Replacing Potterton EP2000 with hive

[SteveV1980]

All,

I've got myself into a pit of a pickle and after a bit of assistance.

Bit of a background, I've recently moved into a grade 2 listed Georgian priority with a number of foibles, but that is a story for another day.

The heating and hot water are via a boiler (old Ideal Mexico 2) and a hot water cylinder, with a pump and diverted valve, controlled via a Potterton EP2000 system, which seemed to have a mind of its own, hence the reason for looking to upgrading the system. There is no thermostat and no control for the hot water tank apart from a manual immersion heater switch.

I've bought a 2 channel hive system on the premise of the heating and hot water being separate, and removed the faceplate to be presented with an "interesting" array of wires connected in a strange way.

In the picture, the wire coming from below is the fused power, easy enough with live, earth and neutral.

My understanding, when I track back the cable on the left, is that this leads to the boiler and the one from the right goes to the pump and diverted valve.

But going on wiring diagram on the potterton backplate, this would be wrong.

On my understanding, E, N & L are self explanatory, 1 is HW off, 2 is CH off, 3 is HW on and 4 is CH on.

Looking at my wiring, HW and CH off are both not wired up, HW on goes to the boiler and CH on goes to the pump and diverter valve - have I read this right?

So when installing the Hive, would there be a way to off the CH and HW then the thermostat reads the right temperature or would it just be a lack on "on" from each of them?

Any help much appreciated.

 

[Echo the husky]

The wiring shown is appalling. I would not attempt to replace the programmer without correcting the wiring problems. There appears to be no proper earth connection and the 'earth' wires in the terminal on the left may be something other than earth.

We can only see the wiring at the programmer, so everything is guesswork. This will likely need a professional to correct, as the current wiring looks to have been installed by a builder...

 

[flameport]

I've bought a 2 channel hive system on the premise of the heating and hot water being separate,

Whether they can be operated separately depends on how the system was designed - it's not just a case of changing the controls.
If the wires go to where you say they do, it will not be possible to have separate HW and CH without altering the pipework and probably installing a new valve and cylinder thermostat.

The Hive can be set up to work with the existing system, you will just have HW only, or HW and CH together.
The 'off' terminals are not required.

 

[Echo the husky]

^ That was the thing I couldn't remember to write about!

 

[SteveV1980]

Both, thanks for the replies. I wouldn't be surprised if the previous owner installed it, as he was a retired engineer and I've already uncovered no end of bodgery in the house that he's put in.

I'm going to track back to the boiler and try and pull off a wiring diagram from the back of it, to see what the 4 wires are connected to, as well as the valve and pump.