Help please 2x fan nightmare!!

[JDLDIY]

Hi there, yes I know it's yet another fan question, sorry - I have searched before on this but I'm still confused.

So, had place partly rewired by electrician, we have problems with fans in 2 bathrooms. Ideally I wanted the fans to come on with the lights and then when the lights go off run on their timers then switch themselves off.

One of the fans seems to come on when it wants, sometimes when the loft lights are turned on, then it will run sometimes for ages without cutting out. The other fan (which the electrician installed) sort of worked ok but when isolated somehow it would dimly illuminate the low voltage downlights in the bathroom.

The one the electrician has done from start to finish (forget what they're called - bit in middle opens like a camera lens) he's wired now from it's own switch so you have to turn it on outside the room if you want it on, the other one still does what it wants.

The circuit they're on has lowvoltage downlights in some rooms, tungstens and fluorescents in the loft.

Please help, I can put up with the one he's done although its not ideal but the other one drives me mad.

Cheers.

 

[rebuke]

I'd say get your electrician back and get him to sort it - wiring up fans is not a difficult job, they just need a permanent live, switched live, neutral and earth - take them from the right point and it should be absolutely fine.

The fan that randomly turns on when it wants could be knackered - the switching is controlled by electronics which can fail, so it might be worth replacing that. It should be trivial to wire the brand new one correctly though, the fault you describe sounds very odd, it could just be a capacitive effect, but seems unlikely...

 

[electronicsuk]

If your electrician hasn't carried out the work you want (which, from the sounds of it, is perfectly feasible) then either he doesn't understand how to do it, he isn't listening, or it would cause him too much inconvenience and he can't be bothered. I'm not sure I would want him back in my house.

 

[JDLDIY]

Hi rebuke, thanks for your reply. This has already caused much scratching of heads, the electrician just can't come up with anything better. I've looked at how he's wired it and it's how I would have done it.

 

[flameport]

Is there a dimmer involved in this mess somewhere? Perhaps in one of the other rooms supplied by the lighting circuit?

Another possibility is that the switched live to the fan(s) is actually a neutral from one of the other lamps, so the voltage on it depends on what other lights are on/off at the time.

 

[tombox68]

hi i would go with flameport with

Another possibility is that the switched live to the fan(s) is actually a neutral from one of the other lamps, so the voltage on it depends on what other lights are on/off at the time.

as it does sound like you are getting a back feed of something for the fan to come on.you could dissconect the s/w feed in fan and see if it comes on ??it shouldn't .and work back from there

 

[Taylortwocities]

You may get random triggering if the wiring has been done without an earth. You may then get induced voltages in teh feed wire to teh fan causing it to come on at random times.

Sounds like you need a sparky with some nouse. Per the above, this isnt rocket science..

 

[ColJack]

no-one considered that they might be fans with humidistats? or built in PIR's?

these the fans? http://www.tlc-direct.co.uk/Main_Index/Ventilation_Index/4_Inch_Fans/index.html#Airflow_Icon_Fans

 

[Taylortwocities]

no-one considered that they might be fans with humidistats? or built in PIR's?

If you're so clever, why aren't you rich ??

 

[JDLDIY]

Many thanks for the replies. The fan the sparky wired in is a icon low voltage with a timer module, no PIR/humidistat. He originally wired it to come on with low voltage bathroom downlights and through an isolator switch. It sort of worked ok but when isolated all the ceiling lights came on dimly! So he felt that wasn't right and now I have 2 gang switch by door, one for lights, one for fan, which then runs thru fan isolator switch and fcu.

We rang icon who said they knew about this happening but didn't offer a solution.

The other fan I installed ages ago and never worked ok, leccy rewired it during rewire so could just be fubar.

LV downlights + fans must be common along with wanting them to come on together so I thought I'd ask here.

Thanks again.