Central heating problem.

[Stoffel]

Hi Folks,
Any advice/assistance would be much appreciated on this painful problem!

My Honeywell programmer is jumping from "Off" to "Auto" automatically, randomly and seriously annoyingly!
I have replaced the programmer but no joy.

Any thoughts?
Stoffel

 

[littlespark]

Is it a mechanical time clock or an electronic programmer? A photo would be good or the model number.

 

[Gas engineer]

Is it wireless? New batteries perhaps?

 

[EricMark]

Since nearly a week and no reply assume fixed? However I did look at the

I have replaced the programmer but no joy

And so would be looking at a EMC problem, i.e. some thing else in the home producing a strong signal which is upsetting the programmer, as a radio ham this is a common problem, with car alarms, and security lights going off when they shouldn't.

I have been told the fans in some boilers can upset some RF linked thermostats, so it needs some careful notes as to when it happens, be is a baby alarm, or use of mobile phone, likely some thing is causing it, and it can be a pig to find.

I had it in a factory, causing machines to do daft things, I banned mobile phones, if anything found problem was worse, then found some one was hiding their mobile inside an electric panel.

 

[Stoffel]

Thanks James for your thoughts, it certainly looks like a transient overvoltage or eddy current, although I cannot find the source directly.

1. A family of 5 and we all have mobile phones...who doesn't
2. One would think that a rewire of the boiler supply is the one option left, however, that's not a guarantee.
3. There is no pattern to it...as random as anything.

I am now thinking of wiring the heating switch wire through a manual switch next to programmer. That way I can be sure the heating won't randomly want to come on when it picks up this transient voltage. Keeping the room stat down to a low temp is not a fail-safe option for me!

Thanks so much for your time and thoughts, much appreciated.

 

[davesparks]

Is the programmer making proper electrical contact with the backplate? Was the backplate replaced at the same time as the programmer?

 

[Stoffel]

Is the programmer making proper electrical contact with the backplate? Was the backplate replaced at the same time as the programmer?

hi Dave
1. Yes to contact, and yes to replacement of back plate, as much as one can tell as fastened with both securing screws at bottom of programmer

 

[davesparks]

hi Dave
1. Yes to contact, and yes to replacement of back plate, as much as one can tell as fastened with both securing screws at bottom of programmer

If the backplate is flat and firmly fixed then with the securing screws done up the programmer will be making good contact.

It was just a thought as I've seen odd behaviour like this from poor contact causing momentary power loss to programmers.

Have you contacted honeywell technical support to see if they can shed any light on this odd behaviour?

 

[Stoffel]

If the backplate is flat and firmly fixed then with the securing screws done up the programmer will be making good contact.

It was just a thought as I've seen odd behaviour like this from poor contact causing momentary power loss to programmers.

Have you contacted honeywell technical support to see if they can shed any light on this odd behaviour?

Thanks Dave, you are right. Bad contacts could be the problem. Redone wiring Centre with that in mind.
Honeywell said they've experienced this problem and the insertion of a capacitor would normally help in suppressing or absorbing the over voltage. To be honest I think it made it worse. I removed it and the problem is less frequent now! Go figure

 

[davesparks]

Thanks Dave, you are right. Bad contacts could be the problem. Redone wiring Centre with that in mind.
Honeywell said they've experienced this problem and the insertion of a capacitor would normally help in suppressing or absorbing the over voltage. To be honest I think it made it worse. I removed it and the problem is less frequent now! Go figure

Did they elaborate on the supposed overvoltage? It would be interesting to know where they think it could be coming from or what voltage it may be?

This is ounding like its something unique to honeywell and changing to another brand of programmer may cure it. Personally I've always found Drayton LP series programmers to be pretty reliable, the LP522 suits most people's needs.