Not sure if bump required...

I might be way behind the times here but I would would have thought putting a smart thermostat on an electric towel rail is a complete waste of money. What are you wanting to achieve that the normal thermostat can't do?

It's for a holiday home, so purpose is to able to switch off or on (or confirm switched off or on) when we are a few hundred miles away.

I'm no electrician but couldn't you achieve the same by replacing the isolator switch with a smart switch?

Not really - as you don't have confirmation that the "dumb" thermostat will be set to a particular temperature. We're wanting it set low in the winter, for frost protection.

So I'm guessing there's no helpful answers on wiring this in, just the usual STW "you're asking the wrong question" replies? 🙂

So I’m guessing there’s no helpful answers on wiring this in, just the usual STW “you’re asking the wrong question” replies?

That'll encourage people to help you... 🙃

Thats an odd one

I read it as 1 being normally closed, 2 normally open, 3 neutral pass through and 4 live pass through.

So wiring your heater across 2 and 3 seems wrong.

Is it an electric heater? If so are you sure 3A is enough? I note your old one has 30A load capacity.......

Have you tried asking a qualified installer? I think you need to put this one in the bin.

The text seems to suggest that 3 is neutral pass through and 2 is switched live.
The diagram is pants.

I’d wire up your feed L/N to 3 & 4 and test 2 with a test screwdriver or meter. See if you get a live (with it activated obviously!)

3A is plenty as the element is probably only 150 to 300w

As for the intention, definitely a good idea.
I’ve done the same for our holiday home in Austria so I can switch the towel rail on to a timed/temp setting when guests arrive. Works great.

I'll also second (third?) your idea - I'm doing the same at our holiday place.

I've already swapped the electric underfloor heating thermostat with a smart one from Warmup and I'm just about to change the on/off switch for the towel rail with an underfloor heating timer/thermostat so I can at least automatically switch it off during the night.

Thanks for tips. My combination of nonexistent electrical skills plus the useless docs from this product mean I haven’t been able to get it to work. Returning it for another smart thermostat that seems to get good reviews, and should hopefully be easier to wire in. In fact, @sharkbait - I’m also going for an underfloor heating thermostat, which from what I can tell online should also work for a towel rail.

4 - L is live supply

3 - N is neutral for the controller so you can also use it as a common N terminal for the heater if the wires will fit in the terminal. You may need a 3 way wago terminal if they won't.

2 - is Live to the heater normally open relay terminal

Earth will need dealing with separately.

is there a control wire from an external temperature probe somewhere, or does the thermostat itself measure temperature (i.e. the ambient temp of the room?) Either way, you can almost certainly do the job for under £20 with a Shelly WiFi smart relay - I'm a big fan of these devices and have loads of them in my house!

So wiring your heater across 2 and 3 seems wrong.

Incoming L in 4.
Incoming N in 3.
Towel rail N in 3.
Towel rail L in 2.

Seems right to me. The earth from the towel rail can be terminated in the metal back box with the incoming T+E, of if a plastic box in a Wago block or similar. Choc blocks are frowned upon now because they can become loose over time.

Terminal 1 should be left empty.

You need to ask yourself whether what you're doing is really appropriate. You freely admit that you have no idea what you're doing but want to install something that gets hot in an unattended building.