My AC unit is being affected by a power loss during our storms. When we lose power and it is running it makes a strange noise as though it is still running but no air is coming out the inside vents. We have to shut it off at the thermostat and wait a bit then turn it back on and it's fine until the next time. I'm not sure what causes this any ideas will be helpful.

Fritoguy15

 

Power losses are a way of life and usually the system can restore itself. It sounds like your condenser/compressor is trying to restart too quickly. Some systems have a built in delay and many thermostats also that allows a delay of 5 minutes before trying to restart.

Try this..... set the temperature a few degrees over the room temperature. Wait 5 minutes. Now set the thermostat a few degrees below room temperature and see how long it take the outside unit to start. Two people make the job easier. Let me know what happens.

 

I understand what you're saying, but my concern was if we are not here at home when this happens how long will it run making that noise . Will my AC manual tell me if it has that delay switch on it or not?

 

No one can answer that question. I had something similar happen 20 years ago when I had a very old Westinghouse condensing unit with no time delay relays. Power actually went off.....and then right away back on and then off again....a few seconds later back on again. Bottom line is it locked up the compressor. Replaced with a Tempstar unit and never again had that same problem, it has a time delay relay. Hopefully something like this would trip the circuit breaker, but you cannot rely on it.


Probably not, but if you post the manufacturer and model number someone here maybe able to tell you.

 

Time delay's in a condenser are not written in stone. Many manuals will have it drawn in with dotted lines and say "optional equipment". With a make and model of the thermostat we could check on a delay there.

Even with all this..... a manual test is best as you can positively check for delay.

 

The Thermostat in a Honeywell model#RTHL3550D. Hope that helps.
Fritoguy15