Amerex OEM Mechanical Release Module - 28318

The Amerex Mechanical Release Module, or MRM, is the control head of the Amerex KP Restaurant Fire Suppression System, the pre-engineered wet chemical system that protects commercial kitchen hoods, ducts, plenums, and dedicated cooking appliances. This kit (P/N 28318) is the OEM replacement module itself, packaged with the mounting bracket (P/N 28226) and backplate (P/N 11977) needed to install it. The MRM is the component that decides whether a fire event triggers a full system discharge, so it must be the correct OEM part for the installed KP system, not a generic substitute.

The MRM is a spring-loaded mechanical device with a mechanical input and electrical, mechanical, or pneumatic outputs. A single MRM can actuate from one to ten agent cylinder and discharge valve assemblies using a single nitrogen cartridge, making it the central decision point for systems protecting anywhere from a single fryer station to a full multi-appliance hood line. The enclosure includes a system status indicator and a window for visually verifying nitrogen cylinder pressure during inspection, along with provisions for tamper seals after testing or service and knockouts for conduit on three sides.

How the MRM Triggers a System Discharge

In automatic operation, fusible links positioned throughout the detection network are connected by cable back to the MRM. When ambient heat at a protected appliance reaches the fusible link's rated temperature, the link separates, releasing tension on the detection cable. This tension release trips the MRM's spring-loaded mechanism, which punctures the nitrogen cartridge. The resulting nitrogen pressure opens the valves on the agent cylinders, sending Amerex KP liquid agent through the discharge piping and out the nozzles over the hood, duct, plenum, and appliance surfaces. The same MRM can also be triggered manually from a remote pull station, typically located 10 to 20 feet from the cooking appliances, providing a manual override independent of the automatic detection network.

On discharge, a piston in the MRM also pulls a cable connected to the latch on the system's mechanical gas shutoff valve, releasing the latch and allowing a spring to close the valve and cut fuel to the protected gas-fired appliances. The MRM additionally has two pre-installed SPDT micro switches used for electrical shutdown of appliances and for triggering alarm or notification signals to the building fire alarm system.

The Amerex KP system, including the MRM, is a pre-engineered system as defined under NFPA 17A and must be installed, serviced, and maintained only by an Amerex factory trained and certified KP Systems distributor. Installing or servicing this component outside of that certification is not permitted under the system listing and can compromise the system's ability to perform during an actual fire event.

• Monthly Visual Inspection: Confirm the system is in the armed and ready condition, the MRM status indicator and nitrogen pressure window read correctly, and the remote manual pull station is unobstructed and accessible.
• Semiannual Professional Service: Required under NFPA 17A and NFPA 96, this service must be performed by a properly trained and qualified technician and includes a full test of the MRM, the detection network, the manual pull station, and all mechanical and electrical actuation components to confirm they are in operable condition.
• Mandatory Fusible Link Replacement: Metal alloy fusible links connected to the MRM's detection network must be replaced, not just inspected, at every semiannual service interval, since links that appear undamaged may have accumulated thermal stress that alters their rated actuation temperature.
• 12-Year Hydrostatic Test: NFPA 17A requires wet chemical agent cylinders in the system to be hydrostatically tested every 12 years.
• Post-Discharge Service: After any system activation, the MRM and full detection and actuation network must be inspected, reset, and recertified by a qualified technician before the system is returned to service.

A fixed KP system does not eliminate the separate requirement for a portable Class K wet chemical extinguisher within 30 feet of protected cooking appliances under NFPA 96 and NFPA 10, for use during flare-ups, re-ignition, or any period when the fixed system is offline for service.

Can I install this myself or have a general handyman install it?

No. The Amerex KP system is a pre-engineered fire suppression system, and the MRM is its central actuation component. Installation and service must be performed by an Amerex factory trained and certified KP Systems distributor. Improper installation can prevent the system from discharging correctly during a fire and may void the system's UL listing.

Why does this kit include a bracket and backplate along with the module?

The MRM bracket (P/N 28226) and backplate (P/N 11977) provide the wall mounting hardware required for a proper OEM installation. Ordering the complete kit ensures the replacement module is installed using Amerex-specified hardware rather than improvised mounting that could affect the unit's alignment with the detection cable network or gas shutoff linkage.

How many cooking appliances can one MRM protect?

A single MRM can actuate from one to ten agent cylinder and discharge valve assemblies from a single nitrogen cylinder, so the appliance coverage depends on how the certified distributor designed the specific kitchen's protection scheme rather than a fixed number tied to the MRM itself.