Replacing a ESI ESRTP5 room thermostat with a WiFi Thermostat

[rmndr]

Hi, I have an Ideal Logic ESPI 35kW boiler and 2 heating circuits. One for the ground floor and one for the 1st and 2nd floor, like this.

Both are controlled by a wall mounted ESI ESRTP5 wall-mounted thermostat. The wiring of the thermostat looks like this.

Now, I know I could probably easily replace this with the ESTRP5WIFI version and you can get smart TRV's etc - but there are other 'generic' options out there that are a bit more price appealing and I really don't need much control authority, just lazyness to get up and down floors adjust temperatures. t confused about the wiring.

But I was a bit confused about how to wire it up. This is pretty exemplary of wiring for Thermostats I've seen on Amazon. But in all those examples there's 4 wires in total, but I have only 3?

 

[stem]

Normally the thermostats with 4 terminals have an N & L for operating power, plus 2 more terminals for switching purposes. In which in your case will still only need 3 wires, as the L will be connected to two of the four terminals.

The ESI ESRTP5 you have now has the link between L and one of the switched terminals made internally, so doesn't require an additional external connection.

This means that your existing thermostat having one side of its switch internally connected to L can only be used for heating systems using 230V for control. Some boilers use 24v so must be kept isolated from the mains supply. The 4 wire connections allow the thermostat to be used with either 230V or 24v.

 

[Deleted member 267285]

Edited.

 

[rmndr]

Thanks,

So in this example I would just run a little connection from L to 4? And where the ESI stat was on 5 I'd do the same right?

 

[stem]

Looks good to me