RH is the power in for the heat side (RC is power in for the cool side, but
you don't need it with a heat-only system)
W is the "call for heat" terminal
Y is the A/C compressor terminal, you shouldn't be using it.
G is the "blower on" terminal.

Assuming your furnace is wired with standard colors, I'd try Red to 'R',
white to 'W' and green to 'G'

-Tim

"AB" wrote in message
ps.com...
I read through tons of the posts on this group, but none addressed my
specific issue. Hopefully, someone can help me figure out how to
install my two new
digital thermometers. (Lux ATX1500's) Anyway, the problem stems from
the fact that I am replacing very old mercury Flair thermostat that
has three wires connected to numbers, not letters. Therefore, I don't
know how they correspond to the new thermostat. The Flair's are wired
as follows:
White - #6
Red - #5
Green - #4

I connected the white to RH, which came pre-jumpered to RC on the Lux.
Green went to W and Red to Y. While the heat came on, it went up to 80
degrees and didn't come down as I had timed it to. I'm obviously
screwing something up.(I've tried several other combinations with the
same result) It's a heating only system, and I obviously
don't have the cooling mechanism wired correctly. (and maybe more) The
documentation doesn't help, and I can't find a thing on the Internet
on Flair thermostats. Any help would be greatly appreciated. Thanks!
- Adam