circuit diagram for stat and programmer?

Have you tried the volkera website? As a rule of thumb the circuit board on most combi's will have 2x teminals that have been "linked out", this is where you connect your room stat.With the link in it is always "calling for heat".Select your stat carefully as some are electronic and require a neutral a good merchant will be able to advise you more,hope this is of help.

Lawrence
November 2007