65 is fine, but the symptom of air leaking doesn't in my experience correspond with a bad check valve. That will usually crack the plastic housing. If the regulator is bad, the pressure might creep up to 150-175 depending on your compressor.
Compressor is set at 80psi shut off. Local regulator for this
flojet is brand new and set at 65.
A little more background on the situation. When we took over the site there was a g57 kalrez on there leaking air bad. I replaced it with a viton model, when I came in next day outlet line was blown off (could have been my rookie clamping skills with oetiker clamps), air was leaking out of
flojet, and chemical all over the floor. Luckily
flojet stalled out and had stopped pumping, or there would have been more water everywhere. I replaced with another viton unit and seems to be holding for last 2 days without line blowing off or
flojet leaking air.