I'm installing an in-line chlorinator that states I need a check valve to prevent corrosive backflow if I have the following:
-preceding valves constructed of PVC or other plastic with metallic shafts
-heaters or other items with metallic tanks, shafts, coils, or tubes.
unfortunately, I don't have a clue...
I'll attach a link to pictures of my valves and heater. The heater is a Hayward H400 lDL2 lo-nox 400,000BTU unit installed in June of 05 if that helps. I've read over the info on the hayward site, and I still am not sure. As for the valves, I guess I could take one apart, but if someone knows if the shafts are metallic, it would be great!
http://i71.photobucket.com/albums/i159/ ... 030249.jpg
http://i71.photobucket.com/albums/i159/ ... 030251.jpg