Bob and Tim were doing a routine service contract call. They had fastened gauges to the compressor at the condensing unit and had a temperature lead fastened to the suction line at the evaporator coil. They were observing the pressures and temperatures and Tim said, “The suction pressure is not stable. Isn’t it supposed to be stable during a long running cycle?”
The Sporlan Division of Parker Hannifin has unveiled CHILLSKILLS Sporlan Online Training, a new training website specially designed to provide self-paced online modules to help customers understand Sporlan products and the HVACR industry.
HVACR contractors who replace TXV valves during servicing are always seeking ways to carry the variety of valves they need in their vans or trucks. One new approach comes from Danfoss with its Maximizer and Minimizer kits, which package multiple TXV combinations in one place.
One of the basic components selected when installing a walk-in cooler/freezer or any field-assembled refrigeration system is the metering device, typically the thermostatic expansion valve (TXV). The TXV needs to be selected to match the Btu capacity of the system’s evaporator and compressor.
This article explores how a restricted metering device will affect system performance and efficiency. The system is a commercial refrigeration system with a TXV as the metering device. The refrigerant being used is HFC-134a. Very similar results will occur if an automatic expansion valve (AXV) is used.