Horstmann Centaur C21 To British Gas Hive

[Jonnylogan85]

Hi!

Trying to replace Horstmann Centaur C21 to British Gas Hive. The wiring is confusing me a little... The existing wiring as attached picture. The control unit is connected to a Horstmann HRT3 thermostat.

Any suggestions as to how to wire up, greatly appreciated....

 

[Gas2Air]

No need to re-wire anything, maybe use the new HIVE backplate for ease, but the HIVE receiver should fit on that original one you have installed, you have 2 neutrals, 1 live, the yellow is hot water on and the red is heating on, make sure it's an S-Plan as I suspect, 2 valves in airing cupboard, I have seen wiring like this on a Y-plan with no hot water off. Link the room thermostat out in the junction box, heating on wire the red to brown from heating valve, or you could be naughty and link it out behind the room stat, making sure any unused terminals are blocked off.