Looking for help with bathroom extractor fan

Discussion in 'Electricians' Talk' started by JayKay70, Nov 4, 2018.

  1. JayKay70

    JayKay70 New Member


    I am looking to replace my old extractor fan and am confused on what one i can get....

    Bathroom fan with timer?
    Bathroom fan with timer and humidistat?
    Bathroom fan with pull cord?
    Bathroom fan with PIR?

    This is the fan i have: https://www.envirovent.com/product-downloads/filterless_extract_fan_230V_V7_LR.pdf

    Coming through the wall behind the extractor i have 3 wires, Red - Black - Earth (not being used) going into a block and then from the block two wires Red and Black going into the extractor fan.

    The wire in the wall goes to this box on the other side of the bathroom:


    The light switch has no effect on the extractor, it still works wether the light is on or off, it seems to spin all the time but when i pull the pull cord on the extractor it boosts the spin.

    One very confused person on what type of extractor i can buy to replace the one i have got without messing around with a new wiring system.

    Any ideas would be most welcome.

    All the best


    Attached Files:

    • 1.jpg
      File size:
      185.8 KB
    • 2.jpg
      File size:
      189.6 KB
  2. Flame

    Flame Member

    do you still want one that's permenantly on? could you not replace like for like if you have no issue with it?

    You could go PIR which would act as your switch & only come on for X time when it sense's you.
    Last edited: Nov 4, 2018
    JayKay70 likes this.
  3. JayKay70

    JayKay70 New Member

    Hi Flame,

    I don't mind if it is permenantly on, i don't think i can have one with a timer as i think they need to be connected to a light switch.

    I don't want to change it for a like to like as it's a beast, the thing is a eye sore, i was looking for a more slimline one.

    I was looking at the PIR ones but they seem to be very expensive when looking for a slimline one, the ones i am looking for look wise is something like this: https://www.screwfix.com/p/vent-axi...oom-extractor-fan-with-timer-white-240v/6468h

    Judging by how mine is wired maybe i am narrowed down to a PIR one or one with a cord?

    Also that box in picture one, the one on the left is two wires with a fuse, one coming from the right hand box, the other going too the fan.....the box to the right has a wire coming from the ceiling and the other wire going to the box on the left, the only difference is this box has some kinda circuit board.

    All the best

  4. Allsorts

    Allsorts Well-Known Member

    Ah! That 'Envirovent' unit might be a transformer as the instructions below it suggest it's a 12V system, so very safe.

    I suspect that the mains supply comes down to that isolating switch and hence to the 'envirovent' box where it's reduced down to 12V and then on to the fan itself.

    Since the fan itself has the on/off switch, that'll be a 'permanent' 12V supply going to it, so in theory you could fit a timed or humidistat or PIR type replacement, provided they exist.

    The way you fan is currently always spinning, I wonder if this is down to draught air being vented through and causing the fan to spin?

    As to choice of fan type, PIR means it'll always come on whenever you pop in for a wee - do you want that? Humidistat type is handy to control humidity, but you'd be always switching it on manually anyway, so is this needed? A timed type will keep on running after you've left the room and odour behind, so that's a good thing, yes?

    First you'd need to confirm it's a 12V system, and then search for your 12V options.
    JayKay70 likes this.
  5. JayKay70

    JayKay70 New Member

    Hi Allsorts, thanks for the detailed reply.

    It's deffo not a draught, it's deffo a 12v system, phoned a shop that deals with only extractor fans and they said the only one you can have would be the SELV continuous Ventilation Unit which cost around £100+ marko_O

    Bit confused as to why i have to have a continuous fan running all the time, i would of thought i could just fit a 12v fan with a pull cord that i pull when i want the fan on?

    I did find a 12v fan with pull cord: Xpelair LV100PS Low Volt Bathroom Fan Pullcord Square but not 100% sure this will be ok? or there is this one, bit expensive though: https://www.screwfix.com/p/xpelair-lv100ts-8-4w-bathroom-extractor-fan-with-timer-white-12v/7816h

    EDIT: Don't think the linked one above from screwfix will work as it looks like it needs to be also connected to a switch.


    All the best

    Last edited: Nov 5, 2018
  6. Flame

    Flame Member

    I think it's going to be a case of google google google til you find what you're looking for, a slimline/lower profile 12V fan with built-in pull cord, that seems to be your preference?
    JayKay70 likes this.
  7. Allsorts

    Allsorts Well-Known Member

    Hi Jay.

    I have very limited knowledge of this type of system. If it's always running at a lower speed, then that suggests that the pull cord activates a switch which by-passes a resistor inside the fan housing. Ie - the fan receives a constant 12V from the transformer, but this is fed via a resistor or similar inside the fan housing so the fan runs at, say, half speed. If you pull the cord to switch it 'on', what this likely does is to by-pass that resistor so the fan receives the whole 12V. That's a guess. I've never personally heard of a fan that is always running at a low speed - seems nuts to me.

    So, in theory, if that fan unit is receiving a constant 12V supply, then pretty much any 12V fan can be fitted. The new fan's pull cord would then act to simply turn the fan on and off like a 'normal' fan.

    However, why consider a different extractor model which costs around £70 - and which comes with its own transformer (which one will you use?!) when you can buy an Envirovent for a similar price? Surely a straight swap makes sense?
    JayKay70 likes this.
  8. JayKay70

    JayKay70 New Member

    Hi all,

    Thanks for all the info, think i am gonna go down the wiring route and completly change it all, this way i have more options what i can buy.

    Gonna get rid of the old fan and the 3amp Isolator+Transformer

    Gonna buy a IPX5 rated fan with timer and fit a Isolator switch in the loft just above the fan and then from the Isolator switch too the light switch.

    Gonna buy some Prysmian 6243YH 3-Core & Earth Cable 1mm² x 10m Grey : https://www.screwfix.com/p/prysmian-6243yh-3-core-earth-cable-1mm-x-10m-grey/43415

    Will the above cable work from fan too isolator switch too light switch or do i have to have a different type of cable coming from isolator switch to light switch?

    Sorry to be a pain, but does the above sound right?



Share This Page