For my air conditioning, my programmable Honeywell chronotherm III will not work in Auto mode. It only works if I put it into Auto Mode, and then only for a little while before turning off. The AC unit is new, the breaker has been checked.

Im confused. You say it won't work in auto mode, then you say it only works when you put it in auto mode?

My mistake, the thermostat only works in "fan on" mode"

Since my last post I have replaced both of my thermostats in the house. One of them works fine, the other does not. The one that does not replaced the thermostat that worked on in "

Since my last post I have replaced both of my thermostats in the house. One of them works fine, the other does not. The one that does not replaced the thermostat that worked on in " mode.

The new problem is that now this new thermostat only activates the heater - even though it is set to cool. So now I have to either shut off the heater for this zone or I have to deactivate this new thermostat. Current situation is that I have the thermostat deactivated - only one zone in the house is cooling, the one with the thermostat that works.

I have checked the wiring on both thermostats several times - they are wired correctly according to the wiring instructions that came with the new honeywell thermostats.

Is this two zones with one central unit? If so you may need to read the instructions on the actuall zone control box to get this all figured out. Some zone control boxes require special wiring and stats to operate correctly. This can get a bit confusing if you aren't used to dealing with a pile of wires. Find the wiring diagram/install insructions for the zone control and see if it says anything about special wiring or stats. If you can find a phone number for tech support it would be the best way to go in figuring this all out.

Good luck, and please let me know what you find.

Lee.