A/C only works durring the night......?

Question

The a/c in my house hasn't worked during the day for the last 3 days, yet when it becomes dark out it starts on it's own. It's all a new system that's 3 years old. It's worked great until now, I changed the temp. up and down from 80 to 84 daily to save energy and I'm wondering if that had anything to do with it. Right now it's set to 81 which is fine when it works....only with out it, the house gets to 88-90 durring the day.

Can anyone shed some light on this before i call an A/C tech.

Answer 1

is it possible that your thermostat is the type that can be programmed to do different things at specific times of day.  Perhaps it somehow got set to be off during the daytime (or temperature set very high) and on at night.

Answer 2

Most likely it's a bit low on Freon (refrigerant) and isn't working at full capacity, although this usually causes the indoor coil to freeze up, partially or completely.  The other possibility is that the outside (condenser) coils are partially plugged, again, reducing capacity.  When it cools down at night, head pressure drops a bit and it gives some cooling.  You may want to shut power down on the outside unit and give it a good flushing with a garden hose.  Make sure the water flushes right through the coils, being careful not to bend the aluminum fins with the water pressure.( try to blast it straight through the coils, rather than at an angle)  If the coil flushing doesn't do it for you, and you know that all components are functioning...and that the filter isn't plugged, then you're in for a service call.  Good luck.

20+ yrs hvac tech