A/C not cutting off

If your thermostat will not shut off the air conditioner until set to 85F while the room is 75F, then the thermostat needs calibration or replacement.

You can buy several bad ones too. Start buying another brand!

If the compressor is still running when the thermostat is set to 'off' then you have a problem with wiring or the circuit board mounted relay. Most likely the relay unless you have been moving around wires recently, or replaced the circuit board and might have mis-wired something.

My guess? You need to replace the thermostat again, so that it will shut off while set at 77F when the room is 75 - 77F. Your thermostat seems to keep the compressor on when the room is 75F unless you turn it up to 85F - indicating that the calibration is off by 10F.

Fred.

I have non digital thermo I've already tried 2 of them I have a digital thermometer beside thermostat if I put thermo to where it will cut off and when it comes on again it knocks ac breaker off

You bought from a dealer and did not look before taking delivery?
You need to climb up there and inspect the roof to see if there are any problem spots.

gcroom wrote:
have to move thermo to 85 to get it to cut off any help would be appreciated

This evidence likely means that the stat IS working but IT is not cooling down as fast as the rest of the area.....as others have mentioned.

Any chance that somebody has re-directed the vents lately ??

In my C, I find that I need to point TWO of the ceiling vents in the general direction of the stat or it will run seemingly forever.

Bad stat even a new one might be bad. Do you have a refrigerator on the same wall? Might be heat from the refrigerator leaking to it. Is it digital or the old style mercury?

note heat doing the same thing not cutting on until 82

72 outside this morning still doing it just started k\last trip

Is this a new problem?

When it shuts down will depend greatly on the location of the sensor. One of ours is located near the front door in the exterior wall. If that wall is in the full afternoon sun, we may have to set the thermostat to 89 to get the AC to shut down.

if in the south it won't cut off unless in a good shady spot.most will not recover until late night early morninbg