QuestionRecently our irrigation system experiences sporadic loss of prime during automatic start-up in the morning. We have a Hunter 9 Zone SRC residential controller with 9 zones, Hunter rainy day switch, a QP20 2HP Meyer irrigation pump, a Batrow pump start switch and 9 1.5" valves (5 Nelson and 4 Hunter). All components appear to be functioning properly. 2 PVC well points at 26' and 28' respectively were sunk approx 30' apart and deliver water to the pump in 2" PVC. A standard 2" PVC check valve is used 1.5' from the pump. Water is delivered to the 9 valves in a 1.5" PVC manifolded system after the pump then on to the irrigation zones.
At times during auto startup, the pump appears to lose prime and will continue to run freely thru the zone run periods without prime or water. However when I shut the system off and perform a manual start, the system will slowly prime and run perfectly thru all zones. The system works during manual operations. The check valve appears to hold pressure between itself, the pump, valves and manifolding but very gradually pressure drops to 0 PSI when the system is off. During one of its temperamental periods, it takes a minute or two and sometimes a switch on and off more than once of the pump to prime during manual starts of the system.
We have a high water table (5') as we are 700' from Lake Muskegon in a high water zone. There always appears to be plenty of water. Water pressure on the pump side is approx 40 PSI Max. The pressure gage reading fluxuates wildly (between 36 & 40 PSI) during operation. The pressure valve is mounted on top of a tee on the pump. Would a reserve tank help to resolve this temperamental loss of prime problem?
Please advise
Best Regards
Chuck Nauman
3284 Memorial Dr.
North Muskegon, MI 49445
[email protected]
Answer Chuck, pressure tank would be nice as far as the pump short cycling, but I think it may be short cycling due to leak in the suction line to the pump. The foot valve or check would be something else to check, but you sat it is good. The suction line must be tight! Look at fitting that are threaded and at any unions very closely first. A very small leak in the suction line will cause the pump too slowly lose prime as you describe. Jim
