Help with extractor wiring please

[JohnB]

Hi

My toilet extractor fan has stopped working - it is a Wickes one with timer and was fitted when we had the bathroom done 18 months ago - I am OK with straight replacement electrics but not the problem tracing element ! So I want to figure out whether the unit has gone or whether there is a problem in the switch or circuit.

I have taken the cover off the unit to test the circuit. There are 3 contacts on the terminal block feeding the extractor - a red one a blue one and a brown one. If I switch the light on (also normally controls the fan) there is power on the red and blue cicuit but not the red and brown circuit.

There are 2 power cable supplies coming into the unit - from them there is one red supply to the red terminal, one black one to the blue terminal, and one red and one black supplying the brown terminal.

So is the lack of power between the red and brown terminals normal ? Do these symptoms indicate that the unit is faulty and needs replacing - which I can do. Or would you think there may be a problem at the light switch (wire popped out perhaps) ?

I havent looked in the switch because one of the screws seems to be cross threaded and I can't get it out easily - i'm sure if I force it i'll snap the back box connector and need to replace that - so would rather not do that unless I know I have to.

Thanks for any tips.

-- JohnB

[JohnB]

Ooops sorry my eyes are not what they used to be !

The Brown terninal only has the one (red) wire coming in from the supply and there is power between it and the neutral.

So looks like it is the unit

-- JohnB

[Doctor D]

A timer fan has two feeds - 1) switched live to trigger the fan 2) permanent live to keep the motor running on the timer after the light has been switched off. It also usually has a common neutral.

Check that one live is always live, and that the other is live only with the switch on. Check the neutral path. If these are all okay replace the fan unit. They're £9.59 in Screwfix.com (if their website is actually working) product number 15927. If you're worried about upsetting Jerry (see earlier thread about Screwfix False Promises) you can buy them in B&Q for about £25, or at your local hardware shop for even more probably! You could buy another Wickes one for compatibility, but 18 months is a bit short for a fan life and you may want to try another make.

The usual place to pick up both live feeds and neutral is at the light in the room where the fan is located. If the fan is okay and you have a supply problem and can't get into the isolator switch, try looking here first, then you may have to break into the isolator switch.

[JohnB]

Cheers Doc. I think it is the unit now so will check out Screwfix.

-- JohnB