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Central heating timer causing a short

Kashkai

The power in the house went on the blink for a second this morning for no apparent reason. A few minutes ago, I just happened to check to see if the heating was set to come on in the morning when I noticed that the timer clock had stopped at the point where it switched itself off this morning. I'm guessing that this caused the short in the power supply. I base this "theory" on the fact that we had a very similar problem with this type of timer when we first moved into the house as it would cause the power to trip when it switched itself off.

The timer is one of those simple analogue ones, i.e. a round white dial with little pins you push in to set the on/off times. How easy would it be to trouble shoot this problem to be 100% sure it is the timer? If it is the cause of the power tripping, how easy would it be to replace it with a digital timer? I've been checking online and I'm getting confused between one channel, two channel etc etc. Which one would I need?

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ShamFeen

Ok your timer is probably an APT timer. How many timers have you? These are one channel analogue timers. The number of channels you need, depends on how many zones you have.

e.g in ahouse there may be three zones, so you can turn on upstairs heating seperate to hot water and downstairs independant of the other two e.t.c. It sounds like your heating isn't seperated. Just to confirm this, do all your heating (rads) and hot water come on together??

So your circuit breaker (m.c.b) is tripping when you switch on your heating??
If this is the case to check if timer is faulty. Make sure power is off and open off the clock. There are three connections. They are labelled on the bottom, something like l1 or l in, n, and l out or l2. Leave the neutral connections alone and disconnect one of the lives and put it in the connector with the other live. Now switch on and see what happens?? The timer is now bypassed so if you still have a problem it's probably your boiler.

BE CAREFUL AND SWITCH OFF POWER!!!!!

Kashkai

Should have mentioned that the heating will work when the clock is manually switched to "on", i.e. the heating will come on. Its the clock part that appears to be broken, i.e. it won't move (the dial doesn't rotate as it should).

meercat

prosperous dave
thats some run of problems your having with your heating systems
i would say its unusual for the timer to cause the problem your having.when the clock switches off it should break the circuit and not "blow" the clock.i would suspect that something else is shorting out(perhaps pump) and causing problems for your timer.i would advise not to replace clock until you resolve this first
when you say "on the blink",what happened?
did a fuse blow?
did a tripswitch activate?
cheers

Kashkai

meercat wrote: »

prosperous dave
thats some run of problems your having with your heating systems
i would say its unusual for the timer to cause the problem your having.when the clock switches off it should break the circuit and not "blow" the clock.i would suspect that something else is shorting out(perhaps pump) and causing problems for your timer.i would advise not to replace clock until you resolve this first
when you say "on the blink",what happened?
did a fuse blow?
did a tripswitch activate?
cheers

"thats some run of problems your having with your heating system"

You don't know the half of it:mad: The plumber and sparks involved in my house build were complete eejits!

I had the pump replaced last December when it was causing the MCB to trip. I checked the pump this morning and all the wires are in place and dry.

This time round, the MCB hasn't tripped at all but there was a momentary (i.e. a second) of interuption in the electricity supply when this clock switched itself off for the last time Sunday morning. The clock works (and the heating) when manually switched to on or off. Its the dial/timer thats gone. I checked the wiring today and all appear to be correctly in place with nothing loose.

Its an APT timer btw. I've done a search on Boards and there are a few threads where something similar has happened, e.g. timer has stopped but it will switch on and off manually. I'll get a new timer tomorrow, don't know if I'll stick with another manual or get a digital one.

Avns1s

It's quite common that the clock part of these stop working. In 5 years, I have replaced three times. Seem to last little over a year. I put in a relay, thinking it was the starting load (small motor) was doing something to the timer. No improvement. I wouldn't have used apt only that I had them "in stock".

Anyway, when it goes again, I will be moving to a single channel digital timer.

meercat

probably the last fault to sort so
but your title says "causing a short"
maybe just faulty timer if nothing is blowing or tripping
i have noticed some of your previous posts alright
cheers

Joey the lips

My pin and dial clock has gone twice in 5 years. Quite common it seems. Will always stick with them though as they are easy to explain to most parents and babysitters....

