HVAC Compressor not always kicking on

[Xpress21]

Has anyone had this experience or know what is happening?

2 times (each time a year apart from each other) we have had our middle AC malfunction. The middle unit starts blowing air when we request a lower than interior temp but the compressor will not kick on. We can keep turning the AC unit off and leaving off for 30 minutes to and hour long then re-attempting to request cool air but the compressor will still not kick on and only hot air blows. Even manual override will not make the compressor kick on. On both occasions this happened we then turned unit off for a whole day. Both times after the unit has been off an entire day the unit starts to function the next day correctly with the compressor kicking on again and cool air blowing. We have asked several service people and we have been told ... can’t fix unless unit is currently having the issue.... so we still have not able to make the appropriate repair.

Any idea what this could be? Starter in actual AC unit? One repair man said low voltage house batteries but we did not think this would have anything to do with our issue.

2018 Anthem 44 B
Steve and Daphne Stanford

[garysfb]

I am not an HVAC expert and I HATE intermittent problems. I do know that if your A/C has been running a while with low refrigerant it will freeze up and kick the compressor off. And when you try to set it to turn on it won't start again until the ice melts. But it sounds as though you are setting it when it hasn't been running; and it doesn't happen all the time.

[MrMark52]

I just helped someone on FaceBook 911 forum fix his unit doing the exact same thing -

First - unplug or turn off power to the unit. Then go up on the roof and remove the shroud off the top of the unit, and then access the electrical box where all the wires connect from the compressor and the fan.

#1 - look for any burned wires. Very common to find wires that have burned open at the crimp,connectors.
#2 - inspect all terminal connections to the fan/comp run capacitor and the hard start device. The start device (usually a black colored “D” size battery or longer looking thing) tend to fail themselves.
And since the fan is running, the run cap is likely Ok - but they’re cheap, so if in doubt, replace it.
#3 - if any wire is partially discolored and the insulation is blackened and stiff, it is very likely failed and needs to be replaced. Best to use soldered on connections as they won’t fail like a crimped connector will.

Don’t let anyone tell you to check the refrigerant. These units are factory sealed and there is no way to check it - besides the fact that any unit manufactured in the last 20 have been designed to minimize leak points, a result of EPA regulation.

[jarwiebe]

Originally Posted by Xpress21

Has anyone had this experience or know what is happening?

......compressor will still not kick on and only hot air blows.....

2018 Anthem 44 B
Steve and Daphne Stanford

You mention hot air blows, are you sure your compressor is not kicking on? If the hot air is warmer than ambient, i would suspect a problem with the reversing coil (not sure of the proper name). That is assuming this is a heat pump.

[Xpress21]

Originally Posted by garysfb

I am not an HVAC expert and I HATE intermittent problems. I do know that if your A/C has been running a while with low refrigerant it will freeze up and kick the compressor off. And when you try to set it to turn on it won't start again until the ice melts. But it sounds as though you are setting it when it hasn't been running; and it doesn't happen all the time.

Good idea to check for freezing up and low Freon

I believe the last time it happened we had run the unit on 67 that evening most all night because it was so humid outside and stuffy inside. Thank you.

[Xpress21]

Originally Posted by MrMark52

I just helped someone on FaceBook 911 forum fix his unit doing the exact same thing -

First - unplug or turn off power to the unit. Then go up on the roof and remove the shroud off the top of the unit, and then access the electrical box where all the wires connect from the compressor and the fan.

#1 - look for any burned wires. Very common to find wires that have burned open at the crimp,connectors.
#2 - inspect all terminal connections to the fan/comp run capacitor and the hard start device. The start device (usually a black colored “D” size battery or longer looking thing) tend to fail themselves.
And since the fan is running, the run cap is likely Ok - but they’re cheap, so if in doubt, replace it.
#3 - if any wire is partially discolored and the insulation is blackened and stiff, it is very likely failed and needs to be replaced. Best to use soldered on connections as they won’t fail like a crimped connector will.

Don’t let anyone tell you to check the refrigerant. These units are factory sealed and there is no way to check it - besides the fact that any unit manufactured in the last 20 have been designed to minimize leak points, a result of EPA regulation.

Thank you we will check everything you have on your list

[CaptVern]

No 2 on my 2016 44B is doing the same thing. Winter of 19/20 in Florida - No 3 compressor would not kick on. Local tech replaced the Zone Control Box (Part no 9630-753) which we found on ebay of all places after an exhaustive search and it has worked fine since then. I suspect that either the timer or compressor relay is not making a firm contact or perhaps a burned wire or crimp fitting. I bought a spare April last year when I got home since it was still available on ebay which I plan to swap out in the next week or so. Now I can't find one anywhere on the internet.

[Dom]

are your condenser coils up top dirty? this would cause the compressor to cut out when it gets hot. Always a good idea to get a home up top and wash them out.