Replacing heating and hot water programmer

ninjabennett

I have an oldish heating and hot water programmer that I'd like to replace with a smart one. This is used to control an old back boiler system. Could I just purchase any smart programmer or are they all for more modern boiler systems such as combi boilers? Thanks.

grumbler

They are different.

I recently replaced mine with Honeywell T6R, and had to change slightly the connections near the hot water cylinder where the wires from the fixed room thermostat came to.

Some other smart controller seems to be a direct replacement - https://forums.moneysavingexpert.com/discussion/6147237/ch-replacing-timer-with-smart-switch#latest

ninjabennett

Thanks for your response. I didn't see the other thread. I'll do some more research and see what direct replacements there are.

missile

Hi, I replaced my old controller with Hive. The cost included installation. 

FreeBear

ninjabennett said: I'll do some more research and see what direct replacements there are.

I have an old Baxi back boiler here. Switched to a "smart" control system last year that allows for control over times and temperature on both hot water & central heating. It means I can have different temperatures in the evening & weekends. But the system is complex and requires some knowledge of computers and how to connect each part of the system together. If you are tech savvy, have a look at Home Assistant (other systems available).

For a simple "plug in & go" that doesn't require too much work, the Drayton Wise may be suitable.

ninjabennett

Ok. So I've decided to take a look at the wiring to see how to rewire to another smart programmer. The current wiring doesn't seem right to me. I've attached the images.
The live and neutral look ok but then I have an earth wire going into (1) and signal wires going to (3) and (4). There is no wire going (2).
Does this look right to anyone because it doesn't for me?
I'm guessing the earth should be moved to the earth terminal which leaves nothing in (1) and (2).
I do get the heating coming on when I only put the hot water on but I thought it was the 3 way valve not working.
If anyone could look at this and confirm that the wiring is wrong then I might have to replace it all with the correct wiring. Thanks.

grumbler

It's not earth - ignore the colour. The controller doesn't need it. It's just a flexible 5-core cable used to connect other devices to the controller. Most likely you'll find the other end of this cable in a junction box near your hot water cylinder.

I used this guide to decipher the original wiring - https://www.flameport.com/electric/central_heating/heating_wiring_Y_plan.cs4

And this did take me some time.

ninjabennett

Thanks for your help. I watched the video and it all made perfect sense!

FreeBear

grumbler said: It's not earth - ignore the colour. The controller doesn't need it. It's just a flexible 5-core cable used to connect other devices to the controller.

But.... Yellow/Green earth wire should never be used for anything else other than earthing. Putting a bit of (say red) sleeving over the offending wire at either end would highlight that it is likely at mains potential - Changing the colour of a wire, particularly yell/green, is something that should never be done.

Put a notice up on the junction box stating that the Yellow/Green wire is likely to be at mains potential - Do this at both ends..

southcoastrgi

It's wired correctly you don't need anything in 2, they have used multi core, yes the gy could do with a bit of red sleeving but sometimes needs must, it's double insulated so doesn't need an earth