Refrigerant Charge Verification

Anchors Aweigh Energy LLC


Refrigerant Charge Verification


Most residential air conditioning systems are split, meaning there is a condenser outside your home where the heat is dumped, and an evaporator coil inside your duct work where the heat is absorbed. Between these two pieces of equipment are two refrigerant lines, one larger line (suction line) which brings the vapor caring heat back to your compressor from the evaporator coil and one smaller line (liquid line) which brings the refrigerant compressed back to a liquid from the condenser coil to the evaporator coil. 


If there is not enough refrigerant in your system then the compressor has to work harder with less refrigerant to carry the heat from indoors to outdoors. If the system is over charged, then you risk damaging the compressor in the condensing unit because it is only meant to compress vapor, not liquid, and when there is too much refrigerant in the system liquid refrigerant could make it back to the compressor. 50 to 67 percent of currently installed air conditioning systems have improper refrigerant charge causing a 20% loss of efficiency1. Along with this loss of efficiency is reduced equipment life and higher maintenance costs.


HERS refrigerant charge verification requires a test for target super heat on capillary and fixed orifice units, and target sub cooling when a TXV is installed. Target Super Heat or Sub Cooling must be provided to the HERS rater from the installer by way of the manufacturer specifications.


If your project has a split air conditioning system attached, and you replaced just the furnace, you still have to have a refrigerant charge verification. The reason being if you change the fan blowing over the evaporator coil then the charge is not accurate anymore unless you are delivering the exact same amount of airflow. The refrigerant charge is highly dependent on the actual system airflow. Copyright 2013 Bruce Cheney, Anchors Aweigh Energy LLC

Have refrigerant charge verification questions? Call AAE now at 858-254-1189

1. Proctor 1996, Downey and Proctor, 2002.