Oil separators are essential on low and ultra-low temperature refrigeration systems and on large air conditioning systems up to 150 tons. Most compressor manufacturers require oil separators on all two-stage compressors.

Years ago, in some dank basement, a contractor installed a large air vent near the end of a steam main. Why did he do that and what happened? Read to find out.

Contractors do not like to hear the word “callback.” They cost money and degrade a customer’s respect for and opinion of the service contractor. So how can a technician reduce the number of times he must revisit a repair? 

Grooved mechanical piping has been changing the way contractors do business for more than 85 years, but this method of pipe joining is still unknown or misunderstood in some areas of the commercial building industry.

Bob and Tim were just finishing a service contract call when they were contacted by the dispatcher about a no cooling call at a new installation at a small retail store. The weather was unusually warm for this time of the year.

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.”

Bob and Tim were on their way to a residence where the occupants said their unit runs all day long, but the space temperature rises to 82°F while the thermostat is set at 75°. The unit shuts off during the night and the temperature inside is 75° in the morning, but during the day it rises.

Bob and Tim have been sent on a call to a house with no cooling. The system has just been installed and the construction crew has been having problems with startup. The system has a capillary tube metering device and Bob and Tim begin looking at what may be wrong.

Many service technicians believe that frost on a suction line or on the compressor’s head itself indicates there is liquid refrigerant coming back to the compressor. Is this really true?