Why does my home air conditioner keep turning off?

Question

We have central air, but lately the A/C unit will turn off when it is most needed. We have the thermometer set at 74F but it seems to turn off randomly or not turn on even when the temperature on the thermo shows 81F. I can get it to come on by setting it at 68F and turning it off then back on at the thermo, but it usually turns off a short while later or when we turn the thermo back up to the low 70s. Any help would be greatly appreciated.

Answer 1

The thermostat may be messed up.  Call someone to come and see if it is calibrated correctly.

Answer 2

There should be a white 1" pvc pipe (or possibly copper) coming out of the unit that inside your house and it should have a cap sticking up from it.  Remove the cap to see if there is any water backed up inside of it.

It sounds like that drain pipe may be clogged and the water is backing up into the a/c unit.  If so, it is turning itself off to keep the water from destroying your floor.

If you do find water in there, suck it out with a wet vac and pour some vinegar into it (the acid will clean out most blockages).

Edit:

Oh, and check your filter.  They should be replaced about every 1-3 months (depending on usage).

Answer 3

you might need to clean it the unit that is in your yard or it could be the switch is worn out . I had to get a new switch on mine when it was acting up.

Answer 4

We had a problem with our split system where it wouldn't go on properly. It turned out to be the circuitry. During the season when you don't use your A/C you should turn it off with the switch located on the outside unit. Leaving the outside unit switched on all year round can wear the circuitry out.

Answer 5

I can think of two things that might cause this:

1. Thermostat might be defective.  You might be able to replace it without paying for a service call.

2. The AC might have a thermal shutoff for when it overheats (due to an overload).  This would require a serviceman to diagnose and repair.