, I would not be replacing the fan myself, I just wanted to know what is possible based on the current wiring set-up.
     
    Last edited: 7 Jul 2016
  2. Sponsored Links
  3. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    75,073
    Thanks Received:
    4,359
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    "rewire" is a bit of an exaggeration. Most likely it is fed from the lighting circuit, at the ceiling rose of the bathroom. If you can get access, for example in the loft or by lifting floorboards in the room above, it is a trifling job to change the cable.
     
  4. dishman

    dishman

    Joined:
    8 Jul 2008
    Messages:
    1,231
    Thanks Received:
    92
    Location:
    Derbyshire
    Country:
    United Kingdom
    True.....I meant, localised rewire...

    It is a flat. So zero access to roof void.

    Sounds like it should not be too bigger job then if access can be found.

    Thanks
     
  5. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    75,073
    Thanks Received:
    4,359
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    If you are lucky there will be a suspended ceiling with a void above.
     
  6. 333rocky333

    333rocky333

    Joined:
    12 Jan 2008
    Messages:
    8,461
    Thanks Received:
    912
    Location:
    Essex
    Country:
    United Kingdom
    Depending on where the switch line comes from, it may be possible to move that, so the fan just has a permanent supply, then get a fan with built in controls, theres all sorts nowadays, pir motion sensors, etc, even ones you set using an App on your phone
     
  7. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,782
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    Why did whoever installed it not think "I know it's not a timed fan, but I'll use 3-core & earth just in case"?

    WTH is wrong with some people?
     
  8. sparkwright

    sparkwright

    Joined:
    20 Aug 2009
    Messages:
    8,958
    Thanks Received:
    1,128
    Location:
    Dorset
    Country:
    United Kingdom
    You said 1970s.

    Not sure if timer fans and the like with 3 cores and earth were used much.

    Also, if 1970s, does this mean a purpose built flat?

    If so, circular conduit MAY have been used which will make drawing an extra core in a doddle.

    Photos please if you can.
     
  9. dishman

    dishman

    Joined:
    8 Jul 2008
    Messages:
    1,231
    Thanks Received:
    92
    Location:
    Derbyshire
    Country:
    United Kingdom
    Yes it was a purpose build 1970s low rise block. As far as I can see it is standard three core of the period. But here are a few photos for you to double check.

    The fan and housing were full of dust. The fan was worse that that initial picture. That was already after it had been hoovered. It was so full of dust I thought the fan was white initially.

    Cleaned the fan and popped it back in. It runs as good as new and probably shifts a lot more air now. I wonder if I can work out a rough m3/hr based roughly on the fan size.

     
    Last edited: 9 Jul 2016
  10. Sponsored Links
  11. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,782
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    Most of which was dead skin.


    Don't let it get so clogged again.

    If you're married, warn your wife that we have voted to move to Ukipitopia, where she will officially be termed a slut if she doesn't clean that properly.
     
  12. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    37,800
    Thanks Received:
    4,256
    Location:
    Retired to:
    Country:
    Portugal
    What relevance is it, when -

    Work and expense for an improvement on no problem hardly seems worthwhile.
     
  13. dishman

    dishman

    Joined:
    8 Jul 2008
    Messages:
    1,231
    Thanks Received:
    92
    Location:
    Derbyshire
    Country:
    United Kingdom
  14. dishman

    dishman

    Joined:
    8 Jul 2008
    Messages:
    1,231
    Thanks Received:
    92
    Location:
    Derbyshire
    Country:
    United Kingdom
    Thanks for the reply EFLimpudance.

    I would agree with you, however it depends on the occupant. It was just something to consider to mitigate future issues with less discerning tenants.

    Hence, given the age of the fan, the fact I opened it up to clean it, a consideration was made into the worth of replacing it with a more user friendly/technically advanced model.

    Since it seems to work much better now and it is quiet, I do intend to keep as is for now.

    An overrun would be nice though just to help.
     
  15. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    37,800
    Thanks Received:
    4,256
    Location:
    Retired to:
    Country:
    Portugal
    Ah. I did not realise it was to be let.

    You may need more than a fan, then. :(
     
  16. dishman

    dishman

    Joined:
    8 Jul 2008
    Messages:
    1,231
    Thanks Received:
    92
    Location:
    Derbyshire
    Country:
    United Kingdom
    Indeed...

    It has served well thus far....with good tenants.

    The possible saving grace is that the bathroom has no windows, which means the light and therefore the fan have to be on to do anything in there. I think this helps a lot.
     
  17. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,782
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    If there's a fan isolator be assured that some t**t of a tenant will turn it off and leave it so.
     
Loading...

Share This Page