Heating control question with an oddity

[CountryFan]

It a steam powered mechanical timer!

Steam power?

 

[ericmark]

Steam power?

So likely a flash over as contacts open, still an EMC fault. There should be no connection between a smoke alarm and the heating, but cables can run in proximity to each other. The SPD should stop any spikes, but older consumer units don't have them fitted.

Cheap options first

or use an extension lead and plug the central heating into another socket, I would have a problem as my central heating uses a FCU, silly idea really, as it means can't unplug it and plug it into a power bank with mains failure, but my central heating is only item in the house not RCD protected, which is why mine does not use plug and socket.

If the smoke alarm and central heating on the same MCB/RCBO I would be looking to see if can be separated.

I’ve swapped the alarms - previously the optical alarm with 9v battery backup to multi sensor fire alarms.

That would have been my first thing to do as well. I would say the problem is done to alarms not the central heating.

 

[CountryFan]

Still happening since me changing the alarms. Going tomorrow to change the programmer and get an electrician too.

So an update on this: I didn’t attend the following day due to a planning ballsup. Electrician attended today and mentioned something to do with a voltage difference (so the customer told me). Anyway, I attended late afternoon and changed the mechanical programmer for a digital type, tested to ensure working and not causing an issue. After a few up and down turns of the thermostat I heard an odd noise, a bit like a stuck record maybe, and the alarms sounded for about 5 seconds. Changed the mechanical thermostat like for like and did the same test and they didn’t sound. Only time will tell if it recurs. Hope not!

 

[ericmark]

Glad it seems sorted, these faults are a real pain, as I, for one, do not have the equipment to monitor what is going on. Yes, I know I should have it, it is a requirement of my licence, and I do have a wave meter, but it's a long time ago when I took my RAE.