I did some research on these due to boredom at work and the fact being on a dept myself this vintage fire fighting equipment interests me. I found this site
http://www.vintagefe.com/pyrene.htmlit doesn't really say either way if they are refillable or not, but due to the fact it has what they reference as a "fill hole" on the the one could assume that as long as the pump mechanism works that u should be able to refill it to shoot water.
Hope this helps and hopefully the link works.
If I would read the rest of this web page I would've seen the part that talked about refilling these. Good Luck!!! Brent
