Fitting room thermostat to old two zone system

[JonathanM]

We have an old CH system from when the house was new, just over 30 years ago.

There are two zones, one upstairs and one downstairs. I’ve been told it’s an S-Plan. Three motorised valves in total with a regular boiler and cylinder.

In each zone there are TRVs on every radiator except one.

We’ve never had a room stat.

There’s a smallish square black box on the wall next to the boiler, which the gas engineers call the control box. Everything seems to be wired through that.

I hardly ever use upstairs, so just pop the heating on for an hour occasionally. So, I don’t really need a room stat for that zone.

I’d like to know if it is possible to fit a room stat just to the downstairs. Both in a technical sense and in a legal sense. I'm just trying to save money on the install. I’ve been told that every replacement boiler now needs room stats for each zone, but I’ve decided not to replace the boiler at this time.

 

[CBW]

Yes you can have a thermostat for one zone, but if you’ve never had one then wiring will need to be altered. You could opt for the Wiser 3 channel hub (others are available), which has x2 thermostats, albeit quite expensive.

 

[ianmcd]

you have an S plan + so that is the wiring diagram you are looking for slightly different from a standard S plan