"DrMega" writes:

- I'm totally lost with voltage compatability issues - how do I
determine this?

Me, I'd take the old thermostat out, carefully label the wires I
disconnected so I know exactly where they went on the old thermostat
(which may be helpful in transferring them to the new stat), and bring
the thermostat with me to a store that had some help that knew
something.

If you want to kill some breakers, the ones that control the boiler
and fan are the ones to go after. Typically though stats run off low
voltage wiring and there's not much reason to worry.

--
Todd H.
http://www.toddh.net/