Try use search. Been covered many times.
Recharging FE for people w/o contract w/ local Fire Protection Equipment co is not happening even when you have rechargeable units and most home users do not have them. Recharge cost more then most think plus many are "out of date" for DOT rules and causes more issues and higher cost even if can recert the tank.
IOW Most FPE co's Do Not recharge any Plastic valve and many metal valve units you get from Retail stores including online. Not even 15# or bigger "Dry Chem" units.
DIY recharge w/ compressed air is a no no. Might seem to work but Many "Dry Chem" will turn to "concrete" exposed to air. Most compressors output wet air, oily air or both and react w/ the chem's.
If you have Kidde units... check for Recall on many of them. see http://www.fiero.nl/forum/Forum6/HTML/121743.html
------------------Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)The Ogre's Fiero Cave
[This message has been edited by theogre (edited 11-04-2020).]