Hive to Main Eco Compact Combi Boiler

[takuhii]

Hi,
I am trying to replace my current Center Wireless Receiver and Thermostat with a Hive Mini Wireless Receiver and Thermostat. however I have come unstuck with the wiring... The Center receiver in question is connected to a Main Eco Compact Combi Boiler, with the current setup like this...

N = Neutral
L(1) = Live
L(2) = Loop (start)

A = Loop (finish)
B = Earth

On the Hive I have;

N = Neutral
L = Live
1 = Switched Live (Start of what should be the loop)
2 =
3 = Switched Live (End of what should be the loop)
4 =

Earth to the tether...

1 and 3 don't exist currently

How do I make this work for Hive, as from what I have read so far, that loop between L(2) and A is no longer required(?) and I am supposed to run two new wires to points 1 and 3 on the Hive?

Has anyone seen this setup before and how do I make it work please? I'm not a novice to electrics, but this is a new one on me...

 

[ericmark]

Some one has been very naughty, that green/yellow wire is not earth, but supply to turn on boiler, as you have it seems worked out, you need new cables to comply with regulations, with Hive single channel you still need the loop, L to one, and the green/yellow would go to 3, with duel channel no loop and green/yellow will go to 4, but next EICR it will likely be condemned, so really needs a new four core cable or 3 core and earth cable.

 

[ianmcd]

you dont have an earth and you dont require one, never go by wiring colours in a heating system

 

[ericmark]

and you dont require one

Since 1966 a circuit protective conductor shall be run to and terminated at each point in wiring and at each accessory except a lampholder having no exposed-conductive-parts and suspended from such a point. So it is required by the regulations unless it is portable equipment when class II is permitted.

Also the bi-colour combination green-and-yellow shall be used exclusively for identification of a protective conductor and this combination shall not be used for any, other purpose.

Yes it will work without the protective conductor, but that is not the same as saying you don't require on.

 

[takuhii]

you dont have an earth and you dont require one, never go by wiring colours in a heating system

Thank you for bringing that to my attention, obviously I can't see the other end of this cable, but I appreciate the information there my friend

 

[takuhii]

Some one has been very naughty, that green/yellow wire is not earth, but supply to turn on boiler, as you have it seems worked out, you need new cables to comply with regulations, with Hive single channel you still need the loop, L to one, and the green/yellow would go to 3, with duel channel no loop and green/yellow will go to 4, but next EICR it will likely be condemned, so really needs a new four core cable or 3 core and earth cable.

I can definitely loop from L to 1? I've read a few things (other makes of boiler) that this can fry the PCB, but I can confirm this is a single channel receiver (will only turn the heating on and off...

 

[denso13]

I can definitely loop from L to 1

Yes, but using the earth cable marked green/yellow for live connections is wrong. There should be a separate earth.

 

[ericmark]

There are basic four methods to connect a thermostat to a boiler.
1) The thermostat turns on a motorised valve, and the valve turns on the boiler, there was and odd 24 volt valve, but very rare now, in the main 230 volt (low voltage) control.
2) The thermostat connects direct to boiler with 230 volt (low voltage).
It seems from the picture of old thermostat yours uses one of the above. Either way 230 volt.
3) It uses volt free contacts in the thermostat, and uses extra low voltage, in the main around 24 volt, and this means if supplied with power as well you need at least 5 wires, but in the main one uses 2 cables, one for low voltage to power the thermostat and one for extra low voltage, as the capacitive and inductive linking inside the cable can cause problems when combined.
4) A variable voltage normally around 0 - 40 volt, which turns boiler up/down rather than on/off, for example OpenTherm.

Clearly with 3 and 4 you don't want mains connecting to the thermostat wires, but the picture you show clearly says 240 volt, which was the pre-harmonisation voltage, now we call it 230 volt, although in real terms no change. So it is clear the system did use a 230 volt control.

Be careful with the name "Low Voltage" most of the world this means 50 - 1000 volt when using AC, except USA, they seem to call what we call extra low voltage (0 - 50 volt AC) low voltage. They don't use the international standards organisation definitions.

 

[RandomGrinch]

Since 1966 a circuit protective conductor shall be run to and terminated at each point in wiring and at each accessory except a lampholder having no exposed-conductive-parts and suspended from such a point.

Some have argued that this requirement ends at the FCU, from which the boiler and stat will enevitably be supplied.
(Perhaps anoher debate for the electrical forum! )
A simple compromise, for the moment, cover the green/yellow wire with some brown sleeving.

 

[takuhii]

Some one has been very naughty, that green/yellow wire is not earth, but supply to turn on boiler, as you have it seems worked out, you need new cables to comply with regulations, with Hive single channel you still need the loop, L to one, and the green/yellow would go to 3, with duel channel no loop and green/yellow will go to 4, but next EICR it will likely be condemned, so really needs a new four core cable or 3 core and earth cable.

Have connected as per ericmark's instructions. And all is running fine... I will need to replace the cable eventually, but will probably wait for it to warm up a bit so I can take my time

 

[ericmark]

Good idea, winter is not the time to experiment.