SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I live in Florida, recently bought a home with a hunter sprinkler system which uses a water well. My problem is that the PVC adapter coming out of the pump to the sprinkler system keeps on popping out as if there's a blockage somewhere along the line, pressure builds up and pops the fitting out. When I put everything back together, I have ran the zones (2 of them/ Hunter has 4 - no time is set on zones 3 & 4) and it works fine.. after a week of what seems normal running, I find that my fitting is popped out again.. any ideas?? a faulty valve?? any information is thanked in advance..

the fittings seem to be correct, I looked at two of my neighbors and the fittings are the same.. I did notice the last time that the 1' inch pipe going to the sprinkler system from the pump buldged out as if by pressure.. also the fitting that popped out was warped.. I went to an irrigation place yesterday (took the pipe w/ me) and they talked about a blowout/blowback (not sure if this is the term) caused by possibly one of the valves in the sprinkler system not opening hence causing the pressure in the system and blowing out the weakest link.. if this is true.. how can I check the valves themselves?? thanks again..

Fixed the problem, when I located the valves.. I found out one of the connections to the 2nd zone valve had been put together in a very Sh..ty manner.. no electric tape, no capping of the wires, no protection at all.. the wires had eroded and broke the connection, just enough to were they would touch intermitently. Hence causing zone 2 to be closed every now and then. When the valve was closed the pump would still be running, heated the water in the line warped the fitting coming out of the pump and popped the outgoing line from the pump.. the pump is still working fine, never had a lack of water..
Now that I have corrected the problem, everything seems to be working fine, I will continue to monitor it.. thank you for your help and advice