Extractor Fan Timer...HELP!

[jc88]

Hello!
Im in the middle of an extension to our existing house and have installed 3 Manrose shower extractor fans in each shower room. On first installation, all fans turn on with the bathroom lights and stay on for 5 mins after the light has been switched off...perfect...but...2 have them have stayed fine but one now doesnt go off after five minutes, it runs continuously until you switch it off at the isolator...could someone help me with this? am I doing something wrong? is the timer faulty? please help!

 

[Spark123]

Odds are on the timer has gone in the fan.
Can you verify the supply to the fan is correct, i.e. L N and SL?

 

[TicklyT]

Do you have energy saving lamps in the light fitting?
Some low energy lamps, along with the wiring to the light fitting, allow a small electrical charge to build up in the wiring when they are turned off. That charge may be enough to fool the fan timer into thinking the light is still switched on.

It only happens with low energy lighting. The lower resistance of tungsten filament lamps stops the charge building up in the wiring, so if you are using low energy lighting, try it with an ordinary lamp in the fitting before condemning the timer .

 

[jc88]

thanks for the reply, no its connected up to a regular 60watt bulb. I wish it were as easy as a simple bulb change

 

[jc88]

Yes the connection to the fan is correct as its wired the same as the other two which are still working fine...thanks for the reply

 

[jc88]

As the ceilings are not yet up in the build, the fans are very accessible to work on at the moment so im thinking, maybe uninstall the circuit board from inside the 'faulty' fan and try it in a fan that is cutting out correctly after 5 mins...this way I will eliminate any discrepancies in the connections that I may have missed...does this seem like a good idea, or just a waste of time?

 

[STI]

Wouldnt it be easier just to swap the fan with one from the other bathrom rather than stripping out the boards ?

But if it was working and now it isn't , it doesn't seem likely that its a wiring connection fault

 

[ban-all-sheds]

That sort of thing can invalidate any warranty you have.

Swap the whole fan over. If the fault stays with the fan you'll know it's the fan that's kaput, if the fault stays in the same place you'll know it's the wiring.

 

[jc88]

Ok so I did what you suggested and the fault moved with the fan so I've eliminated the problem to the unit! Hooray! Thing is I thinl I my have found the root cause of the problem...on opening up the fan to take a closer look at the board before disconnecting, there seems to be a black kinda of dusty patch on the reverse of the circuit board...?

 

[ban-all-sheds]

Probably left by the component which failed and stopped the timer from working.

Find the receipts, take the fans back.

 

[Taylortwocities]

As the ceilings are not yet up in the build, the fans are very accessible to work on at the moment

I'm a bit concerned about this bit. Are these in-line fans?

Will you be able to access the fans when the ceilings are up??

 

[jc88]

Hello, yes, sorry I should have been more specific...they are the type of shower extractor fan that is built into a spotlight, the fan unit is in the loft space so yes I will have access to it when the ceilings are up, its just a lot easy now when they are not...thankd for the reply

 

[Taylortwocities]

OK, I've been to a site lst week. Bathroom fan not working - the inline unit was in teh ceiling space and plastered over. Ceiling had to come down to access it

 

[jc88]

Thanks for your help everyone! I've disconnected the whole unit and am going to take it back to screwfix tomorrow as its still under their returns policy! Thank you!