What is the purpose of purging non-condensables?

• A. To reduce head pressure and restore system efficiency
• B. To remove moisture from the system
• C. To increase refrigerant charge
• D. To reduce the weight of the system

Answer: (A)

Purging non-condensables focuses on keeping the condenser performing properly. When gases that don’t condense (like air or inert gases) accumulate in the system, they act as an insulating layer above the refrigerant vapor and hinder heat transfer in the condenser. That means the condenser can’t reject heat as efficiently, so the head pressure rises and the compressor has to work harder. By purging these non-condensables, you remove that trapped gas, improve heat transfer, bring head pressure down, and restore overall system efficiency.

Moisture removal is handled by moisture control tools and dryers, not by purging non-condensables, so that isn’t the main goal here. Purging can also cause some refrigerant loss, so it isn’t about increasing the refrigerant charge. Reducing the system’s weight isn’t a purpose of purging either.