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Need to replace bathroom fan but original hole too large.

Discussion in 'Electrics UK' started by bullethead123, 29 Dec 2020.

  1. bullethead123

    bullethead123

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    Hi all,
    My bathroom extractor fan has developed a fault in that it causes the lights to trip out and needs replacing. It seems to be the original fan (well done for 46yrs service) and the (square) hole wherein it is located measures 190x190cm.
    I can only find replacements measuring around 160x160cm, so is there an adaptor plate on the market which I could use?
    If so it would be great to get a link,
    Chris.
     
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  3. KenGMac

    KenGMac

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    bullethead123, good evening.

    Suggest that with such an old unit any adapter plates may ??? not be available?

    How about you consider making an adapter plate your self, out of [say] Ply or thick plastic sheet?

    Ken.
     
  4. sparkwright

    sparkwright

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    As above is the 'normal' way of over-coming such situations without a lot of fuss.
     
  5. Tigercubrider

    Tigercubrider

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    Line the hole with a 2x1 frame
     
  6. bullethead123

    bullethead123

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    Thanks for the replies. I guess a thick plastic sheet is the way to go
    Where would be the best place to source such a thing?
     
  7. Harry Bloomfield

    Harry Bloomfield

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    An off-cut of white plastic from some soffit.
     
  8. KenGMac

    KenGMac

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  9. 333rocky333

    333rocky333

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    Can you repurpose the front off the old fan

    Thats a bloody big fan, sure its not millimetres
     
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  11. SUNRAY

    SUNRAY

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    The similar thing i had was a big rectangular box about 12x9" with a 110mm spigot. it had been push fitted to the air duct which finished some 70mm inside the brick wall which meant the box was substantially in the wall then filled round with plaster.

    When removed I had a 12" [300mm] high by 9" [225mm] wide hole in the brickwork. When the replacement fan was fitted to the duct the whole of the fan was at best 25mm within the line of the wall, I used 4 pieces of 94x44mm timber [4x2" PAR]
    upload_2020-12-29_23-1-36.png and glued them 44mm into the hole with gripfill using a piece of timber as a depth gauge to get them all flat and even. Once painted to match the room the fan sat in a fairly smart recess in the wall.

    Which ever way it's done there will be an outline of somesort unless some decent plastering is done.

    So what I'm saying is I agree with Tigercubrider for minimal impact.
     

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  12. SUNRAY

    SUNRAY

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    upload_2020-12-29_23-44-53.png
     
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  13. bullethead123

    bullethead123

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    Thanks for your input Rocky. The fan aperture is 19x19cm though the fan, which sits well within the aperture, is smaller.
    Thanks for the detailed drawings Sunray, I think what I will do is, as you and Tigercubrider suggest, line the aperture with 2x1 or inch battening but also use a bright white chopping board, cut to size with a round hole (to seat the new fan in) to cover the aperture fully.
    I guess I should also try to remove the old fan to maximise the extraction airflow.

    Thanks to everyone who has responded,
    Chris.
     
  14. SUNRAY

    SUNRAY

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    If you're covering the whole thing, do you need to fit the wood battens?
     
  15. 333rocky333

    333rocky333

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    Fans that size sometimes tend to be Centrifugal fans, they are more powerfull, than Axial fans which are a lot cheaper.
    is there some sort of ducting attached, you may need some power to drive the air through it
    Photos may help of the old fan label, ideally you should try to match the Air movement of the old unit or you could just be wasting your time.
    If you do want an Axial fan unducted, check for 6 inch fans rather than 4 inch, they will likely cover the hole
     
    Last edited: 30 Dec 2020
  16. SUNRAY

    SUNRAY

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    That was the case with the big box i described but the manufacturer was able to recommend a 4" fan which had about 90% of the airflow power. The axial fan was suprisingly high current, something like 40W IIRC. I remenber thinking it's more than twice the power of the LED. Oh and noisy but not as bad as the centrifugal it replaced.

    I'd assumed this runs into a duct otherwise I'd have made the same suggestion.
     
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  17. Sureitsoff?

    Sureitsoff?

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    expelair do a 6in fan with a 225/9in square fascia if that might cover the hole and mean a simpler install. others will probably do similiar
     
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