Flashing LEDs when fan and lights off

clanky boy · Aug 5, 2023

Good afternoon everyone.
I have fitted an extractor fan in my bathroom with an overrun timer, to start when the bathroom led lights are turned on. I have wired the feed to the fan via an adjustable overrun timer and DP isolator with the SL for the fan timer coming from the light switch.

The issue is with lights and fan off the LEDs are flickering dimly - this stops when the DP switch is opened. I assume there is a small leakage to N from somewhere in the timer causing the sensitive LEDs to flicker, which when the DP switch is opened cannot occur hence the flicker stops.

I have bought and fitted a 47nF 100r capacitor and connected it to all possible combos in the timer - no change. The only thing that stops it is if I disconnect the SL from light switch yo timer - but obviously the fan wont run now.
I have spoken to a qualified sparky who's only suggestion was the capacity action as a snubbed - he doesn't know what to do now!

I am stumped and would appreciate any advice please.

clanky boy · Aug 21, 2023

marconi said:
I drew the zener diodes connected the wrong way round in my first post. To block the +14V they need to be as in the sketch attached.

Good afternoon Marconi, when I get the diodes what type of enclosure do I pit them in - a small wago box with heat shrink on diode tails into wago connector/chocolate block?
Many thanks, Mark.

Avo Mk8 · Aug 21, 2023

Hi
Apologies for chiming in on this.
It occurred to me if you are using the Manrose 1351 back box supplied with it, that's an enclosure that you could use right away!
Probably a good idea to sleeve the leads of the diode, though doesn't have to be heat-shrink!
You could put the banded end of the diode in the SL terminal of the Manrose, and stick a single choc block, or 2 hole Wago on the other end of the diode, and add the wire that was previously in the SL terminal.
Or a more elegant and robust method (for the diode) would be to put the diode across the terminals of a twin choc block, and then wire that to the SL terminal and the switch cable.
That all assumes there is enough room amongst the wiring already in there!

[ElectriciansForums.net] Flashing LEDs when fan and lights off

clanky boy · Aug 21, 2023

Avo Mk8 said:
Hi
Apologies for chiming in on this.
It occurred to me if you are using the Manrose 1351 back box supplied with it, that's an enclosure that you could use right away!
Probably a good idea to sleeve the leads of the diode, though doesn't have to be heat-shrink!
You could put the banded end of the diode in the SL terminal of the Manrose, and stick a single choc block, or 2 hole Wago on the other end of the diode, and add the wire that was previously in the SL terminal.
Or a more elegant and robust method (for the diode) would be to put the diode across the terminals of a twin choc block, and then wire that to the SL terminal and the switch cable.
That all assumes there is enough room amongst the wiring already in there!View attachment 110082

Thank you - I will try the double choc bloc option, I think there will be room. I wasn't sure if there would be any heat generated by the diode.

Many thanks Mark.

Avo Mk8 · Aug 21, 2023

clanky boy said:
Thank you - I will try the double choc bloc option, I think there will be room. I wasn't sure if there would be any heat generated by the diode.

Many thanks Mark.

No heat. Good luck!

marconi · Aug 21, 2023

Zener Diode Vector Illustration Isolated On Stock Vector (Royalty Free) 2137075083 | Shutterstock - https://www.shutterstock.com/image-vector/zener-diode-vector-illustration-isolated-on-2137075083

Zener diode markings to identify which way round to connect it.

marconi · Aug 22, 2023

Clanky boy - good evening Sir.

I was pondering one of your earlier posts which included a wiring schematic. I have included it is an attachment below.

In my blue balloon marked X do you in reality have three wires going to the single pole light switch?

I have another very simple idea to solve the problem.

Others might like to ponder it.

Avo Mk8 · Aug 22, 2023

marconi said:
Clanky boy - good evening Sir.

I was pondering one of your earlier posts which included a wiring schematic. I have included it is an attachment below.

In my blue balloon marked X do you in reality have three wires going to the single pole light switch? I have another idea to solve the problem.

Others might like to describe it. There are at least two ways of doing it.

Not my post #60 by any chance?

nicebutdim · Aug 22, 2023

marconi said:
Others might like to ponder it.

I take it something so simple as taking that switched live from the JB, rather than the switch, would have no impact?

marconi · Aug 22, 2023

Note to self - read all the earlier posts carefully before trying to be a clever dick.

