GX Pump 5K1

Overview

GX says the only real difference from the 5K2 is one cylinder instead of two. That means less power (900W) and slower fills, at about $600 less. You still get 4-stage compression to 5800 PSI (40 MPa) on 110V, water cooling with a built-in pump, radiator and fan, up to 10 hours of continuous running, twin-arm two-stage auto-stop, and automatic moisture bleed-off after each fill. GX rates a 6.8L tank from empty to 4500 PSI at about 90 minutes, and says it can fill tanks over 20L. Add one more burst disc if you fill over 5000 PSI. Before the first start, fill the cooling tank with about 500 ml of automotive coolant, and don't turn the grease knob for the first 6 hours. GX's tip for topping off a tank that already has pressure: start the compressor with the bottle valve closed, and open it once the compressor gauge passes the bottle pressure.