Timer Wiring Problem

JOHNPT

Hello All - I am changing a faulty timer for a Glowworm Boiler with an APT timer. There is no valves or stats so its seemed fairly basic. I have a fused spur which feeds an APT timer - brown blue & green from fused spur is Live In (Brown), Neutral (Neutral) & Earth (green) too APT Timer - then i have a 4 core cable from APT too Boiler -
1 Black = Live Out (APT) = Switch Live at boiler,
2 Brown = Live In (APT) = Permanent Live Boiler
Neutral = Too Neutral

The problem is although the timer works and turns On/Off boiler the light on Timer stays on when its in off position -the light dims but still stays on. What am I doing wrong

http://www.glow-worm.co.uk/stepone/data/downloads_sd/8f/00/00/micron-80ff.pdf

Please see page 24 of the above for wiring diagram

M cebee

JOHNPT wrote: »

Hello All - I am changing a faulty timer for a Glowworm Boiler with an APT timer. There is no valves or stats so its seemed fairly basic. I have a fused spur which feeds an APT timer - brown blue & green from fused spur is Live In (Brown), Neutral (Neutral) & Earth (green) too APT Timer - then i have a 4 core cable from APT too Boiler -
1 Black = Live Out (APT) = Switch Live at boiler,
2 Brown = Live In (APT) = Permanent Live Boiler
Neutral = Too Neutral

The problem is although the timer works and turns On/Off boiler the light on Timer stays on when its in off position -the light dims but still stays on. What am I doing wrong

http://www.glow-worm.co.uk/stepone/data/downloads_sd/8f/00/00/micron-80ff.pdf

Please see page 24 of the above for wiring diagram

not sure prob nothing wrong just feedback
does boiler operate correctly
have you checked everything
what voltage on 1 when off

JOHNPT

Not sure of voltage on 1 when off I didn't check - but boiler seems to work fine - its just light staying on (but dimming) when turned off which seems strange. thanks

Bruthal

Check the polarity is correct, that can make neon indicators glow slightly when they have a live connected to them continously instead of a neutral, so check the brown and blue into the timer are actually live and neutral.

Other than that it could be a slight back feed or induction from the boiler switched feed. Them boilers are usually a loop you need to just close with volt free contacts, usually in the motorised valves, rather than a switched live into them.

bucky08

You could have a faulty frost stat this will make the light on the apt to light is the boiler coning on when apt set to off

2011

M cebee wrote: »

not sure prob nothing wrong just feedback

Exactly what I was thinking.
If everything is connected correctly you could get the APT timer to drive a relay. This would prevent any feedback.

2011

BTW the APT analog timers are very poor quality. You will be called back to replace it, just a matter of time. It would be better and neater to install a digital time clock. Siemens do a nice one.

Bruthal

2011 wrote: »

Exactly what I was thinking.
If everything is connected correctly you could get the APT timer to drive a relay. This would prevent any feedback.

Determining if its a backfeed can be done by temporarilly disconnecting the permanent feed into the boiler. If the neon goes off then with the timer off, then its likely a backfeed returning from the boiler.

It would have to be a high impedence one or inductance, because if there was a full live coming back, the boiler would be running.

In these situations, a polarity check is worthwhile, because a neon will light dimly when connected between an always on live (the reverse polarity neutral) and an open length of wire (the switched live, but switched neutral now with reverse polarity)

2011

+1

A small voltage can cause a neon to illuminate.

We investigated a situaion recently where mains volatage LED run indication lamps were illuninating on some MCCs when the phase supply to them was switched off. It turns out that even though they are rated for 230VAC at a voltage of less than 2V they illuminate quite brightly.

paddymick

Ive seen this problem in APT clocks a few times and just replaced them and all was fine so it must be an internal fault in the clock.

The old original model apt clock isnt the worst clock in the world and if used right should last years.They brought out a newer version over the last few months but there where alot of complaints about the noise of them so my wholesaler has gone back the selling the original one.

Alot of people prefer them over digital because they are easier to use.Landlords especially seem to like them as they dont need to explain how they work.

I personally try to push for a digital clock especially since there is not much differance in the price.

And like 2011 said the siemens digital clock is a great clock,Ive never had an issue with one and thats the way I would be going if I was the OP.