Amerex Safety Disc, Gasket & Nut Assembly (Pack of 6) - 04000-P006

The Amerex Safety Disc, Gasket and Nut Assembly (P/N 04000) is an OEM pressure relief component used in Amerex CO2 fire extinguishers, specifically the Model 320 and Model 322 carbon dioxide units. This assembly functions as a rupture disc style safety device, designed to vent the cylinder's internal pressure in a controlled way if the unit is ever exposed to conditions that push internal pressure beyond the safe operating range, such as extreme heat from a nearby fire.

Because CO2 extinguishers store their agent under significant pressure without a separate expellant gas, the safety disc is one of the components a technician inspects and may replace during scheduled maintenance and hydrostatic testing. This listing is a pack of 6, sized for technicians and shops servicing multiple CO2 units who want to keep this consumable on hand rather than ordering a single assembly at a time.

CO2 extinguisher service involving pressurized components should be performed by a certified fire equipment technician with the correct training and equipment for handling pressurized cylinders safely.

• Confirm Model Compatibility: This assembly is specified for Amerex Model 320 and 322 CO2 extinguishers. Confirm your extinguisher's model before ordering, since safety disc assemblies are not interchangeable across all Amerex CO2 models.
• 5-Year Hydrostatic Test: CO2 extinguisher cylinders require hydrostatic testing every 5 years per NFPA 10, and the safety disc assembly is among the components inspected and potentially replaced during this service.
• Replacement Trigger: A technician replaces this assembly if it shows damage, has activated due to an overpressure event, or as part of standard practice during scheduled maintenance and recharge.

What does this assembly actually do?

It acts as a controlled pressure relief point on the CO2 cylinder. If internal pressure rises beyond the safe operating range, such as from exposure to extreme heat, the disc is designed to rupture and vent pressure in a controlled way rather than risking an uncontrolled cylinder failure.

Will this fit other Amerex CO2 extinguisher models besides the 320 and 322?

This specific part number is listed for the Model 320 and 322. Amerex uses different safety disc assemblies for other CO2 and nitrogen-pressurized models, so confirm your specific model before ordering rather than assuming compatibility.

Can I replace this myself?

No. This is a pressure-bearing safety component on a pressurized cylinder. Replacement should be performed by a certified fire equipment technician with the proper training and equipment for safely servicing CO2 extinguishers.