Lifestyle LP241 replaced with Hive CH issue

[LordWhiteley]

Greetings. Having studied many of the threads on here replacing the Lifestyle LP241, I decided to buy a dual channel Hive receiver + Thermostat and replace my LP241.

Hive version - Hive Thermostat for Heating & Hot Water Control (Conventional Boilers), With Hive Nano 3 Hub, White, A Conventional Boiler is Required

On the LP241 programmer terminal block, the connections were N, L, HW off, HW on and CH on. There was NO connection for CH off (Pin2). I did a 1:1 wire swap on the Hive unit.

I traced the mechanical thermostat wiring back to the wiring box in my airing cupboard and linked the wires together with a short piece of wire (so linked together on the terminal block and wires open circuit where the thermostat was.

Everything sort of works.. HW works fine however CH will only come on if HW is on. So if I press the CH button the on the Hive control unit (turning green) nothing happens unless I press the HW button at which point the boiler fires up and radiators come on. As soon as I turn off HW the boiler shuts down???

I did an AI query which suggested I had the Hive in the wrong mode but I think green means pump mode which is correct and I had already shorted out the thermostat (before I did this, I temporarily set the mechanical thermostat to the maximum 30degC). The final suggestion was a faulty micro switch on the 3-way valve, although that would be a coincidence that the switch failed at the same time as swapping over to the Hive unit. I do however have a spare Honeywell 3-way valve I could use. Luckily, i fitted one one where you can separate the motorised head from the brass valve some years ago, so it would be easy to unwire the current version and swap it with a new one.

I wonder if some wiser folk on here have any suggestions??

Cheers John

 

[CountryFan]

Sounds like a wiring fault. Can you post a photo of the Hive wiring?

 

[LordWhiteley]

OK Here are photos of the original LP241 plate (I had removed the three L wires), The Hive plate and the mess of wiring in the junction box

 

[CountryFan]

Ok, first set the existing mechanical thermostat to maximum and see if this operates it independently. If this does, then you have found your issue, I suspect the link is wrong. If this doesn’t work, then I think it’s the hot water off connection could be wrong.

 

[LordWhiteley]

Ok so when I fitted the hive control unit, the original mechanical thermostat was still connected and I set it to 30degC (ie maximum). This when I realized that the CH would only come on when the HW was set to on. I then shorted out the thermostat at the terminal box without making any difference.

I might refit the LP241 and with the old thermostat shorted, should give HW and CH continuously when set to on.

I could try swapping the 3-way valve

Failing all that I will try and find a complete circuit for the system ie control box, pump, 3-way valve and thermostat and trace all the wiring back to the terminal box labelling each wire and ensuring that they go to the correct position.

 

[CountryFan]

Did they work independently with the LP241?

 

[LordWhiteley]

I'm fairly sure everything was working fine before swapping the LP241 control unit to the Hive one. And I took the photo of the terminal connector before I took the other wires off, so I know that the wiring hasn't changed. I've recovered the original LP241 so I might put that back in place of the Hive and see how it functions. With the old thermostat removed and (shorted out in the terminal box) this will just mean that the CH will remain on continuously when turned on. If everything works fine by replacing the LP241 then it's an issue with the Hive unit. If it still isn't working as expected then maybe the micro switch on the 3-way valve is faulty and not firing up the boiler when CH is enabled.