mains time delay switch

What you want is a fan with an overrun timer built in. They are quite cheap and readily available. If the switch is to be in the bathroom just use a pull-cord like the light switch.

depending on what the OP wants to remove if its smells then go for a timed fan, if its condensation the you can get fans what will only come when the condensation reaches a set level

I already have the over run timer version but was told you have to switch it off first (pull cord or switch) for the timer to take over otherwise the fan just stays on.

================= You're correct in believing that the timed fans have to be switched off. They usually run indefinitely unless you remember to switch off. The timer only takes over once you've manually switched off.

Is this the thing you're looking for - it switches off automatically when it 'times out' and it appears to fit a standard switch box. Or perhaps this is the one you're trying to avoid!

Only because you are probably using an ordinary switch. If you use a momentary switch in effect it turns on-off with one press/pull.

Owain

MK (and probably others) do a DIN rail mounting timer, intended for staircase lighting, using a momentary switch.

The easiest way would be to use a fan with an inbuilt timer (which it sounds like you already have) and use a *momentary* switch (available in plateswitch or pullcord style from MK) to link Live and Timer terminals on the fan.

Plateswitch

You'd need a different switch to run the light, if this matters.

Owain

I misunderstood your question. You could use a momentary switch so the fan only runs for the timer period

================= I doubt if these switches will do what you asked about in your original post. Unless I misunderstood your question your problem was remembering to use the on / off switch before allowing the fan timer to operate. The pull cord version ( which I have in my bathroom) has to be pulled once to switch on and then a second pull is required to switch off. Although the action is different from a normal light switch (pull / pull as opposed to press / press) you still have to *remember* to switch it off.

As I understood your question you want a switch which can be switched on manually and which will then switch itself off automatically after a timed interval if you forget to switch it off - rather like a clockwork kitchen timer. The pneumatic switch I suggested might be your only answer unless somebody can suggest an electrical version of this type of automatic off switch.

Cic.

The switch you suggested is spot on and it will be fine. I can live with another seperate switch for the lights. Really appreciate your advice Thanks again

You can probably do an ordinary switch and a momentary switch mounted together in one faceplate if you use MK Gridswitch. Probably special order from an electrical wholesaler.

Remember your fan will still need a triple pole fan isolator as well

Owain