Mike Johnson · Aug 22, 2023

The OP Was advised early on that the switched live from the Manrose is automatic and the cable from the switch was not necessary, the connection ought to be from the Manrose timer to the fan, but the fan also has an internal timer which to my mind makes confusion for the Manrose unit.

clanky boy · Aug 24, 2023

Mike Johnson said:
The OP Was advised early on that the switched live from the Manrose is automatic and the cable from the switch was not necessary, the connection ought to be from the Manrose timer to the fan, but the fan also has an internal timer which to my mind makes confusion for the Manrose unit.

Mike, i don't undestand the 'Manrose S/L is automatic' - it needs a S/L input to function, hence the connection from the light switch. The fan and built in timer are not confusing anything, as they are effectively 'dumb' with the built timer set to max run on of 30 mins, and the actual run on time being controlled by the Manrose 1351cutting the permanent live.

Nicebutdim - taking the S/L from the JB is essentially the same as taking it from the switch so would still allow a path for the V to the leds, sonkoving it wouldmake no difference I'm afraid.

Everyone - I think i have found the issue. The manrose timer has 146v on the S/L terminal after the light switch is off - this is feeding back via the S/L in the switch to the led lights.

All the other other manrose 1351 timers I have in place elsewhere and working (6 in total) are showing voltages between 96v and 135v. I intend to install a 200v zener diode in this circuit see if this solves it.

I'll let everyone know how I get on. Diode due here tomorrow.

Regards Mark.

Avo Mk8 · Aug 24, 2023

clanky boy said:
Mike, i don't undestand the 'Manrose S/L is automatic' - it needs a S/L input to function, hence the connection from the light switch. The fan and built in timer are not confusing anything, as they are effectively 'dumb' with the built timer set to max run on of 30 mins, and the actual run on time being controlled by the Manrose 1351cutting the permanent live.

Nicebutdim - taking the S/L from the JB is essentially the same as taking it from the switch so would still allow a path for the V to the leds, sonkoving it wouldmake no difference I'm afraid.

Everyone - I think i have found the issue. The manrose timer has 146v on the S/L terminal after the light switch is off - this is feeding back via the S/L in the switch to the led lights.

All the other other manrose 1351 timers I have in place elsewhere and working (6 in total) are showing voltages between 96v and 135v. I intend to install a 200v zener diode in this circuit see if this solves it.

I'll let everyone know how I get on. Diode due here tomorrow.

Regards Mark.

The 146V doesn't really tie up with the previous measurement you mentioned. Is it ac or dc?
It sounds like the circuit in the 1351 is different from that in the fan run on timer (which is probably a good thing!)
If your other Manrose timers are giving a similar voltage, are they not in parallel with LED bulbs and making them flash?

At this point I'd go for the double pole light switch solution.
I know, I know, you've got a brushed platinum light switch plate and can't possibly change it!

I suspect a 200v zener might not provide enough of a step change to operate the timer, but worth a try I guess.
Sorry the efforts so far have not fixed it.

marconi · Aug 25, 2023

If zener does not work we can use current single pole switch plate to control a mains coil relay with double pole Normally Open contacts like this one:

Finder 66.82.8.230.0300 - 30A Flange Mount Power Relay 230VAC DPST-NO - https://www.rapidonline.com/finder-66-82-8-230-0300-30a-flange-mount-power-relay-230vac-dpst-no-49-3969

clanky boy · Aug 28, 2023

marconi said:
If zener does not work we can use current single pole switch plate to control a mains coil relay with double pole Normally Open contacts like this one:

Finder 66.82.8.230.0300 - 30A Flange Mount Power Relay 230VAC DPST-NO - https://www.rapidonline.com/finder-66-82-8-230-0300-30a-flange-mount-power-relay-230vac-dpst-no-49-3969

Mr Marconi, Avo mk8, Mike and everyone else - the 200v zener has sorted it - thank God.
I'm now off to have 10 pints!!!
On a serious note, thank you to everyone that have chipped in, added value, and acted as a sounding board - you have all worked through this with me, putting up with my rubbish diagrams.
Thank you all again, and hopefully i won't need to bother you guys again,
Kind regards,
Mark.

DPG · Aug 28, 2023

clanky boy said:
Mr Marconi, Avo mk8, Mike and everyone else - the 200v zener has sorted it - thank God.
I'm now off to have 10 pints!!!
On a serious note, thank you to everyone that have chipped in, added value, and acted as a sounding board - you have all worked through this with me, putting up with my rubbish diagrams.
Thank you all again, and hopefully i won't need to bother you guys again,
Kind regards,
Mark.

Have an extra pint for me. Glad you got it sorted. Just shows there are some clever people on here. And me of course

Flashing LEDs when fan and lights off

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