Compressor will not respond to thermostat.

Possibly a tstat issue. Run system until satisfied, once satisfied indoor fan shuts down compressor still runs remove tstat face plate and see if compressor shuts down. Another issue could be a sticking contactor for compressor. With a meter you could check at the contactor to see if you lose your 24volts for cooling but contactor remains pulled in.

If the contactor relay by your compressor does not open the compressor will stay running. Either the contactor is at fault for staying stuck OR the thermostat continues to send out the 24 volts to activate the contactor and keep compressor running

With a non heat pump it is a simple 24 volt AC control circuit. In the attic there is a relay that is actuated via the fan control wire directly from the thermostat. On the thermostat there is an auto/man switch that controls the fan. Manual the fan runs all the time. Auto fan turns on and off with the outside compressor.

If the system is not calling for cool and the fan continues to run the fan relay is sticking. common problem. Sometimes after running for several days the relay will stop sticking if not, replace relay.

If the system is calling for cool and the compressor stops I would still expect the fan to run until thermostat tells the A/C to off. Some compressor units include a safety switch or high-pressure cut-out switch A blocked internal valve bad control board or external fan in outside unit defective no air flow in outside unit.
High pressure cut out not good,

Suggest turning temp max cool and observe. If acceptable cool and the compressor runs without interruption all is good, except for the blower in the attic. Safely check relay in attic blower circuit.

Hope this helps.

check thermostat turn off system wait 3 to 5 minutes turn on to cool and turn thermostat to coolest setting if no compressor test thermostat and compressor check filter if dirty and coil iced turn off and lit defrost and change filter if coil warm and unit running compressor internal damage or low freon

I'm not sure if the thermostat is wired correctly. First, the thermostat is wired directly to the outdoor unit (compressor/condenser unit). It is NOT directly connected to the indoor unit. It connects to a low voltage control panel in the outdoor unit that sends a signal to your indoor fan/evaporator. This wire is called the fan relay switch and physically runs between the low voltage controls of the indoor and outdoor units. If the fan relay is bad it's possible that the unit runs continuously. To prevent destroying your outdoor unit there is a safety feature that prevents the indoor fan from shutting down while the outdoor unit is running. If the indoor fan did shut down while the outdoor unit was running than you would slug your compressor. That is, your compressor normally sees refrigerant gas but is instead seeing refrigerant liquid. That would not be good since this scenario would destroy your compressor. It sounds like a faulty fan relay. The actual contactor portion of the relay is in the outdoor unit.

Is it a digital temp. display? Does this show a low temp? It should show +/-34 degrees. Listen if the compressor runs continuously. It should run for a while and then switch off. When you change the temp setting, as you turn it down, the compressor should stop. If it runs continuously then the likely cause is a stuck/faulty thermostat.Before replacing this, switch off and leave open until unit is at room temp. Then switch on again and monitor. If the thermostat if faulty and the compressor runs continuously you can damage it by overheating. The compressor will run for a good few hours after restart, until set temp. is reached and then switch off automatically. Good luck!

Sounds like thermostat is failing. There is a factory set resistor that helps the thermostat keep a 2 degree accuracy. Second possibility is that you have a fan or direct airflow from the cooling system, being devirted, that is allowing the cool air hit the thermostat on the wall.

Small refrigeration units like this one like to fail to cool by developing a small leak and slowly
leaking refrigerant.
THERMOSTAT FAILURE CHECK:
A technician will check the thermostat using using a DMM (digital multimeter). But you can suspect the thermostat if you set the thermostat high and the compressor motor does not run,
then set thermostat low, and the compressor motor also doesn't run - in other words, the thermostat is failing to start the refrigerator's refrigeration system no matter what its setting - an obvious failure of the thermostat.
COMPRESSOR FAILURE CHECK:
If the compressor is dying, you would hear the compressor running almost constantly, but not
sounding quite right (uneven noise, clunking, tapping).
REFRIGERANT LEAK CHECK:
If you unit is low on refrigerant (due to a leak), the compressor motor will be running
almost constantly, but it will sound Ok.

Dear jack289,
The thermostat is not working properly. When thermostat cutsoff the compressor Please turn the thermostat knob to higher setting if compressor starts working then please change the thermostat. The fan will run continuously since only the compressor is controlled by the themostat.
Regards,
ramesh22

The Air conditioner are good only the adjustment of thermostat are the problem, select the thermostat in lower #3 you observe the thermostat will off in such time temperature reach to #3 If you full adjustment the compressor will not off.
In fan selector the compressor will autamatic off because no connection attached fan only .