HVAC Not Cooling, sometimes.

Arnie Goetchius · 2015-08-24T21:08:41+00:00

I have a new 4 ton A/C and gas furnace installed in Jan 2015 by a contractor. This replaced a Colman 4 ton that I installed myself about 25 years ago. The new A/C Condensing Unit is a Trane 4 ton 4TTR3018-60. The A/C has been running all summer with out a problem. Today, after being off for a couple of hours, it started up and the following happened: (1) the house lights blinked for about 1/4 to 1/2 second. (2) the condensing unit ran twice as loud with more vibration as it normally does for about a couple of minutes and then it resumed its normal noise/vibration level. (3) During the time it was running, there was absolutely no cooling. The temperature at the bonnet was the same as the temperature at the return air duct. I shut the A/C down by adjusting the thermostat up and called the service tech who is coming tomorrow morning. After waiting an hour, I dropped the thermostat and it started right up with no lights blinking. The bonnet is running about 14-16 degrees cooler than the return duct which is normal. When I read the specs for the compressor, it says the following: "The Climatuff® compressor features internal over temperature and pressure protector, total dipped hermetic motor and thermostatically controlled sump heater. Other features include: roto lock suction and discharge refrigeration connections, centrifugal oil pump, and low vibration and noise." Question: Is it possible that the compressor detected a problem and just shut down but the Condensing Unit fan would still keep running? Also would a 1/4 to 1/2 second blinking of the lights be symptomatic of the problem?