I did fire extinguisher service down in New Orleans in about '84. These guys are right about a yearly service call consisting of turning it upside down and tapping it to break up the cake and sticking a tag on it. The powder used in them, baking soda for a BC and ammonium phosphate for an ABC, is so fine that it will pack itself over the course of the year by just sitting there. The unit is charged with nitrogen for the propellant. Some states, however, require that you discharge the unit, clean and inspect the valve and syphon tube and affix a tag on the syphon tube to prove that you were in there. I think the reason for that is that Kidde used a plastic syphon tube with a cheesy clip holding it to the valve assembly that was notorious for being broken when you disassembled the unit. You would open up the extinguisher and the syphon tube would just be laying in the bottom of the unit! /forums/images/graemlins/shocked.gif With that not connected you would just get a blast of nitrogen if you had to use it. That would not be a good thing. We figured that the extinguisher had to be jarred to knock it loose but it must not have taken much of an impact because we rarely saw any dents or chipped paint on the outside. The weight of the powder flopping around during the test must have been enough to break it. Kidde was hard to get the clips from, we used to steal them from each others trucks. I don't buy Kidde for that reason. You are also supposed to hydro test them every 12 years but if you don't have any damage or rust on the cylinder I wouldn't mess with it unless you need to keep the tag up for insurance purposes. I took them to Baton Rouge to do that on the weekends, that gave me all week to take the CO2 units to bars, crack the door and stick the nozzle in and chase drunks out the back door. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif