Air Conditioning - air conditioning freeze ay 72 degrees

Why does my central air conditioning unit freeze up at night? It has an A coil in the basement and the thermostat is set no lower than 72 degrees

I would recommend calling in a tech to look. You could have a leak somewhere in the system which is draining your R-22/410.

That would be my guess, but I am no expert.

The first check on a unit is .Is the filter clean,is the coil clean ,the blower wheel clean. if so next is you can be low on freon. Copper lines should be small coper line hot to warm ,big copper cold and wet .If not call a tech

How do you clean a central ac coil?

You have a low charge. Usually the unit with a low enough charge will freeze all the time. You, however have the rare slower leak, where during the day you have enogh heat load to keep the evap from freezing. But at night when the heat load goes down the evap freezes because of the low charge.

I suspect that you have a very small leak some where in your system. I'd advise to call aroungd and find a service company that uses dye.

Because if the leak can't be found using regular methods dye is the best thing.

This may mean a couple of service calls but it will fix it.

Chris