Replacing LP241 for Drayton Wiser

[SBBrighton]

Hi. My Honeywell CM927 has finally given up so I’ve been researching smart heating controllers to replace it. I think I’ve settled on the Drayton Wiser two channel kit which is currently £99 at Screwfix.

Currently I have a Lifestyle LP241 which controls the water heating on a twice a day timer and for the central heating there’s the (now dead) CM927 linked to a Honeywell R6660D connected to the LP241.

Am I right in thinking that I can get rid of all that old kit and simply replace the LP241 directly with the Wiser which will control both water heating and central heating? Are the backplates universal so that I can literally just mount the new Wiser receiver where the LP241 currently is or will it need replacing / rewiring? If it needs rewiring can you advise what’s required please.

I’ve attached some photos of the wiring in the LP241, R6660D, and junction box. On the junction box the grey on the top is mains, the clean white goes to the LP241 and the dirty white goes to an isolator switch. On the bottom the black goes to a Drayton MA1 actuator and the white goes to a Drayton HTS3 cylinder thermostat.

Many thanks
Steve

 

[RandomGrinch]

Am I right in thinking that I can get rid of all that old kit and simply replace the LP241 directly with the Wiser which will control both water heating and central heating?

Yes.

Are the backplates universal so that I can literally just mount the new Wiser receiver where the LP241 currently is or will it need replacing / rewiring?

The backplate is theoretically 'universal', there's no harm trying it for fit.

There will however need to be a slight change to the wiring.
Currently a grey wire comes out of terminal 4 on the LP241 and goes to the R6660D. A Black wire comes back from the R6660D and joins with another black wire in the separate terminal block.
To remove the R6660D from the picture, take out the grey wire from terminal 4, and replace it with the other black wire, currently in the separate terminal block.
The rest of the R6660D wiring can then be removed.

You shouldn't need to touch anything in the wiring centre.

 

[SBBrighton]

Brilliant. Thanks RandomGrinch. That sounds remarkably straightforward. Will pick up the unit from Screwfix tomorrow hopefully.

 

[Rodders53]

Errrmmm....

That wiring in backplate is odd.
T1 has green/yellow wire (earth??).

T1 on Drayton will be Live when HW is OFF so may blow the fuse when energised!

Remove it and place into a choc block (or use the Wiser backplate's earth terminal.

T3 is HW on
T4 is CH on and needs the correct black wire in choc block relocating (and gives you a block for the earth).

 

[Stuckinarut]

Errrmmm....

That wiring in backplate is odd.
T1 has green/yellow wire (earth??).

T1 on Drayton will be Live when HW is OFF so may blow the fuse when energised!

Remove it and place into a choc block (or use the Wiser backplate's earth terminal.

T3 is HW on
T4 is CH on and needs the correct black wire in choc block relocating (and gives you a block for the earth).

Nope. It's been incorrectly used as a switch live/hot water off, it's not an earth/cpc

 

[RandomGrinch]

T1 has green/yellow wire (earth??).

T1 on Drayton will be Live when HW is OFF so may blow the fuse when energised!

Yes, I had checked the wiring centre, and it is a Y plan connection to the grey wire of the 3-port valve.
Yes, the green/yellow wire shouldn't really be used as a switched live, although it wasn't explicitly banned until recently.
Yes, it should be oversleeved in brown.
And no, I didn't mention it, as the OP only had to move one wire to allow the Wiser to operate correctly; I didn't really see that as a modification to the circuit that would require updating it to the current regs.

Edited for clarity.

 

[SBBrighton]

Yes, I had checked the wiring centre, and it is a Y plan connection to the grey wire of the 3-port valve.
Yes, the green/yellow wire shouldn't really be used as a switched live, although it wasn't explicitly banned until recently.
Yes, it should be oversleeved in brown.
And no, I didn't mention it, as the OP only had to move one wire to allow the Wiser to operate correctly; I didn't really see that as a modification to the circuit that would require updating it to the current regs.

Edited for clarity.

So I’m still good with the original plan aren’t I? Should I oversleeve the yellow/green with brown whilst I’m in there to avoid any future confusion or is it not worth it? I think it’s in terminal 8 in the wiring centre isn’t it?

 

[Stuckinarut]

So I’m still good with the original plan aren’t I? Should I oversleeve the yellow/green with brown whilst I’m in there to avoid any future confusion or is it not worth it? I think it’s in terminal 8 in the wiring centre isn’t it?

It wouldn’t do any harm to sleeve it or put brown insulation tape on it.

 

[RandomGrinch]

So I’m still good with the original plan aren’t I? Should I oversleeve the yellow/green with brown whilst I’m in there to avoid any future confusion or is it not worth it? I think it’s in terminal 8 in the wiring centre isn’t it?

Yes - all good.
And as @stucksays, Brown tape or oversleeving would be ideal, on both ends of the green/yellow wire.
Yes, it does connect into terminal 8 of the wiring centre.