And now I have a question regarding fire safety and Ansul systems. Who is permitted to install these systems? I am looking at $2200 for such a system installed for a 4′ exhaust hood. I can pick up a like new unit on CraigsList, with a 6′ hood for $625? Is there some mystery here for some nipple, fire bottle, switch box and nozzles? What gives? Is this something I could do with the right tools and pass muster on inspection? or do I need an authorized installer? What do you think? The wife says let em do it for the money, because she is worried regarding insurance. Help me out.