I have a Honeywell MagicStat CT3200 Programmable Thermostat that I installed a couple of years ago on my 20+ year old Trane HVAC system (which has never given me a lick of trouble, by the way). Recently, though, I've caught my a/c shutting off before the set temperature has been reached. For example, weekdays at 2:00PM the thermostat is set to knock the temp back to 74 (from 78). Today when I came home at 2:30, the a/c was running but the thermometer read 79. A short time later, the a/c shut off with the temp reading 78 (even though it was supposed to cool to 74). Later it came back on and eventually cooled the house to 74. So the a/c unit appears to be working (it was just checked last summer). I've replaced the batteries in the thermostat and reset it. Could it be defective?
Any advice would be much appreciated.
(Sweating in) Virginia Beach, VA
in a 20 year old system the liklyhood that you 2 year old thermostat has a problem is low most likly the compressor is kicking off on thermal overload causing the intermitint problem it might be time to start planing for the replacment