I am changing from an old Honeywell Dial thermostat to a new digital Hunter. I only have 4 wires (green, white, blue, and red). It appears that green goes with G, red with R, white with W. The other setting on the new thermo is Y. Does the blue hook into that?

With 4 wires, generally you can touch any wire to anything for a short period and nothing bad happens. Y is most likely blue.

If you short these terminals, the following happens.
R to Y; outside unit turns on; no inside fan
R to W; Heater fan and heat sometime later
R to G; Fan turns on

The only caveot is, you can't connect R to Y unless the outside unit is off for about 3-4 minutes. You may pop the AC fuse.


The type of stat matters; e.g. An electric furnace (Resitance element) requires a different configuration than Fossil fuel.

We do recommend that you take the Hunter stat back.