Thermostat wiring is blowing my mind

23 Jan 2021
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United Kingdom
Hey hey folks

I’m hoping someone can help me out.
I paid an electrician to come round and put in a new thermostat (hive) as part of a group of things I had done all at the same time.
Only issue is that I can’t get the central heating to come on.
When hive tries to switch on the heating.. I hear a click.. of the boiler completely switching off.
When I set lower temp on thermostat to ‘switch off’ heating.. boiler switches back on again.
When the (combi) boiler is on the water works etc.. my gut is that thermostat is wired wrong?
I’m hoping it is an easy fix as it’s currently -3 outside and I’ve just got home
I know I should call the electrician and get him back.. but if it’s a quick fix

I have tried to attach a picture
thanks in advance


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Really need to know a lot more about the system and how it is wired up but if you paid an electrician to do this I'd be getting them back.
It was one of many things actually I was getting him to do.
Just stupidly never tested at the time and I’ve been at family ever since it was put in due to covid shenanigans
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Thanks Flameport.
I’ve just tried it.
It had the opposite effect on this setting
Boiler had no power.
Then when hive tried to switch on heating.. it turned on the boiler.. but no heating turned on. Just the pilot light came on for hot water.
Thanks anyways
Does it light up on the receiver for heating? Might be that it is wired wrong, and you’ll probably have to get him back.
It was wired wrong as you shouldnt have anything in terminal 2 of the hive , post a pic of your boiler control panel, wht previous controls did you have ?
Boiler had no power.
Then when hive tried to switch on heating.. it turned on the boiler.. but no heating turned on.
Wired wrongly at the boiler - that brown wire is providing power to the whole boiler, rather than the connection that turns the heating on.
Terminal 2 is for heating off and is rarely used. Terminal 3 is heating on.
Whoever installed it was totally incompetent.
Thank you for the input folks.
I had guessed he had wired it wrong somehow.
Seemed odd that the timer/thermostat would switch off the whole boiler.
As I understand you shouldn’t switch that on and off all the time.
So the problem seems to be faulty wiring under the boiler cover?
Is this something I can fix?
Or is it only a gas man that can do it.
I could get the guy back again but do I really want him back.
Ianmcd I’ve attached a picture of the boiler control panel.. or at least I think I have unless you mean one inside the boiler
Thanks again


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Forgot this


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To be honest you’d be better getting a gas man out for that boiler, as it forms part of the room seal. I have also noticed that red link is doing nothing at all, you’d need to work out which wire is which. It’s a shame you’ve paid the electrician for that as they’ve now left you without heating.
What was used to turn the CH on before?

Can I also recommend that you turn the heating temp down too. Ideally keep it around 4-5.
Thanks Chris.
Yeah it’s rather annoying really.
There is a button on the front of the boiler which I believe is the ‘central heating boost’ button. it heats the system once and then it switches off again. It’s not even enough to heat the system. I could probably warm the house if I stood next to the boiler and pressed the boost button every five minutes.
Though thankfully it does allow me to get some heat and keep the cold/frost out of the system
Madrab it was a different thermostat before. Just a basic turn dial one.
The boiler was actually moved too which is why maybe the boiler is now wired wrong I guess.
Still, I think I will get someone different to do it instead of getting the other guy back again. I’m wondering if he would just wire it wrong the second time and me not know
I was hoping I could save the call out and do it myself.. but maybe you need the appropriate skills
Going by the behaviour of the boiler (powered off when stat and then powers on when the stat is turned on (now the wire's been moved to T3)) then it would suggest that the wiring in the boiler is missing 1 thing.
Ideally though your boiler should be always on and it then uses a switched live to turn the CH on and off. Ultimately that's where the issue is.

Unfortunately, it needs to be a gas registered engineer to take the case off the boiler up and wire it correctly as they have the equipment to ensure it's sealed back up properly. Who wired the hive into the boiler, it shouldn't have been the electrician.

I wouldn't play about with it yourself as there is the possibility of wiring it incorrectly and blowing the board.

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