Troubleshooting The unit will not shut off at the set temp on the remote. It keeps running all the time. Is there a internal thermostat that can be replaced

It could possibly be in the unit but my first guess would be in the tstat or the wire. If the compressor contactor was sticking the coil would freeze because I don't think the blower would continue to run. Check the wire near the unit for rodent damage or simply dry rotted. Therefore the wires are touching each other and not shutting off. Also be sure your tstat is not overshooting the set point because it is trying to get to your humidity set point. This is referred to as temperature droop. Also verify it does not have a minimum run time. Good luck

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Have you cleaned the air return filters ? Wash them, don't vacuum or brush them. It damages the filter screen. Sometimes a thermostat will be out by a few degrees. If the filters are clean, try turning the temp down a bit to 65 degrees and see if the air con shuts down. ( If your room temp is showing 70, it should switch off the machine) If it doesn't turn off, keep reducing the temp by 5 degrees at a time and wait a few minutes each movement to see if and when it shuts down. If the machine keeps running, I would suggest your thermostat is shot and you will need a new one.

Put in a 5 minute time delay. It is a two wire device in line with the contactor. Sounds like it is set to 75 turns of at 74 and repeats. The tstat should have a differential of 2 degrees as well.

Could be either, Thermostat or fan relay on unit. Make sure thermostat fan switch is set to auto

I want to give a simple explanation before I go any further. On the heating side of a unit even though tthe temp has satisfied the thermostat, the fan will run until it cools down the plenum where the air flows from the air handler. There is a bimetal switch called a fan limit that operates the blower when the plenum reaches the temp set on the fan limit switch. Now if your fan keeps running even after the plenum chamber has cooled down, then you could have a fan limit switch that is stuck in the run position and must be replaced in order to correct the problem.

Hi!!
If when the desired temp. is reached, the compressor and condenser motor (outside unit) will shut off but the blower in the inside unit will keep working when the thermostat is set to Auto, the problems could be 1 - thermostat unit defective, and 2 - blower motor starter relay defective.
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Hi, the tech should have been able to figure the stat out with out a manual to see why the condenser is shutting off at 1:00 P.M. This is unusual for this to happen, unless it was winter and this is a heat-pump going into defrost, but just the fan would shut down. Does this unit have a box on it that was installed by your electric company that shuts the unit off during high peak conditions in the summer? This would cause it to shut down at the same time everyday. If not, it would have to be something in the thermostat that is set for it to shut off at that time. It still does not make since, as it would shut both the indoor and outdoor unit off, not just the condenser. Are you saying that just the condenser fan motor is shutting off, but the compressor continues to run until it shuts off on high head pressure when the fan stops, or does the complete outdoor unit shut down fan, compressor and all at that time??. It sounds to me like this outdoor unit has a time delay relay that has a fault in it may be shutting it off at this time daily? Please let me know if its just the condenser fan motor that shuts off, or if the complete unit is shutting off all together, this will help .
Sincerely,
Shastalaker7
A/C, Heating,

If your unit is running 24/7 you are either low on charge or the unit is to small for your house.
A 20° temperature difference is about normal for the room air vs the air coming out of the ducts, but the room air and the leaving air should keep getting colder and colder.
An air conditioner should cycle approximately 3 maybe 4 times in an hour if it's properly sized.
As for the thermostat thermometer they are very cheap and are more for reference than actual temperature, so if 78° is not comfortable, then you should set it lower but not rely on thermostat being accurate or what the thermometer is saying as long as it is consistent.
The air conditioner and thermostat can also be set below 78°, there's a lot of people set them at 72° and below with no problems.
the only thing is if you have real low humidity you'll need to watch indoor coil or the suction line (the big line) on your outdoor unit and make sure it doesn't freeze up on you.

the temp coming out of the vent should be 20 to 25 deg more then room temp and if AUX heat kicks in the temp should be even more.

I believe the problem in lies in the dual stage heat mode setup on the thermostat, but the unit going into defrost does make the unit act kinda strange. Even more so than other types of equipment. I would suggest hiring a licensed HVAC service technician if the problem cannot be resolved by yourself.