Harris 25GX hydrogen Pressure Regulator / cng regulator 25GX-50-350

What pressure, flow and temperature is it rated for?

This regulator is rated for a maximum inlet pressure of 3,000 PSIG and delivers 0-50 PSIG adjustable outlet pressure. Flow coefficient (Cv) is 0.17, which translates to roughly 17 SCFM of air at typical delivery pressures, though actual flow capacity varies with inlet pressure, delivery setpoint, and gas molecular weight. The listing does not provide a temperature rating—ask the seller for the operating temperature range if your application involves extreme ambient or gas temperatures.

What gases is it compatible with, and has it been oxygen cleaned?

This unit is rated for hydrogen and methane service per the CGA E-4 certification and CGA 350 inlet connection. The listing does not indicate oxygen cleaning or oxygen service compatibility, and the recommended green oxygen gauge guard accessory suggests this particular unit is configured for fuel gas service. Single-stage regulators for hydrogen typically use CGA 350 connections and are not oxygen-clean unless explicitly stated.

What materials are the wetted parts?

Wetted components include a brass body, chrome-plated zinc bonnet, neoprene diaphragm, and one-piece encapsulated PTFE Teflon seat. The internal filter that protects the seat is also in the gas stream, though the listing does not specify its material—typically stainless steel or sintered bronze in industrial regulators. The outlet connection is 9/16"-18 LH threaded, standard for fuel gas applications.

What should I inspect before putting it into service?

Since this is listed as new condition, verify all protective caps are in place on inlet and outlet connections, check that both gauges read zero with no pressure applied, and confirm the adjustment knob turns smoothly through its full range without binding. Inspect the CGA 350 inlet threads and sealing surfaces for damage from storage or shipping, and ensure the internal filter is clear—debris introduced during installation is a common cause of seat leakage on new regulators. Before pressurizing, confirm compatibility with your specific gas composition and purity level, as trace contaminants or moisture can degrade neoprene diaphragms in hydrogen service over time.