Author Topic: Pump Start Relays and Cycle Stop Valves  (Read 3746 times)

Cary Austin

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Pump Start Relays and Cycle Stop Valves
« on: November 05, 2014, 04:41:22 PM »
Irrigation systems with pump start relays can utilize Cycle Stop Valves to vary flow rates to different size zones. Pressure on the irrigation system will remain constant throughout the entire range of the pump. Zones can be matched to the needs of the irrigation and not the pump. This eliminates doubling up on zones when a single small zone is all that is needed.

When used with a pump start relay and in combination with a pressure relief valve the Cycle Stop Valve eliminates the possibility of destroying a pump from deadheading. Many times a pump start relay will start the pump even though varmints or trenching has destroyed the wires going to the zone valves and the sprinklers do not pop up. Set at 60 PSI the internal bypass in the Cycle Stop Valve will allow the pressure to increase to 70 PSI and the pressure relief will dump enough water to keep the pump from overheating.

One of the advantages of pump start relays is that irrigation systems can be made to drain out when not being used to prevent freezing. This can also be a disadvantage in that the system must be refilled to be used. Refilling the system can cause high velocities and water hammer, which can be hard on the irrigation system.

Using a Cycle Stop Valve with a small pressure tank and a pressure switch can have some advantages over using a pump start relay. With the pressure switch and tank the entire system stays pressurized. This eliminates water hammer and high velocities, which can occur from non-pressurized systems such as with the pump start relay. The pressure tank and switch will also allow automatic operation of the pump for using quick connectors, hose bibbs, and garden hoses.

Using Cycle Stop Valves with either a pump start relay or a pressure tank will maintain a constant pressure with any size irrigation zone. This allows precise irrigation and helps preserve our water supplies.