Cycle Stop Valves, Inc.

Using a Cycle Stop Valve on a large pump with a small pressure tank, the setting of the valve should normally be the same pressure as the pump starts. Using an example of a system that requires 60 PSI constant and a flow rate from 5 GPM to as much as 300 GPM we would do the following.

With centrifugal pumps or flowing wells with a static water level at ground surface, the full deadhead pressure of the pump will be the same as back pressure on the valve.

We determine from our pump curve that our pumps deadhead pressure is 150 PSI. With a Cycle Stop Valve setting of 60 PSI, there is a maximum differential pressure of 90 PSI, which is well below the 125 PSI limit. The Cycle Stop Valve will hold 60 PSI constant on the system. Pressure on the pump case will change from 67 PSI when the system is requiring 300 GPM, to 150 PSI when the flow needed in the system is only 5 GPM. When there is zero flow required in the system the Cycle Stop Valve will allow 5 GPM to fill a pressure tank. Using a tank that has 10 gallons of drawdown, the system pressure will rise to 80 PSI in two minutes, and the pressure switch will shut off the pump. When water is again needed in the system the 10 gallons in the pressure tank will be drained and the pressure will drop to 60 PSI. At 60 PSI the pressure switch will start the pump and the Cycle Stop Valve will hold 60 PSI steady matching the usage in the system.

Higher pressure pumps can be easily controlled using Cycle Stop Valves. Choose a pump that will deliver the maximum flow needed at the required pressure. Pick a Cycle Stop Valve that can handle the max flow and can be adjusted to the pressure required. Find the shut off head for the pump being used and subtract the static water level (if pumping from a well). This will give you the maximum pressure that will be held back by the Cycle Stop Valve. Make sure the Cycle Stop Valve chosen can handle this maximum pressure from the pump. We recommend that the differential pressure through the valve be less than 125 PSI. This means that the maximum pressure that is held back by the valve should not be more than 125 PSI higher than the setting pressure of the valve. If the differential pressure is higher than 125 PSI more than one Cycle Stop Valve may be needed to stair step the pressure down. The first valve would bring this back pressure down from 300 PSI to 175 PSI. The second valve in series would take the 175 PSI and regulate a steady 50 PSI to the system.

Small tanks are not mandatory. Pressure tanks of any size can be used with a Cycle Stop Valve. Tank fill rates can be adjusted and pressure switch band widths can be narrowed. Call the factory if you have any questions.

Cycle Stop Valves, Inc.
10221 CR 6900 Lubbock, Texas 79407 Send Email	800-652-0207 806-885-4445 Fax: 806-885-1994

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