Replacing a HW/CH Controller Box

[KennyPowers]

Hi All,

I have a Potterton CH/HW system, and are looking at the possibility of replacing the controller box as the switches are getting delicate/making bad contact, and overall the plastic has gone yellow/brittle.

My question is, can I replace it with any controller? (IE are they all compatible/universal), or do I have to find a specific Potterton one that is compatible. I would have thought the control volts going out, and thermostat volts coming in are the same across all systems?

Thanks,
KP.

 

[Gasguru]

The backplate is unique and you'll often find its crammed with a ton of wiring...so replacement with most programmers can be complicated.

However AFAIK the current Potterton EP2 programmer should fit onto the existing backplate...check first.

 

[KennyPowers]

Thanks Gasguru,

After a bit of Googling, I found this blog that talks about replacing the older frontplates with the newer EP2 like you said.

He did say that in reality the backplate should be changed too, due to the ton of wiring in it.

https://www.electriciansblog.co.uk/2014/03/potterton-ep2002-ep2-central-heating-control-programmer/

 

[Gasguru]

It was a dumb idea from Potterton to turn the backplate into a wiring centre but it was probably done to cut costs for the new build market.

 

[stem]

Any dual channel programmer can be used to replace the Potterton EP range.

Electrically speaking a programmer contains two internal on and off switches, one for the heating and one for the hot water, and that's it, that's all they do, so you don't need to replace it with another Potterton programmer. There are a lot of threads on here where people have replaced them with Nest or Hive units.

However, whilst you won't have to run new cables to do this, a certain amount of re configuring is required, and you need a fairly high level of electrical competency to do it.

As Gasguru siad, if you don't want to, or can't modify the wiring then the EP is still available, I replaced one last month. However whilst it would have fitted onto the original backplate, I always fit the new one anyway, so that the backplate and programmer are both new together.

 

[KennyPowers]

I think for simplicity I'll just go with the Potterton EP2, though I might replace the backplate with the new one like you said. (It's old yellow and the plastic is probably crumbly)

Just need to make sure I make a note of where all the wires went, and label them up. Will probably be a nightmare figuring out what they are from scratch.

Dunno what a Hive or Nest system are, but assuming they are like those smart meters that keep being pushed on everyone. Linked to, and conteolled via the internet?

 

[stem]

Yes, they are programmable thermostats you can control via an app remotely and they look smart if you are into that sort of thing. They are quite fashionable at the moment, so a lot of people have been installing them.

I've installed quite a few and assisted many on here to install them, but I don't have either myself as they don't offer me any tangible advantages, so I wasn't promoting them, just using them as an example to show that other programmers can replace an EP.

Nothing to do with smart meters BTW, they are something else entirely......and I don't have one of them either......

 

[KennyPowers]

You've piqued my interest with these ''smart" thermostats.

If I were to fit say the Hive controller (instead of the Potterton EP), in a nutshell it would use the existing wiring already present behind the Potterton EP2002 controller, and 'bypassing' the Potterton thermostat. Is that all is required?

I might give it a go, as I like the look of the Hive thermostat over the Potterton controller. Can I skip the wireless router bit, and I'm not bothered about controlling it over the internet with my phone?

 

[stem]

The smart thermostat could replace the existing programmer using the wires currently present, but the old thermostat has to be decommissioned by removing it and adding a link where the live switching wires have been removed from to complete the circuit.

I've not installed any without having a Wifi connection, and don't think you actually can because the set up is done through it.

 

[KennyPowers]

Maybe once it is intially setup over wi-fi, the router element can be binned? Otherwise you would be stuck if your internet went down.

Not sure I would like having household items permanently connected to the internet like that, with all the stuff in the news about security leaks, hackers, burglers seeing when you not at home etc.

 

[KennyPowers]

Going to bin the Hive idea, sounds like extra complications I wouldn't really use/need.

Question - would the Drayton LP722 be compatible with the existing Potterton EP2002? Looking at the manual, it would appear so to me: https://www.draytoncontrols.co.uk/sites/default/files/LP722 (U.&I. Guide)_1.pdf

I prefer the Drayton design over the newer Potterton EP2 design, as it looks simpler to use, and has no delicate sliders!

Cheers,
KP.

 

[stem]

There isn't anything that will be a direct replacement for the EP without making any wiring modifications, except for another EP. However the Drayton is about as close as you will get.

The Drayton terminals are:

And the EP, is very similar:

You will see they are virtually the same, with the exception of terminal 5 of the EP which is missing from the Drayton. However if you look carefully you will see that this connection is made internally inside the Drayton, so it doesn't have a terminal 5.

The difficult bit, is that the EP also includes a set of terminals that have no function with regard to the programmer, but are simply provided as a junction / terminal box. The terminals are labeled A,B,C,D and provision will need to be made to terminate the wires in them elsewhere. These terminals are shown below. However, they are not always used. It depends how the original installer decided to make the connections.

 

[KennyPowers]

I don't mind changing the backplate, and re-wiring into it.

For the A,B,C,D wires, if they are not used & no longer catered for in the new backplate, I was thinking just shove them in choc-bloc, or maybe crimp together, and tuck back into wall?

Cheers,
KP.

 

[stem]

Usually there is a metal back box sunk in the wall, so I do exactly that. Make sure the metal back box has an earth connection to it. Usually it's there, but not always.

The wires need to remain connected as they are as they form part of the heating circuitry. So, the wires in A need to be kept connected together. And the wires in B need to remain connected together etc....

I forgot to mention earlier that there is also a neutral strip to the left and an earth strip to the right, the same applies to the wires in each of them.

 

[KennyPowers]

Got a Drayton LP722 off Amazon in the end, thought I might tackle on one of my Christmas days off.

Took off the old Potterton EP2002 faceplate, and was greeted by the below picture. Not quite what I thought it would be.

There appears to be a floating wire (maybe it came out of terminal A?) and also a loop wire from L to 5. There is no terminal 5 on the Drayton, so do I just ignore this one? Also nothing in the left-hand neutral strip.

The HW/CH still works alright, so it would seem the floating wire wasn't essential.