Roof AC compressor kicks off in high temps

[skes]

My Coleman Mach roof top AC compressor started kicking off when the outside temps were high 90's and above (assume the roof top temps were much higher). The compressor kicks off but the blower stays running. Runs great when the outside temps fall to low 90's, but the interior temps were already in the 90's. I was able to get a shop to do a quick check while in AZ. They thought it might be the control board or even the freeze sensor failing. Also, just prior to heading to AZ, I installed a SoftStart which adds to the troubleshooting. I read on some other forums that others have had a similar issue but did not see a resolution. I'm now back to Michigan and it is Oct, so it will be impossible to recreate. Other than never going where the temps hit 100 (which I'm fine with!) any other thoughts? TIA!

[Ray,IN]

JIC the evaporator coil is freezing up, always run the fan in high setting. Freezing up is in itself another problem, might be dirty coils, slightly low refrigerant, or the plenum that separates chilled air from return air is not completely sealed, which greatly reduces efficiency and contributes to evaporator coil freezing over.

[Rich F]

We had the same problem in the Badlands this summer when the temp got to 109. The compressor shut off but the fan kept running. I too have a soft start and called them to rule this in or out. They told me the compressor has an automatic shut off when it overheats. Not sure what that temp might be but I'm guessing high 90s or above. We had to leave and drive east to Sioux Falls area. Temp was 92 and it ran fine from that point on.