HVAC Excellence 4

An evaporator pressure regulating valve (EPR) is used to keep evaporator pressure from dropping too low.

R-410A systems require TXVs with lower flow rates than R-22 systems.

A drain trap is only necessary on systems with horizontal airflow.

Air in the system will lower suction pressure and discharge pressure.

Compressor noise and overheating after startup may indicate low oil in the system.

Brazing copper to steel should be done with a 15% silver alloy.

Soap bubbles are an acceptable universal leak detection method.

The best time to check subcooling is while the system is off.

Overcharging a cap tube system results in high head and high suction pressure.

The presence of flash gas indicates ideal refrigerant conditions.