Question
Several years ago I purchased a house that had a sprinkler system supplied by a lake. The system worked great last year and this year until recently. What is happening now is after the system cycles through the 6 stations and the pump cuts off so much pressure builds up that the discharge pipe is forced out of the pump housing. The housing discharge outlet is 3" threaded. When installed a 3" PCV threaded fitting was used to attach the sprinkler system plumbing to the pump. The pump is a Flotec FP5182 - 2hp. What can I do to correct my problem?

Answer
Thanks for your question.
My first thought is: are you sure all zones are operating? If one zone didn't open it would cause the pump to over heat and blow the fitting out of the pump. This is normally the reason fittings come out of a pump.
If your sure the zones are all running then I would suggest using a foot or more of galvanized pipe from the pump to the irrigation mainline. This will give you some strength at the pump and a little heat resistance is it over heats
Good luck, if you have more question, feel free to reply.

Matt