I had an older digital thermostat and changed it out wit a new one. It seems as if during the heat of the day I can't get it to go below 77 or 78 and I have it set it 76. The a/c blows out good cold air and the house is cool but it constantly runs and I have to kick the stat up to get it to shut off. It's a lennox not sure how old the unit is. It seems to work fine at night though. What could be causing this? My outside unit is not very well shaded could that be part of it?

I had someone come out and he said my a coil is clogged. Would this really cause this problem? The unit runs fine at night but its been 95 plus a heat index of 110 last four days

A dirty filter or a cloged coil can hurt your systems preformance. Do you change your filter regularly? Also try taking a garden hose to you outdoor unit. If it get dirty you will not get near the effency of a clean one.

I change my filter at least once a month if not sooner. So the coils could be clogged causing this problem?

I can not see your indoor coil being cloged if you change your filter that often. I would try hosing off the outdoor unit coil first.

I cleaned the outside unit and still same problem. The a/c runs and runs even after the thermostat reaches the temp setting and I have to kick it up to get it to shut off. My outside unit is in direct sun could this be an issue? It's a brand new thermostat a manual digital by honeywell.

I'm not an expert in this subject by any means. But I DO know that my old apartment unit was always blowing on, even though it was cold, and it was due to bad isulation. If your windows/doors/walls are letting heat in, and cold air out, the AC will continue to try to keep up with it until it eventually either freezes over, or burns the motor out.


Again, I don't know anything about AC units, but this is what happened to me :) good luck

If the inside coil is clogged would that keep my ac from shutting off when the t stat reaches desired temp?

I usually have to shut the ac off manually and this time the temp dropped one degree after shutting it off. Doesn't make any sense to me

The guy my uncle had me call said it feels like the vents aren't blowing out hard enough but like I told him it works fine at night. It kicks on and shuts off. Last year I had a water leak at the evaporator coil on top of my furnace could this be clogged and causing unit to never want to kick off?

What brand t-stat did you install?

A honeywell rth111/rth221 manual digital