"L Reid" wrote in message
k...
"xena" wrote in message
...
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



Ok, in addition to the green/yellow, is there a separate earth?
Alternatively, is the green / yellow fully sleeved, or is it the earth of
twin & earth (i.e. a bare wire with a yellow sleeve over a small part of
it)? Also, do you know what model of programmer/timer that you have? It
may
be that you might have to take the casing off of that to confirm the
wiring.



No, there is no separate earth.

The cable is bog standard 3-core flex, not twin and earth, so fully sleeved.

The programmer is a Horstmann Channel Plus H37.

Thoughts at the moment are that the brown wire is in the right place (live).
The green/yellow is the neutral
The blue is the switched live (call for heat)

Does anyone know of any multimeter checks I can do to verify this?

And thank you everyone *so* much for your help!! It's the first time I've
posted on here, and the response has been amazing )

Thanks you all
xena