a strange Slow running Manrose MFT100T

[ianphilip007]

A strange one :- replaced an inline mixed flow timer fan like for like yesterday. When powered on at the 3 pole isolator switch the fan was running at 25% speed and the shower light 12v halogen bulb was lit but very dim (note the pull switch for bathroom lights was off) All other bathroom downlights were off. When bathroom pull switch was turned on Both fan & shower light went off, bathroom downlights worked correctly.

All wiring correct on check. Checked 3 pole isolator loose neutral connection found. Retightened everything working as normal.

trying to work out why this would cause the fan to run slowly/dim downlight any ideas much appreciated.

 

[ianphilip007]

to add the fan isolator switch when turned off stopped the fan & light dead ( before fault correction)

 

[Squid]

Disconnect fan see how it all works and then double check the install.

 

[ianphilip007]

as stated the fan and shower light are now working as normal, after loose neutral connection was found.

 

[Midwest]

I was going to suggest perhaps switch line & neutral were mixed up, before you said you checked all wiring & connections.

 

[ianphilip007]

all connections were correct as i say apart from the loose neutral found on 3pole isolator

 

[Wilko]

I'm guessing - loose meaning resistive, not disconnected, so still got some e flow ?

 

[snowhead]

If the new fan ran slow and caused the shower light to be dim, then the fan must have been in series with the light via the loose neutral.
Was the light neutral looped from the isolator?

Also was the old fan running slow, suggesting there was nothing wrong with it apart from a loose neutral?

 

[ianphilip007]

Probably correct to assume that the loose neutral was present or may have got worse leading to the failure of the old fan and downlight transformer. At time of replacement both 12v shower light and fan were not working at all. Fair to say that due to the new fan and light showing problems as above, before fault correction, shows that the cause of fan and transformer failiure may well have been the poor connection of the neutral conductor

 

[ianphilip007]

Impossible for me to now say if the loose neutral connection was the only fault and the fan/light transformer were not actually faulty. It could have been, fortunately, for the customer, they wanted a more powerful mixed flow fan fittng anyway.

 

[ianphilip007]

Light neutral ( via 20-60Va transformer) was looped from neutral at timer fan junctionjbox via neutral from 3 pole isolator switch