Replacing extractor fan - strange problem

[marknw]

Hello and happy new year. Hope someone can help with an odd issue please.

I'm replacing an Xpelair extractor fan in the loo witn an Airflow Icon15.

Problem is, the new fan runs at about 0.5 revs/sec, and i dont understand why.

If i connect it to a 3 pin plug it runs normally, but wired up in the loo it doesn't. 

Voltage in the loo is 242v, like the wall socket, so there isn't a transformer anywhere. 

Any ideas please?

Supplementary question - assuming problem is solved: I'd like to add the 2-minute delay module to the fan, but this requires L, N and T feeds and there are currently only L and N: can I legally add another live, or is that an electrician's job?

 

[ProDave]

Check where the fan is mounted that the fan blades are completely free to rotate.  I have known it where the fan, once mounted in the wall, something presses on or otherwise distorts the housing so the fan blade becomes stiff to turn.

To get a permanent L for the timer function replace the 2 core & earth with a 3 core and earth.  

 

[Evans Electric]

Any ideas please?

Supplementary question - assuming problem is solved: I'd like to add the 2-minute delay module to the fan,

Just thinking ,  if the fan runs OK from a temporary connection  there could be a problem with the wiring from the light ...fan in series with lamp or something daft.  

As Dave says ,  get a three core cable  from the light to the fan .    When you say  " 2 minute delay "   are you thinking of the delayed action on the fan when someone only takes a pee in there but doesn't want the fan running  ..or .. the fan over- run  module  ..?   If its the over - run may I suggest more than 2 minutes  , more like 20 minutes. 

 

[marknw]

Thanks for your replies. It isn't the mounting that's the problem - I've tried with the fan in my hand.

I'll see if i can work out what's happening with the wiring from the light, though it's not v accessible.  I suppose it's possible that if it was wired in series the old fan would have worked OK but new one doesn't?

Delay - yes, it's the pee delay I'm thinking of!

 

[marknw]

Rooted around in the roof cavity and found a redundant run-on timer, presumably left over from a previous fan installation. Problem solved! 

 

[roys]

Rooted around in the roof cavity and found a redundant run-on timer, presumably left over from a previous fan installation. Problem solved! 

Don’t think you have solved the problem as you said you wanted a delay on timer not a delay off timer. Plus none of this accounts for the slow turning.

 

[Evans Electric]

Problem is, the new fan runs at about 0.5 revs/sec,

 The old fan wasn't a low voltage one  12V   by any chance ?