Old boiler turning itself on at night

[Rossjm]

Hi all,

Strange query here...! I recently replaced my timer/programmer thanks to the help of folk on here.

I now have a Drayton lifestyle 7 day programmer, a Honeywell junction box, and a very old but well serviced and working Potterton Kingfisher MF boiler.

Recently (Not just when cold outside) the boiler has been kicking in at night and waking us up as the radiators are at full tilt / heat, this despite it not being set to come on at these times. To try and establish what is wrong I turned the old school thermostat down to zero last night, and the boiler still kicked in, clearly somehow ignoring the thermostat also...

Any idea what on earth could be happening? From memory my missus who went down to turn off the power to the boiler doesn't seem to think the programmer was showing as lit up/on.

So we have a boiler which is turning itself on and bypassing the programmer and thermostat... wtf?

setup below, programmer has been working fine for a few months until these issues have started.

 

[Gasmk1]

do you have a frost stat anywhere

 

[Gasmk1]

you may need to check you wired it correctly

 

[Rossjm]

Hi,

I’m not sure what a frost stat is, from reading it kicks in to stop everything freezing, however it didn’t do it when i had 15’’ of snow the other week and minus 5, and has this week when it’s quite warm.

The new controller was just a straight swap using the same backplate etc and I got a relative who’s an electrician to do it, and it’s been totally fine for a few months with no issues until now?

Any other ideas? It HAS to be a faulty drayton programmer right?

 

[Rossjm]

Why would the thermostat dial be turned right around clockwise to zero yet the heating still kicks in? Surely if for some reason the programmer kicked the boiler in then the thermostat should stop it heating with it being turned off?

 

[Riley]

Is thermostat wired backwards

 

[Gasmk1]

are you sure the clock was a stright swap the wiring might be slightly different

 

[Rossjm]

I’ll double check that the wiring was the same, but i’m almost certain it’s been working fine and then has started playing up just now which makes me think its fine?

Perhaps unrelated - the boiler casing is now extremely hot when it’s on, and the radiators are too hot to touch - this has just started today.

What could this (perhaps seperate) issue be??