ST-3E, Ac will not turn off unless Cool to Off

[Pittwr]

I have a standard Honeywell thermostat connect to a EWC st-3e control panel with 3 zones. System used to work fine but now when the ac is set to cool it kicks on but it will not turn off once at the selected temp is reached.
The dampers will operate and close the zones though.
I can turn the ac off by going from Cool to Off on the thermostat...
Paid a guy big bucks to fix it and he thought it was bad wiring from the thermostat to the panel. That's fine, I checked the wiring. I wasn't home of course when he was there.
Sometimes there can be a delay off several minutes before the ac will kick on...
Heating side of things has always worked fine.

Is the problem with the thermostat? EWC panel? Or going out to the air handler?

Thanks,
Bill
Sherman, Ct

[Paul Z.]

Sorry for the late reply. Give me a call, have a few questions 1-800-446-3110 X490.