Wiring basic bathroom extractor to timer

[Matthew Robinson]

Hi,

I've got an old bathroom extractor fan that doesn't have a timer on it - it's just attached to a switch on the wall. I'd like to get rid of the switch and wire it up so it will come on when the lights do, then stay on for a few minutes after.

I know I could buy a new fan, but that would mean a lot more work.

I've read about how the timed fans work, with the permanent and switched live - I assume there's a "switch" I can buy to retrofit that functionality to my non-timed extractor.

Really, I just need the name of the part - I don't know how to phrase what I want into something I can put into google, but any advice is welcome.

Thanks.

 

[NozSpark]

There are no direct retrofit timer modules for extractor fans (except for the Icon range) however you could do it with other parts which would cost far more than a replacement fan and any rewiring that would be required.

 

[col]

If there's never been a timer on it, you may not have the 3-core & Earth cable it will need.

How about a humidistat fan instead?

Might be able to change the switch to a fused spur if there isn't one already & if it's in a suitable area.

 

[Doc Hudson]

Easiest solution is to replace the switch with a time lag switch. http://www.toolstation.com/shop/p83921?table=no Other than that I would suggest a new fan as the next easiest option.  

Doc H.

 

[Davethsparky]

There are no direct retrofit timer modules for extractor fans (except for the Icon range) however you could do it with other parts which would cost far more than a replacement fan and any rewiring that would be required.

Yes there are, man rose make a separate timer module which allows timer functionality to be added to any fan, they fit on a single pattress. 

If if you look at the Honeywell sundial wiring plans pack you'll see a diagram where the same unit is used to add a timed pump overrun to a boiler system without an internal overrun facility.

 

[Matthew Robinson]

If there's never been a timer on it, you may not have the 3-core & Earth cable it will need.

How about a humidistat fan instead?

Might be able to change the switch to a fused spur if there isn't one already & if it's in a suitable area.

I've not looked yet, but if it has a 3-core+earth cable, I'll just replace the fan. 

I'm expecting to find 2 core+earth, and in that scenario, I wanted to wire it up like this:

Fan

   |

[MAGIC] --- Permanent Live

   |

Lights ( Switched Live )

Where 'magic' detects the switched-live from the lights, then uses the permanent live input to keep the fan on for a few minutes after the switched-live goes off.

It's the name of the 'magic' part that I'm after. Surely there's something I can buy to do that job ( it's just the same thing that's inside a normal delayed-off fan, but as a separate unit ).

 

[Davethsparky]

 Surely there's something I can buy to do that job

There is a product which does exactly what you want.

are you an electrician?

 

[Matthew Robinson]

There is a product which does exactly what you want.

are you an electrician?

No, I'm not.  What's the product?

 

[Matthew Robinson]

Easiest solution is to replace the switch with a time lag switch. http://www.toolstation.com/shop/p83921?table=no Other than that I would suggest a new fan as the next easiest option.  

Doc H.

Thanks, but I'd prefer it if it was automatic ( without going to the trouble of replacing the wire to the fan, as it's hidden behind the tiles, so I assume I won't be able to replace it easily ).

 

[Davethsparky]

No, I'm not.  What's the product?

The elctrician you employ to do the job will be able to supply it. 

 

[Andy™]

icon fans have a PIR module that would switch it on / off automatically

 

[Doc Hudson]

I've not looked yet, but if it has a 3-core+earth cable, I'll just replace the fan. 

I'm expecting to find 2 core+earth, and in that scenario, I wanted to wire it up like this:

Fan

   |

[MAGIC] --- Permanent Live

   |

Lights ( Switched Live )

Where 'magic' detects the switched-live from the lights, then uses the permanent live input to keep the fan on for a few minutes after the switched-live goes off.

It's the name of the 'magic' part that I'm after. Surely there's something I can buy to do that job ( it's just the same thing that's inside a normal delayed-off fan, but as a separate unit ).

One option for your magic is: https://www.tlc-direct.co.uk/Products/BGDT20.html But does seem expensive when a complete timer fan can be got for £20.  http://www.screwfix.com/p/manrose-xf100t-20w-axial-bathroom-fan/15927

Doc H, 

 

[NozSpark]

Yes there are, man rose make a separate timer module which allows timer functionality to be added to any fan, they fit on a single pattress. 

If if you look at the Honeywell sundial wiring plans pack you'll see a diagram where the same unit is used to add a timed pump overrun to a boiler system without an internal overrun facility.

Ooooh,, so there is.... :coat

Every day is a learning day

 

[Essex1]

There is a product which does exactly what you want.

are you an electrician?

I doubt it mate. It is in the DIY section. 

 

[Davethsparky]

I doubt it mate. It is in the DIY section. 

I hadn't noticed what section it's in, but I had a suspicion he wasn't, hence asking. I don't advise diyers

 

[Matthew Robinson]

One option for your magic is: https://www.tlc-direct.co.uk/Products/BGDT20.html But does seem expensive when a complete timer fan can be got for £20.  http://www.screwfix.com/p/manrose-xf100t-20w-axial-bathroom-fan/15927

Doc H, 

Thanks, that's perfect.

Like I said, I'll see if I've got 3 core+earth, or 2c+e. If I've got 3c+e, I'll get a new fan. If not, It'll be much easier to retrofit the functionality with that product you posted.