replacing room thermostat

[meatpie]

Hi if anyone can help.I want to replace the old ACL room thermostat i have.When i opened it up it is wired as follows

1.... red wire connected
2.... black wire connected
Earth..... earth wire connected
4.... No wire connected

I wanted to replace but it is wired up with only twin and earth.

Any suggestions?

[plumbbob]

I wanted to replace but it is wired up with only twin and earth.

Any suggestions?

I am not sure why you think there is a problem?? This is the industry's modern standard and almost every voltage free digital thermostat will fit.

[meatpie]

Cheers
its just on instruction it has the following for wiring

H NO COM NC
E ..............| |...................L
A ..........................................N
T
E
R

So where would the red black and earth go
NO=
COM=
NC=

Thanks

[plumbbob]

The earth obviously goes to the special earth location or is cut off if no terminal is available.

The red and black are connected to the Common and NC respectively. NC (Normally Closed) and NO (Normally open) refer simply to the relay contacts being either open or closed.