I have a replacement programmer which is approx 8 months old. This was installed when my old mechanical clock packed in. Basically it is a Danfoss TS715 single channel time switch. (Programmer).
When the timer was installed by Homeserve a metal box which contains all the wiring and electronics to convert the unit was first mounted in place of the mechanical timer and wired to the mains and pump etc. The Danfoss programmer was then mounted on the box and connected with three wires. It worked a treat an much better than the old mechanical one.
This conversion cost me £90 (parts only)
On Thursday I had a new combi boiler fitted and have salvaged both the programmer and the metal box, unfortunately the plumber disconnected the programmer from the metal box and cut the the cables leading to the pump mains etc.. I dare say any leccy or plumber worth their salt will know how to wire this unit up.
I have also salvaged the rest of the boiler ('Elite 50' minus the pump and case- everything was in perfect working order. To be honest the only reason I changed the unit was because of additional radiators which would have put too much strain on the old unit.
So if you or anyone else interested, make me an offer.
Stuart
November 2008