[vornado]

It is a RobertShaw 9600-

Setting is for MANUAL

Temperature in house is 76 degrees

Manual setting for a/c to come on is 79 degrees.

A/C comes on. A/C installer told us thermostat unit is BAD. Sold us a replacement.

Same issue.

Per RobertShaw help desk " this is a wiring issue"

Question: What wires could be involved?

Thanks

Montaques

[esquire1]

You need to check all the low voltage wires from the stat to the airhandler. If the unit is not shutting off, sounds like the wires from R (normally red) and Y (normally yellow) are making contact