Articles by John Tomczyk

John Tomczyk discusses the Wye or Star configuration of the three-phase electrical service, which usually delivers four wires to the building.

When refrigeration systems are exposed to low-ambient conditions, the condensing pressure (head pressure) will fall. If the head pressure gets too low, the metering device will not have enough pressure drop across it to operate properly.

The thermostatic expansion valve (TXV or TEV) is a metering device located between the liquid line and the evaporator. 

John Tomczyk, Professor of HVACR at Ferris State University and co-author of Refrigeration and Air Conditioning Technology, discusses refrigerant undercharge.

Clear, concise, and accurate communication between service technicians, parts suppliers, customers, and the home shop is rapidly gaining importance as the HVACR field transitions and becomes more technically oriented.

During the off cycle, or especially during a long shutdown, refrigerant will want to travel, or migrate, to a place where the pressure is the lowest. 

When a refrigeration system has lost most of its refrigerant charge in a short period of time, the leak is probably significant and should be easy to find.

Compressor overheating is usually caused from high compression ratios. High compression ratios can be caused from a combination of high condensing pressures (temperatures) and low suction (evaporating) pressures.