Last year we blew off close to 40 sprinkler head tops at operation pressures of 50-60 psi during blow out. This was obviously unexceptionable and unexplained. These part circle heads should easily handle that pressure for blow. So this year we added a pressure regulator for blow out. The regulator handles temperatures up to 175 degrees and rated for pressures in the 150 psi range down to 5 psi. We set up the regulator so the pressure in the field was 30 psi. Well we had some luck we only blew 10 tops. But still why are the tops blowing off our part circle heads? We never had a problem when the new system went in 5 years ago. Possibly the plastic is photo degrading and the pressed in fitting are compromised. We are currently looking at a solution so next year we don't blow off any tops.
Regulator at 30 PSI