On Nov 5, 2:18 pm, wrote:

I just am looking for some sort of clue as to what might be wrong
before I call them. The house has an older heat system (elec
baseboard) so there is no huge rush.


As far as I know (caveat : I'm a software engineer, not an AC repair
guy, although I did fix my own heat pump a few years ago when the
relay that controls the reversing coil got sticky), the 24 volts that
powers the thermostat originates at a transformer in the unit. If
there is power to the transformer inside the unit, and no 24 volts at
the thermostat, then you've either got a bad transformer or an open
connection somewhere.

Without that 24 volts, you're not going to switch the main contactor
that turns everything else on.

Jerry