Checking the acidity and/or moisture content of refrigerant oil is one of the methods used to test if a refrigeration system is clean and uncontaminated. But how can you take an oil sample without an oil plug?
Bob and Tim have gone back to the job with the grounded compressor. They changed the compressor yesterday and ran the unit for a few minutes, then shut the system down, leaving the crankcase heat on so they could start it up later. They now want to determine why the compressor burned.
Bob and Tim were on their way to a no cooling call at a commercial building. When they arrived, they talked to the building manager and checked the thermostat. It was set at 72°F but the thermometer was reading 78°. Tim said, “The fan is running, so there is control voltage and the thermostat seems to be calling for cooling.”