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Make Redundant Thermostat Wiring Safe After Installing Hive

Postby charliegriff » Sat Jun 30, 2018 6:08 pm


I'm replacing my current thermostat with a Hive thermostat. The current thermostat wiring runs from the programmer to a thermostat in the front room.

Most of it is straight forward, as you just swap the wires over from the old thermostat to the Hive, however, because the Hive is wireless, I no longer need the wires that run from the programmer to the old thermostat sensor in the front room.

Removing the wires from the wall altogether is not an option, so is it possible to just attach a Wago Block to each end of the wires that are coming out of the walls and push them back into the wall cavity? Will that be safe enough?

In the front room there's a live and neutral wire. At the programmer end, there's live, neutral and earth. Will it be OK to just put all the ends into a Wago block and leave them?

Thermostat.png (6.75 KiB) Viewed 3611 times

Thanks for any help.
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Postby Mr White » Sun Jul 01, 2018 8:33 pm

If you disconnect both ends the cable will be safe. Wagos will be of no harm.
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Postby ericmark » Tue Jul 03, 2018 8:39 am

If the wires remain live, then something to identify that there is wiring is required, a blank is OK plastering over is not.

To disconnect wires it often needs to be done at the control centre not the programmer, this means identifying wires, motorised valves have standard colours however most of the wiring could have any core colour.

Much depends on what system is installed, W, S, Y etc. I wish now the wires to my thermostat had not been removed.

I thought I knew about central heating until returned to mothers house, not the wiring, it is how to control, I am likely to worst guy to give advice, intended to install nest, however found my boiler (bosch) needs to use Bosch thermostats to modulate the boiler, nest needs a opentherm enabled boiler, and hive can't modulate the boiler, it can only turn it off/On.

So in the future you may want a proper control system, and you may need those wires.

Just to explain modulating, it means the boiler flame goes up and down to suit demand, this is in the main done using thermostat radiator valves (TRV) and the boiler monitors return temperature of the water, great mid winter, but as summer arrives we want to stop boiler cycling, best option is for TRV to connect to a central thermostat which in turn controls boiler so boiler no longer uses return water temperature, EvoHome is a good example.

However we look for cheaper methods, Nest can follow Mihome electronic TRV so can do something simular, but in the main we use cheap wall thermostats to turn heating off in Summer.

We are told the thermostat should be in a naturally cold room, with no outside doors, and no TRV in that room, however in my house there is no such room, so the compromise in my case is duel thermostats, also room with wall thermostat (The hall) does have a TRV to reheat room quicker once door is opened.

It is a compromise control v cost, the only advantage of hive to any other programmable thermostat is ability to control with phone, however my eTRV can also be controlled with geofencing on a smart phone, but in real terms the fabric of the building, and amount of water in radiators store too much heat, so response time is too slow.

So first question is if front room right place for a thermostat? In the main living rooms are kept too warm for thermostat to work, if you have room at 20°C then in Summer it will be too warm in morning, you want whole heating off at 18°C so room will not be too hot latter, so store room, or in my case hall, living room temperature controlled by TRV which modulate boiler, thermostat only turns off heating when every room satisfied to stop cycling.

As each TRV turns down there reaches a point where the boiler can't turn down any more, at that point it starts to cycle, off/On, when it turns on again it may monitor after a delay return water, if still hot it increases off time, other wise it shortens off time, this is called anti cycle software, however it can never turn boiler completely off, it needs to pump water around the system to see if it's needed, the thermostat on the wall is set to stop this cycling. So its location is selected to turn off whole system in summer, not to control room temperature, the TRV does that.

I have two electronic TRV heads and temperature control is spot on.
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