whirring noise

[Mel]

We have a unicorn S3 Valencia bought new in 2015. It has a rear washroom. The big box of electric fuses (is it called a pcb?) is located below the tall fridge. When we switch on the washroom light the box immediatly starts whirring as if a fan in it has come on: switch off the bathroom light and the whirring switches off. No other light or appliance causes this. For all I know it has always done it and I have never noticed before but I think that is unlikely.
Should I be worried? Is this normal? I don't think the use of the light is causing the box to overheat as the whirring switches on with switching on the light and switches off with switching off the light, so not really allowing any time for heat to build up or dissipate.
Thanks in advance for any help
mel

 

[WoodlandsCamper]

Hope it's nothing too serious and you get it sorted out before the Fest.

 

[Dustydog]

No idea Mel. Sorry.
why not ring Di Moody at Bailey. She may be able to give you a steer .
See you soon. BTW as far as I know there is no fan in the fridge or consumer unit.

 

[Mel]

Thanks guys. It is definitely not the fridge and is clearly activated by the washroom light. When I say whirring, it is more like a whirring/high pitched humming. I will have a look if the washroom light is on a different fuse to everything else. There seems to be clear writing on the fuses in the box. Just a question of finding my glasses and lying on the floor. The handbook is not helpful (in most respects).
mel

 

[Woodentop]

Bailey's use a 20A switched mode power supply that is inside the power box and it has a fan inside the case. Likely it is running close to its temperature limit in a closed unventilated space, so when you switch the light on (I assume halogen?) the additional current drawn is enough to make the sensing decide it needs to do a bit of cooling so switches the fan on and hence the noise.

At least your fan works - many don't and you end up with a boiled and very smelly power supply. Been there, don't that, got the T-shirt.

 

[Montrose]

Hi Mel,
Its nothing to worry about, it is a small fan in the PCB unit
BUT, Bailey fit halogens (2 x 10 amp) in the washroom light unit.
Get rid and replace those bulbs with LED's ( 2 x 1.2 amp)
(same two prong fitting) so just pull out and push in the LED's - and Voila !
you won't hear that fan again when visiting the loo !

 

[Woodentop]

Hi Mel,
Its nothing to worry about, it is a small fan in the PCB unit
BUT, Bailey fit halogens (2 x 10 amp) in the washroom light unit.
Get rid and replace those bulbs with LED's ( 2 x 1.2 amp)
(same two prong fitting) so just pull out and push in the LED's - and Voila !
you won't hear that fan again when visiting the loo !

Erm, that should be watts, not amps. 10A @ 12V is 120W: put two in and you will set fire to the roof!

The bulbs or LED replacements are G4 - that is 4mm pin spacing.

 

[Mel]

Thank you both. That explains why the washroom light was activating it and no other light was. I have been going around the van turning lights and appliances on systematically to work out what was going on.
mel

 

[Montrose]

Welldone Woodentop
Yes, that was a whoops !! on my part
Indeed its was watts NOT amps,
looks like Mel has found out now and can sort it out now that you have
been good enough to clarify the LED replacement spec.

 

[Woodentop]

Hopefully not too late.

There is another possibility. The fan is whirring because it is (1) having to work too hard, (2) chocked up with fluff and dirt, or (3) on its way out.

The simple solution is to buy two small (2-3") 12V computer fans, wire them in series so they run but at significantly reduced speed, and fit one over the side vents (upper left?) of the power box blowing in and the other over the top vents sucking out. This will cause a small flow of air that is well sufficient to stop the internal fan working but will be quiet enough not to keep you awake. They should be powered through a switch or off the main 12V switched supply.

The direction of rotation and air flow of the fan is embossed on the outside of the fan outer casing.

To add a tail to that, if you get similar 4" fans and fit one behind the lower fridge vent blowing in and the other behind the upper fridge vent blowing out, again wired in series and on the switched 12V supply, the improvement in the fridge efficiency will be such that no matter how hot it gets outside you will still be able to freeze icecubes!

 

[Mel]

Thanks wooden top. I like your simple solution. However, as the van is barely 12m old, it is still under warranty. So an ever simpler solution. I think it is just the bathroom light, as all else is Ok. I will source some LEDs for next time we are away. Thanks again
Mel

 

[Woodentop]

Thanks wooden top. I like your simple solution. However, as the van is barely 12m old, it is still under warranty. So an ever simpler solution. I think it is just the bathroom light, as all else is Ok. I will source some LEDs for next time we are away. Thanks again
Mel

Why bother. If the van us under warranty take it back and get the dealer to fix it. They just nick a power supply out of another van, push it in, and you'll be on your way - silently.

Our Peg has three 2x10W ceiling lights and our PSU fan never runs - and that is a known worker. It's just a poor design issue by Bailey's supplier.