Heating, Air Conditioning, Fridge, HVAC/HOME AC

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Question
AC IS RUNNING 30 MIN. BEFORE IT STOPS. IT COOLS. I HAVE IT SET AT 79. IT STAYS OFF 18 MIN. KEEPS AT 79 IN THE MORNING.  BUT AFTERNOON IT GOES UP 1 OR 2 DEGREES AND IT DOES NOT SHUT DOWN UNTIL I MATCH SETTING 80,81,UP TO 84. THEN I JUST TURN UNIT COMPETELY OFF.  COME NIGHT TIME I TURN IT BACK ON AND IT STARTS TO WORK AGAIN.  TECH CAME AND ADDED FREON. MY QUESTION IS WHY IT KEEPS RUNNING SO LONG. RIGHT NOW IT CAME ON AT 11:25 AND I HAD TO SHUT IT DOWN 12:04 STILL AT 79. FELLS COOL. JUST STAYS ON AND ON,AND ON.
THANK YOU

Answer
Rose,
The thermostat on your wall is the switch for turning your AC unit on and off.
The thermostat is activated by the temperature of the air.
If you set the temperature at 79 the thermostat can't turn the air conditioning on and off both at the same setting, there has to be a differential. If you set it to 79 it might start the AC at 78 and turn it off at 80 or some where in between more or less depending on the accuracy of the thermostat. Depending on the heat load and the ability of your house to keep the heat out and hold the cold in will very from morning to night which can change the amount of off time depending on conditions.
some thermostats are more accrete then others, some can be adjusted for longer or shorter cycles.  

Heating, Air Conditioning, Fridge, HVAC

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Jim Barnhart

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Fifty + years conditioning the air.

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Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

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