fan transformer

[Benjamiin]

Morning all, got a vent axia 12v fan in my bathroom, wiring is standard procedure, 3core from light to isolator, 3 core from isolator to transformer and a twin from transformer to fan.
The install was done by a firm about a year before I moved in and they've done a good job to be fair, the only issue is that ive replaced the transformer once and its rattling again, sounding like its giving up!!
The transformer is outside the bathroom so no ingress of water issues, however its installed on the ceiling, so im wondering if anyone has had issues with this? Does a transformer prefer to be wall mounted or am I off the mark? Cheers

 

[Deleted member 26818]

Transformers don't in the main care how they are orientated.
It could be that you are just unlucky.
It could be that the transformer is overheating due to being covered by insulation, or because there is no air circulation.
It could be that the transformer is under sized.
It could be that the the extract is badly positioned, and wind is causing back pressure causing the fan to work harder which in turn is overloading the transformer.
Or it could be a bad transformer.

 

[Benjamiin]

Thanks spinlondon, transformer is definitely right for the fan, and now you mention it the backdraft can be pretty strong, thanks for your help mate

 

[Marvo]

....the only issue is that ive replaced the transformer once and its rattling again, sounding like its giving up!!

When you say the transformer is 'rattling' is it a buzzing of humming type noise or a mechanical rattle? Is the transformer an electronic type or wire wound? Are you sure it's not the actual fan itself that's rattling?

 

[Benjamiin]

No marvo its definitely the transformer, the fan is 4 metres away and inside the bathroom, and its definitely a mechanical rattle, it does buzz a bit, but no more than any other transformer,! Thanks for your help

 

[Marvo]

Hmmm, I've got no idea what would cause a small transformer to 'rattle', as already stated you can generally mount transformers in any orientation as long as it doesn't reduce the air flow around them.

When you say yours is on the ceiling is it covered in insulating material?

What's the VA rating of the transformer?

Does it have a built in rectifier or the the fan supplied with 12V AC?

If it's AC output you might be able to replace it with a SELV wire wound (inductive) lighting transformer which are pretty cheap to purchase. It might be worth oversizing any new transformer by 30%.