All Yamada diaphragms are rated to 100 PSI maximum and in many applications are run at pressures greater than 100 PSI without incurring diaphragm damage. Even though you can run diaphragm pumps dry, it is something that you should avoid for several reasons:
In the early months of 2008 the aluminum air chamber for the NDP-20 and NDP-25 series pump was modified with a groove in order to accommodate the newly designed diaphragms from Yamada. As a reminder the new air chambers will be marked on the outside of the casting with a “G” in order to make it easier to identify.
The starting serial numbers for both size series are: NDP-20/25 B/A/S – 487505
The Buna, Neoprene, EPDM, and Viton diaphragms will have the new design with the integrated lip. PTFE, Hytrel, and Santoprene wills till use the old design but will be used in conjunction with the following o-ring