* Except my mom. She is a plonker with tecnology

Kashkai

How easy is it to wire up a replacement single channel digital timer, i.e. simple earth, neutral, live etc or does it involve bridging contacts?

Avns1s

It will depend on tha model, some can require bridging and some dont.

Fire ahead, get your digital timer and come back with the model and someone will sort you out.

One thing though, you will be fitting it over a "flush" box? In other words, a recess in the wall. The digital timers generally are close on twice the width of a single flush box. They fit "onto" a single box but are twice as wide, if you get my drift.

Just make sure you have the space for the model you get.

Sorry for the rubbish explanation of this but hopefully you can follow my point.

Buford T Justice

Hi Dave

This is the one to use. It's a Grasslin and readily available from most electrical wholesalers. Get the QE1 and not the QE2, as the latter is to control the immersion as well. I fitted it in my own house years ago and it gives no trouble

Its very simple to install, but takes up a twin socket space. There is one pole you need to bridge, L to 3, but thats it. It comes with all the instructions you need, but if its just to control the boiler and pump, which i suspect it is, then its an easy job. let us know which one you go for

Kashkai

Thanks for the replies guys.

I have loads of room on the wall where I plan to put the new timer so thats not an issue.

I called into a couple of plumbing suppliers to see what they had in stock. My local place in Prosperous had a "Terrier" model for €72 while Barretts in Maynooth had a "Danfoss" model for €80. Are these ballpark prices or can I do better? Btw, they both had simple analogue models similar to the now defunct APT timer for approx €35 but I wasn't interested.

If I need to bridge contacts, I presume that I can use a simple strip of electrical wire or does it have to specially rated for the load?

Buford T Justice

Prosperous Dave wrote: »

Thanks for the replies guys.

I have loads of room on the wall where I plan to put the new timer so thats not an issue.

I called into a couple of plumbing suppliers to see what they had in stock. My local place in Prosperous had a "Terrier" model for €72 while Barretts in Maynooth had a "Danfoss" model for €80. Are these ballpark prices or can I do better? Btw, they both had simple analogue models similar to the now defunct APT timer for approx €35 but I wasn't interested.

If I need to bridge contacts, I presume that I can use a simple strip of electrical wire or does it have to specially rated for the load?

I think you're being had there Dave. Just called my local wholesaler and the QE1 is €45 including the vat, and its a digital timer, with the ability to time different settings for weekdays and weekends.

In terms of bridging contacts, whatever gauge the cable supplying the boiler and pump will be fine, and is either 1.5 or 2.5

Kashkai

Oh I don't doubt that I'm being had Fingers but East Coast prices are usually higher than the West. My wife is from Mayo and I'm always shocked at how much cheaper some items are down there compared to what is charged in Dublin/Kildare.

Any idea where I could do better in terms of price at my end of the country?

Buford T Justice

Prosperous Dave wrote: »

Oh I don't doubt that I'm being had Fingers but East Coast prices are usually higher than the West. My wife is from Mayo and I'm always shocked at how much cheaper some items are down there compared to what is charged in Dublin/Kildare.

Any idea where I could do better in terms of price at my end of the country?

Not sure what you have in the east, but I would suggest Heatmerchants. There's one in Toughers business park in Naas.

Chadwicks are on the Newbridge road from Naas.

City Electrical Factors, they are in the N7 Business park in Naas.

I know that our Heatmerchants stock them, so they should over there too, and Chadwicks are another plumbers merchants.

City Electrical Factors are here too, and are generally on a par with the wholesaler I deal with here too price wise, so they should all be worth checking out.

Best of Luck

cozar

do you need an electrician or could someone with litte diy knowledge do it? my clock on the timer is an analogue one and has stopped so no heat coming on in the morning unless i turn it on manually.