Replacing a WC fan. Run on timer does not operate.

[arildthegreat]

I am planning to replace a fan in a small WC with no window as part of a redecoration. Having removed the cover to see what’s what, I see that it is meant to have a run on timer but it does not operate like this (It is an old Loovent Airflow). The fan is operated by the light switch and has a 2 pole isolation pull cord, with neon indicator, adjacent to the fan.

Operation is as follows:

Isolator ON: light switch turns on lights and fan runs. Light switch OFF: neon goes OUT and fan stops (no run on, I have tried adjusting the timer dial but this makes no difference).

Isolator in OFF position: light switch operates lights only, no fan (no neon)

I would plan to replace with a new timer fan giving the wiring that’s in place. Fan has connections for live (red), Trigger (yellow), neutral (black), earth (g/y). Apart from a duff timer, what could be the problem?

Thanks for you advice.

 

[EFLImpudence]

Apart from duff timer - not wired correctly ???

Has it ever worked properly?

 

[arildthegreat]

Never worked properly. Recent(ish) house move. And I actually like the way it currently operates but understand that a timer is required in such areas.

Should the fan pull cord neon go out when the light switch is turned off?

 

[EFLImpudence]

Should the fan pull cord neon go out when the light switch is turned off?

I would think so, yes.

Seems as if the switch is just to turn off fan when not wanted.
I.e. quick one in the middle of the night.

Fit the new fan and see if it works properly before fiddling with anything else.

 

[Electrifying]

Should the fan pull cord neon go out when the light switch is turned off?

They rarely have a neon, (although I know some do).

The light switch shouldn't turn off the neon in the fan isolator - only the isolator switch should do this.
I've never used one with a neon but I'm guessing that it's supposed to be bridged across the permanent live and neutral (as opposed to the switched live from the light switch), so maybe you've got your lives crossed, resulting in the wrong operation of the fan and the neon going off when the light switch is switched off.

Or even more likely, the person who installed it hasn't known where to take a permanent live from, so both live feeds are taken from the (switched) lighting circuit - which would result in no run on.

Only a thought.

 

[securespark]

You need to rewire to take a L, SL & N to the fan via a TP switch.