Cycle Stop Valves, Inc.

Two well system for a subdivision.

Pump #1 is a 3 HP 30 GPM submersible.
Pump #2 is a 5 HP 50 GPM submersible.

We want pump #1 to be shut off anytime pump #2 is required and can handle the demand by itself.

Pressure settings:

Pump #1
Cycle Stop Valve set 50 PSI.
Pressure Switch ON 50 PSI.
Pressure Switch OFF 60 PSI.

Pump #2
Cycle Stop Valve set 60 PSI.
Pressure Switch ON 45 PSI.
Pressure Switch OFF 70 PSI.

Small demands will be met by pump #1. Each pump needs it’s own pressure tank. When a tap in the system is opened the tanks will release water as pressure drops from 60 PSI to 50 PSI. At 50 PSI pump #1 is started and the Cycle Stop Valve on this pump will maintain 50 PSI on the system as long as demand is between 5 GPM and 30 GPM.

If demand goes to 0 GPM the Cycle Stop Valve on pump #1 will allow 5 GPM to fill the pressure tanks in the system to 60 PSI and the pump will be shut off. If the flow required increases above 30 GPM, pump #1 is no longer able to keep up with demand. The pressure in the system will drop to 45 PSI and pump #2 will be started. The Cycle Stop Valve on pump #2 will bring the system up to 60 PSI and pump #1 is shut off. The Cycle Stop Valve on pump #2 will maintain 60 PSI on the system as flow rates vary from 5 GPM to 50 GPM.

If the flow required increases above 50 GPM, pump #2 will no longer be able to keep up and the pressure will drop back to 50 PSI starting pump #1 again. If for instance 65 GPM is being used in the system, pump #2 will be pumping 50 GPM and the Cycle Stop Valve on pump #1 will maintain 50 PSI on the system by providing exactly 15 GPM extra. With both pumps running there will be up to 80 GPM available at 50 PSI for peak demands on the system.

When the flow required falls to less than 50 GPM, the Cycle Stop Valves on both pumps will allow the tanks to slowly fill to 60 PSI and pump #1 will be shut off. When demand is reduced to less than 5 GPM the Cycle Stop Valve on pump #2 will allow the system pressure to increase to 70 PSI and pump #2 will also be shut off. The next time water is required in the system, pressure from the tanks will fall to 50 PSI and pump #1 is again started. The above process is then repeated as required.

There are two possible problems with this application. The first problem could arise if the flow required never exceeds 30 GPM. If this is the case, pump #2 will never be used unless a timer is used to shut down pump #1 occasionally. Pump #1 could also be turned off manually. Any way pump #1 is shut off, pump #2 would automatically start and take care of the system.

The second problem could arise if the demand never decreases below 5 GPM. When demand increases above 30 GPM pump #2 is started which shuts down pump #1. If flow never decreases below 5 GPM, pump #2 will never be able to build the system pressure up to 70 PSI so that pump #2 will shut down and switch the system back to operating on pump #1. This can be easily solved by installing a bypass line around the Cycle Stop Valve on pump #2. This bypass can be adjusted to allow 10 to 20 GPM to go around the Cycle Stop Valve. When 20 GPM is bypassing the Cycle Stop Valve, anytime the system is using less than 20 GPM the system pressure increases to 70 PSI and pump #2 is shut down. This bypass can be adjusted as needed to make sure that pump #2 will be able to shut off.

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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