I restarted a Canatal AC unit in a computer room this morning after an all-night shut down. It's a 15 ton unit with two Copeland scrolls. Was version 7, and was field upgraded to 9, about 9 years old.
One compressor would start and run for 2 or 3 seconds and shut off, then the other. Each time the display panel would say 01 or 02 of 02 compressors calling, and then it would change to 00 of 00 compressors calling. In other words the available compressors would decrease by one or two, leaving me without cooling. Sometimes just one compressor would be available. The problem is that both must run to cool the room. I kept re-setting the power supply and both compressor stages would show as available. But there's no reliablity here now!
I get no error/alarm messages. The compressors started cold and the condenser water was just right at 78 degrees. When they do run, all is fine.
Any suggestions on a solution?
I'll call Canatal in the morning but it's not always a rewarding experience.
Also would any know the password that keeps the display from signing out after a minute. I must have input the regular log-in password a hundred times last night.