Hi there

I would really appreciate help with this.

The thermostat for the downstairs heating in our house has never worked, so
I took a look at it today. There are 3 wires going to it: green/yellow,
blue and brown.

The thermostat is a Drayton RTS1, which has 4 terminals: Neutral, Live, 3
(Call for heat) and Earth.

Currently, the wiring goes: Brown to Live, Blue to Neutral, and Green/Yellow
to Earth.

This leaves nothing going to the 3 (Call for heat), which I guess is why the
thermostat isn't working!

I'm guessing that one of the following is the case:
1) the green/yellow wire may actually be the 3 (Call for heat)
2) the green/yellow is actually neutral, and the blue is the 3 (call for
heat)
but I need to know how to check this without fusing the system! Also this
would leave no earth - is this likely?

I've got a digi multimeter, and there's 230 Volts coming down the brown
(when checked against either the blue or the green/yellow), so that's in
right, but how do I find out how to rewire the other two?

Many thanks for any suggestions.
xena