The Truth About Refrigerant Charge

The Truth About Refrigerant Charge

Refrigerant Guages

All over the Internet you can find articles and blogs stating the “facts about refrigerant charge.” Most of the information seems to be great except when you read about adding or verifying refrigerant. You may be led to believe the only way refrigerant could be low is if the system is leaking refrigerant. While this may be true for package systems, it is not true for split systems.

In 2010, The California Energy Commission (CEC) required that all split air conditioning systems in climate zones 2 and 8-15, need to have refrigerant levels verified by a HERS rater when the following services are performed by an installer:

an airhandler is installed or replaced.

an outdoor condensing unit is installed or replaced in a split system, heat pump or air conditioner.

a heating or cooling coil is installed or replaced in a split system.

a furnace heat exchanger is installed or replaced in a split system.

These 3rd party HERS verifications were implemented because of the need for California to reduce it’s power consumption. When an air conditioning systems are under-charged they will not function at the highest efficiency and can cause damage to the internal components. The same applies for systems that are over-charged.

Split air conditioning systems are required to have a predefined amount of refrigerant per foot in the lines (normally 0.6oz per ft). When the units are delivered they are pre-charged with refrigerant for average installations. When the installer has to add or reduce the length of the lines, from the condenser to the furnace, the charge is no longer adequate. Also, the charge can be released by mistake or by installation error.

This is where refrigerant charge verification comes in. The two most common ways of verifying refrigerant are “subcool and superheat” and “the weigh in method.” Checking the refrigerant charge by the subcool and superheat method is much more accurate and helps diagnose other potential problems with the system. The most inefficient method of refrigerant charge verification is the “beer-cold” method. The “beer-cold” method is performed by charging the system until the suction line reaches a “beer-cold” temperature. I don’t have to tell you how accurate this method is.

Making sure HVAC systems are properly charged can save a large amount of money for the homeowner or business, by causing the unit to run less often and consume less energy.


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