Bathroom light flickering when fan stops

[silentbrown]

This has just randomly started happening, a year after installation.

Turn on bathroom light: Light comes on, fans starts. All good!
Turn off bathroom light: Light goes off, fans continues. All good!

Fan timer finishes: Fan stops, light starts flashing at epilepsy-inducing frequencies! :<

Turn off fan at isolator, light switches on and off as expected.

Light is Philips LED (regular ES Screw)
Fan is Vent-axia Silent 100mm.

I've tried replacing the bulb, and instead of flashing, the bulb nows stays on, but dim. (Possibly the replacement is dimmable, and the original wasn't?)

I think it must be the fan that's died, which is annoying as I thought Vent-Axia was a decent brand.

[Shinysideup]

Sorry, not strictly related to your exact fan or setup but I had a relatively new Newlec 100mm fail recently. Found the timer potentiometer had failed and burned the PCB and cover. Probs best to keep it isolated until you inspect it.

Mine was pulsing the fan itself and not back feeding the light though.

Edit: I see that you can possibly alter a jumper setting to bypass/rule out the timer circuit depending on which exact model you have.
https://asset.eezybridge.com/nc/ba7b9546-29dd-40c4...

Edited by Shinysideup on Saturday 23 November 00:03

[tux850]

It'll be down to slight leakage on the switch live input, mostly likely due to poor design of the timer circuit (possibly being intolerant of the change of operating characteristics of ageing components noting that it hasn't always happened).

I hesitate to make any recommendation given we're talking mains voltages and not being able to rule out wiring/other issues, but an RC snubber (edit: better still a flying lead alternative would have fewer extraneous conductive parts) wired across the LED *should* dissipate the stray voltage and prevent the bulb flashing (which is down to its internal capacitor slowly charging until able to energise its internal power supply briefly at which point it disacharges and the process starts again).

Edited by tux850 on Saturday 23 November 01:13

[silentbrown]

tux850 said:

I hesitate to make any recommendation given we're talking mains voltages and not being able to rule out wiring/other issues, but an RC snubber (edit: better still a flying lead alternative would have fewer extraneous conductive parts) wired across the LED *should* dissipate the stray voltage and prevent the bulb flashing (which is down to its internal capacitor slowly charging until able to energise its internal power supply briefly at which point it discharges and the process starts again).

Good idea. I'll try the flying lead snubber first, as that's probably a lot less hassle than trying to return the fan under warranty.

[silentbrown]

silentbrown said:

Good idea. I'll try the flying lead snubber first, as that's probably a lot less hassle than trying to return the fan under warranty.

Scotch that idea... Just took the fan out and apart...


It's flexi ducting out to a tile vent, and the ducting is indescribably gross. Water condensing in the duct then dripping back down into the fan.

Think I'm going to be spending some time replacing the ducting, and seeing if a condensate trap is an easy install.

Any suggestions for replacement ducting?