Articles by John Tomczyk

Technician inspecting outside condensing unit. - The ACHR News

Don’t Just Add Refrigerant to a System Before You Know the Issue

Talk to customers and be sure of diagnosis before taking action
John Tomczyk
March 4, 2019
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.
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Troubleshooting a Warm Freezer

Taking the right measurements can help pinpoint the problem
John Tomczyk
February 4, 2019
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.
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ABCs of Externally Equalized TXVs

Devices can improve evaporator efficiency in refrigeration and air conditioning systems
John Tomczyk
January 14, 2019
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.
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Seven Telltale Signs of a System Overcharged with Refrigerant

System checks result in faster troubleshooting
John Tomczyk
August 6, 2018
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.
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