Refrigerant Filling Equipment Delivering Auto Leak Pre-Check for Charging Precision Refrigerant Filling Equipment with Automatic Leak Pre-Check Charging a circuit that already leaks wastes refrigerant, hides a fault and can send a defective unit further down the line. The HongCe HC-RF-P3 runs a short leak pre-check before the charge is released, so a leaking circuit is stopped while it is still cheap to fix. A short check before every charge The pre-check uses pressure decay