The homeowners of a medium-sized house complain of reduced airflow coming from their registers during the summer. Their air conditioner is a 4-ton (48,000 Btuh), R-22 split system with the A-coil in the plenum of the furnace located in the basement. The evaporator has an orifice for a metering device, and the condensing unit is located on the east end of the house.

A grocery store owner in Georgia does a daily inspection of all refrigerated and frozen case temperatures using a laptop computer with specialized commercial software.

The TXV also simultaneously controls a set amount of evaporator superheat while, under these same conditions, assuming the range and capacity of the valve is not exceeded.

To obtain the heat content (enthalpy), it would be necessary to know both the pressure and temperature at this point and then use a thermal dynamic superheat table for this specific refrigerant.

Get insight from renowned HVACR professor at Ferris State University and NEWS columnist, John Tomczyk, in this 44-page eBook covering a wide range of service and troubleshooting topics.

Get insight from renowned HVACR professor at Ferris State University and NEWS columnist, John Tomczyk, in this 48-page eBook covering a wide range of service and troubleshooting topics.

If a condenser coil is dirty or fouled, its ability to reject heat is severely affected.

Refrigeration systems can become restricted in both their high and low sides for a variety of reasons.

Refrigerant floodback occurs when liquid refrigerant enters the compressor’s crankcase during the running cycle. Refrigerant floodback will dilute the compressor’s oil with liquid refrigerant, which will cause oil foaming in the crankcase, washing the bearings clean of their lubricating oil.

Consider the same system as last month’s column — a medium-temperature refrigeration system incorporating a liquid high-side receiver, a TXV as the metering device, and R-134a refrigerant — but the measured and calculated values are listed in Table 2, along with this detailed system analysis.