I have a 5-zone irrigation system with 1" Hunter PGV valves. This year, I have replaced the diaphragms twice in the same two zones after 10 years of trouble-free operation. All four of broken diaphragms had a small tear in the exact same spot. There is no debris in the valve body when I replace the diaphragm. These two zones feed spray heads; the others feed mostly rotors. Why would two of five zones start tearing diaphragms?

  • 1
    The only thing that I can imagine being different is water pressure. Have you noticed any change?
    – Tyson
    Aug 24, 2016 at 1:59
  • Nothing out of the ordinary pressure-wise. Hunter's support people emailed me to say if there's no debris, the valve must be out of spec and contact a distributor. Aug 25, 2016 at 2:19

1 Answer 1


I discovered that there was a part missing from the valves that kept blowing diaphragms. There is a white support ring that sits inside the valve body, under the diaphragm. On the two zones that kept failing open, it must have stuck to the diaphragm's plunger piece when it was first replaced. After replacing the missing piece (Hunter part number 331300), I haven't had a problem since.

FWIW, Hunter and their local distributor were worthless for sorting this out. Hunter blew me off with a talk to a dealer response, and the dealer said the part wasn't available separately from the valve. The support ring is available online, and is much cheaper than whole valves, even after shipping.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.