Thermostat replacement

[chnightmare]

Am trying to replace my room stat but not sure of wiring - need some help.
New stat is honeywell T6620 - not sure what old type is - honeywell of some kind, original has 3 wires - an earth and two additional wires, red and blue. New stat has 3 terminals marked A B and C. Any ideas how to connect ?

 

[Taylortwocities]

Have a look here: http://www.screwfix.com/talk/thread.jspa?forumID=25&threadID=10231&messageID=96802

 

[chnightmare]

can you offer any guidance as to meaning of A B and C or is it random nomenclature ?

 

[Steve3948]

Am trying to replace my room stat but not sure of wiring - need some help.
New stat is honeywell T6620 - not sure what old type is - honeywell of some kind, original has 3 wires - an earth and two additional wires, red and blue. New stat has 3 terminals marked A B and C. Any ideas how to connect ?

If you have a Red and Blue, are you sure you do not have a Yellow.
Your Earth should be bare with a green or green and yellow sleeve over it.

However if you do have Red and Blue, then A=Live In, and B=Switched Live Out.