My boiler is coming on during the night…

StanleyHiggins

My (wired) controller is programmed as follows:

08:30 - 16:30 19 deg
16:30 - 22:00 20 deg
22:00 - 08:30 16 deg

The boiler is in an outhouse (built onto the house).  When we have noticed the radiators pumping heat out in the night we always check the controller and it is NOT asking for heat.

The outhouse’s temperature last night for example was down to 9-10 deg.  The frost setting on the boiler should be 5 deg, so that shouldn’t be causing the issue.

Anyone got any ideas please?

born_again

Where is the stat?

MeteredOut

One potential issue could be the frotst-detection thermistor on the boiler is broken, so the boiler is kicking in over night.

Have you analysed the issue in more detail?

- Do you know how long its coming on for overnight? If you have a smart meter and have connected one of the apps (eg, Loop) it will give a rough indication of usage
- Is it at the same time each night and for the same amount of time?
- Could you unwire the controller from the boiler to see if the boiler still comes on overnight?

Are you sure your controller. only has 3 time slots (ours has 4). What model is the controller?

PS. You might want to consider asking your post to be moved to the main energy board, where it will likely get more views - use the "Report" button to do that.

FreeBear

System (or heat only) boiler - It may be the thermostat on the hot water cylinder calling for heat and you have a stuck 3-way valve. Or if it is an old gravity fed system, no valves at all (my old system was like that).

A combi boiler - Possibly a fault with the timer or inside the boiler.

StanleyHiggins

Answers:

1 - the stat is in the house at the bottom of the stairs.

2 - no we haven’t analysed it in more detail.  We don’t have a smart meter.  We could unwire the controller from the boiler but am unsure about that.  Our controller has 4 slots too but we only use 3.  It’s a Drayton Digistat-06FD with remote control via an app.  Thankyou for the suggestion to move the post.  I will do that.

3 - it’s a combi boiler.

born_again

Has stat a temp setting that is conflicting with controller settings causing it to kick in?

BobT36

I had this once, and changed the batteries in the thermostat. It then stopped.

StanleyHiggins

Born_again - I don’t think so - I’ve reset the timings via the app just to make sure.

BobT36 - we changed the batteries not long ago.

thanks for your suggestions.

cannugec5

what is the temperature set at between 8.30 pm and 8.30 am? 

Is that when it is dropping down to such cold levels? The thermostat is not telling it any different. 

StanleyHiggins

Cannugec5 I’m not sure what you mean?  The controller settings are in my original post.

EssexHebridean

I assume your controller/thermostat shows you when the heating is actually running? If so, what does it show when you look at it in the night. (I realise you said that it wasn't calling for heat at those times, but I'm curious to know whether it actually shows that the heating is running, or whether it seems that the issue is completely disconnected from the controller.)

You might also try overriding the temperature set for overnight right down to 8 or 10 degrees and see if that makes a difference.