Tech Tips # 31


The first of the wet chemical extinguishers are coming up for their first hydrostatic test, and as part of that procedure Amerex is recommending a complete maintenance/teardown. The following items are of particular interest:

1. We are hearing isolated reports that the agent sometimes changes color and becomes a light green/blue color. The color change is an indication of a reaction between the agent and the brass components of the valve assembly. At any recharge and at the time of complete maintenance, replace the agent with a new Amerex wet chemical recharge. It is important to always discard any remaining liquid in the extinguisher and to use a new Amerex recharge (see item 3). (NFPA 10 4-5.3.11)

2. Disassemble the valve and check the condition of the valve body, downtube retainer and valve stem. It is not uncommon for the brass components to be badly tarnished, but if there are any signs of corrosion replace the corroded parts. Amerex is currently using a plated retainer on wet chemical extinguishers. We believe this will minimize any reaction between the agent and bare brass parts, minimize corrosion and keep the retainer from tarnishing.

3. Since the new 3 liter Model 530 recharge is highly concentrated you may sometimes find some sediment in the recharge container. When recharging any Amerex wet chemical extinguisher use clean, potable water to add to the appropriate recharge agent, and thoroughly stir the diluted mixture to ensure any undissolved particles go back into solution. Also use clean potable water to mix with the Model 660 recharge for 2.5 gallon extinguishers, Amerex Models 262 and B262. Use nitrogen as the pressurizing gas to complete the recharging procedure.


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Amerex Corporation
7595 Gadsden Highway
Trussville, AL 35173
205.655.3271 p
800.654.5980 f