Kitchen Extractor Fan Problem

[David1983]

Hi, I'm after some advice on what could possibly be wrong with the extractor fan in my kitchen. It's a Vent Axia which looks quite old (can't see any model number on it) and it turns itself on and off at random. Sometimes it doesn't even turn on and if it does come on sometimes it's nice and quiet and sometimes it rattles a bit.

It's wired from the consumer unit (fans have their own breaker) to a fused switch above my window. From that switch it's wired to a pull switch on the wall near my cooker which controls the extractor fan on/off. When I had my new kitchen installed I had a cooker hood fitted (Baumatic) which is also wired into the pull switch which controls the extractor fan. Where is the problem likely to be and any ideas how I would go about fixing it? Or even why it's happening would be appreciated!

Thanks, David

 

[jj4091]

If the fan in the cooker hood is not displaying the same problem then it would seem like it is a problem with the extractor fan although I do not understand how it can switch itself on when isolated by the pull switch. Can you give more info about switches on the fan itself & the cooker hood

 

[David1983]

Thanks for your reply, the cooker hood works fine. I shouldn't have said that the extractor fan turns itself on as it doesn't. What it does do is when the fused wall switch is 'on' and the pull cord switch is 'off' the fan sometimes comes on of its own accord. But only when the fused switch is switched on.

There are no switches on the fan itself, it is controlled by a pull switch by my cooker which is wired to the fan in the window. As for the cooker hood it has a off button, three fans speed buttons and a lights button. I have tried every possible combination of these to see if they were what causes the extractor fan to play up but they don't appear to be the cause.

 

[comms]

Dont suppose the fan has a humidistat fitted.
The pull switch will operate the instant on/off function, but if there is a perm line to the fan this will operate the timer or humidistat, so when humidity rises the stat will close the perm line contacts & the fan will turn on whether the pull switch is on or off.

Just an idea.

 

[David1983]

thanks again, how would I find out if the extractor fan had a humidistat? It's been in since bought the house and, from looking at it, would say that it's reasonably old. Ex-council property so I imagine they will have put in a fairly basic fan. If it had a humidistat would I be right in thinking that it shouldn't turn itself off when I'm cooking and the windows are steaming up? Just that's the sort of thing it's doing at the moment, totally randomly!

 

[David1983]

If it's any use the extractor fan is a Vent Axia VA150A. Out of interest, as I've already got an extractor fan and associated wiring fitted, how difficult is it to replace my current fan with a new one?

 

[David1983]

From what I've described, can anyone point me in which direction the fault is likely to be - with the wiring and switching or with the extractor fan itself? Thank you in advance.

 

[breezer]

both or one or the other.

why not dissconnect the fan, remove it and put a lead on it and plug it in and see what it does.

 

[David1983]

I've had a look at the pull cord switch on the wall and it's a Vent Axia Variatronic HP2 (which has a build in Humidistat). According to what I've found on the net the HP2 will automatically control the fan but also has a manual over-ride - the pull cord - to get full speed when required.

The wiring into the switch has the mains in from the fused switch and also mains out to cooker hood in the L and N. On the other side there is the live and neutral out to the extractor fan, L(1) and N(1). There is also a L(S) which currently has nothing in it. Should there be anything there? Can it be wired to remove the humidistat from operation and only use the pullcord?

Finally, what should the humidistat be set to?

Thank you one again.