Heating Problems

antlyn

Was at a friends house earlier, she has been renovating it and is after getting a new heating system. She has a wood pellet boiler fitted, which is not yet commisioned. Her sparks (and apprentices!) couldn't wire up part of her heating, so she called me as I'm an Elec Eng. But I've never seen this setup before. They have a contactor wired to bring in the boiler when called for. The room stats aren't required just yet, but there are two tank stats (not for the solar!) on the new hot water tank and they said that the installer who is currently away, said that the higher stat will call the boiler when the temp in the tank drops below a certain temp, e.g 50 degrees but the lower stat will ensure the boiler keeps running until it reaches roughly 70 degrees. Am I right in thinking that the stats are in series??? The idea of this system is to keep the boiler running when the first stat comes up to temp, without having to refire the boiler. Would anyone have a wiring diagram for this. Thanks

Plombier

This is what you need to do if you can follow it.
Bottom stat normally closed.

|____[Top Stat]_______[/Bottom Stat/]___________(Relay)___|
|____[Relay]______|