Replacing Potterton EP2002 with Tado

[samjhw]

Hi all, first time post on here.

I currently have a Y plan heating system running off a Potterton EP2002 controller, which I am wanting to install a Tado Starter Kit V3+ on.

I have got as far to install the internet bridge and decommissioned the wired wall thermostat and replaced it with the Tado.

Now comes the tricky part:
The EP2002 has the back panel which seems to act as the wiring centre and I'm struggling to get my head round what's going on in there!

I imagine I will need to install a wiring centre/choc blocks to help consolidate the earths and neutrals, then run a L, N, CHNO, HWNO, HWNC out to the Tado receiver/programmer mounted adjacent?

N.B. wires coming in, left to right, are motorised valve (black), boiler, HW stat, the furthest right is puzzling me a little as this is from the 3A spur, but is a 6 core. I can't identify any wires coming in separately from the CH wall stat (now decommissioned). Is this likely to be coming in on the 6 core and I'm missing a junction box somewhere?

 

[CBW]

The 3 port motorised valve shouldn’t be wired directly to the programmer, so best doing what you mentioned and place a makeshift wiring center next to it. I can’t see 6 cores in the furthest right one.

 

[ericmark]

Over the years central heating tends to get upgraded but often old controls are used.

Start by looking at boiler, is it an old oil non modulating these tend to last 25 years so not changed that often, gas boilers don't last as long, and many modern boilers can use a modulating thermostat, again depends on age, early boilers were controlled by return water only, latter ones can use modulating thermostats, some use Opentherm but some need thermostats specially for that boiler.

The old wiring may be OK, but could also be outdated, also it may not have been wired correctly to start with. Selecting DHW off uses diffrent wiring and contacts to turning off DHW as it is at required heat. Seen missing wires many times.

Also seen missing earth wires, and green/yellow wires used for live.

In the main we identify wires using the motorised valve colours, as the valve normally comes pre wired we have no idea what colours mean with any other wires.