Atag IC36 & Hive Thermostat

[ianmcd]

then there is nothing wrong with the receiver, and if the boiler runs as you say then the wiring at the boiler is wrong too

 

[CBW]

Try wiring the receiver using some cable and plug top, see if it works then.

 

[ianmcd]

Try wiring the receiver using some cable and plug top, see if it works then.

He has #15 and it worked hence my post#16 mate

 

[CBW]

He has #15 and it worked hence my post#16 mate

Thanks mate, iPad was playing up at the time, wouldn’t load pages properly

 

[Ian_Rob]

I need to break off now as I have to work on something else. I‘ll have another look tomorrow.
Thanks for all the help.

 

[RandomGrinch]

Though a 3-core cable runs from the boiler to the Honeywell CM907 thermostat, the SwL isn’t connected at the Honeywell

believe that I need to connect the existing L & N from the boiler to the L & N of the Hive and the SwL to the Heating On (Terminal 3 ) of the Hive.

despite there being 230 volts at the L & N pins there

Did your original CM907 wiring look anything like this?:

 

[Ian_Rob]

Yes, exactly like this!

 

[ianmcd]

Yes, exactly like this!

Then DO NOT connect L&1 on the hive, the existing 2 wires go to 1&3 on the hive, do NOT put 240v in there, it might be connected to 24V at the other end and it will be a very expensive mistake if you get it wrong

 

[RandomGrinch]

Yes, exactly like this!

I'm afraid, that's the problem!
In the above image, the brown is live and the blue is switched live.
You don't currently have a neutral.
What is tricky - you would still measure 230V from the live, to the switched live.

If you can find where the cable connects to the boiler, you need to make the wire that wasn't connected (what you thought was switched live) into a neutral.
Post some photos of the connections to confirm.

Then DO NOT connect L&1 on the hive, the existing 2 wires go to 1&3 on the hive, do NOT put 240v in there, it might be connected to 24V at the other end and it will be a very expensive mistake if you get it wrong

I was writing the above as you posted - it is definitely worth checking, but as 230v was measured across live and switched live, I suspect it may be ok.

But again... Post some pics of the boiler connections!

 

[Ian_Rob]

Well I have just reconnected the Honeywell so that we have heating and hot water for the morning and thankfully it is working .

I will send some photos in the morning but I looked at the wiring connections yesterday and there is a 3-core cable connected to the L, N & SwL 230V control terminal blocks in the boiler (as attached image). The SwL is connected at the boiler but not at the Honeywell. The Earth isn’t used.

 

[Ian_Rob]

Herewith some photos of the wiring inside the Atag boiler and the Honeywell that I took before I started.

As you can see, the boiler installer used the earth of the 3-core as a SwL and marked it as such with brown felt-tip at the boiler end only. This seemingly however was never connected at the Thermostat and just left bare.

Also, the Atag terminal diagram, marked-up with the wiring connections that I tried last night without success.

 

[Mister Banks]

This all makes no sense. Maybe you have another faulty Hive receiver.

 

[RandomGrinch]

This seemingly however was never connected at the Thermostat and just left bare.

As I said, the blue wire in your CM907 is the switched live - if it wasn't, it would not work!

It appears that you have another junction between two cables somewhere.

 

[Ian_Rob]

As I said, the blue wire in your CM907 is the switched live - if it wasn't, it would not work!
View attachment 291804
It appears that you have another junction between two cables somewhere.

OK. Something odd here. I will investigate further. Thankyou!

 

[ianmcd]

Something very wrong there if that was wired like that a trip would have activated or fuses blown, and could never have worked