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Examples of Cycle Stop Valves on Residential Systems Older type water systems used a pressure tank and a pressure switch for pump control. The pressure tank would fill at the full rate of the pump until the pressure reached a high or cut out point and the pump was shut off. The draw down or amount of storage in the tank could then be used at whatever rate was required in the house. When the tank was empty the pressure would be at the low or cut in pressure and the pump would be started. This process was repeated over and over at a rate determined by the size of the pump and the amount of draw down in the tank. Even small pumps with large tanks could cycle on and off excessively when using any flow less than the full flow rate of the pump. This cycling causes water hammer and can prematurely destroy the equipment in a water system. The one inch Cycle Stop Valve is made for pumps up to 30 GPM and has a 1 GPM minimum. This will keep the pump running, maintaining a constant pressure, as long as at least 1 GPM is being used in the system. A Cycle Stop Valve set at 50 PSI will maintain 50 PSI when the house is using from 1 GPM to the maximum the pump will produce up to 30 GPM. When there is no water being used the 1 GPM minimum going through the Cycle Stop Valve will then enter the pressure tank until the pressure reaches 60 PSI and the switch shuts off the pump. The draw down or stored water in the tank can then be used as needed in the house. Ice makers can fill, toilets can be flushed, and tooth brushes can be washed before the pressure lowers to 40 PSI and the pump is started. Once the pump has started the Cycle Stop Valve will keep the pump running until there is no more water being used. The following are different ways of using Cycle Stop Valves on residential systems. Check the Cycle Stop Valve operating specifications making sure that the valve you choose can handle the pump you have. Example 1 An example would be a 3 HP 25 GPM pump set at 200 ‘ with a static level of 100'. The largest zone in the sprinkler system is 20 GPM and requires 50 PSI. We have decided on a tank that holds 10 gallons of draw down and will be installed with a Cycle Stop Valve. Shut off head of this pump is 460'. Subtracting the static water level (100') from the shut off of the pump (460') we get 360' or 156 PSI as the back pressure on the Cycle Stop Valve. The CSV1 can only handle 150 PSI and should not be installed indoors. The CSV1Z can handle up to 400 PSI and has no problem being installed indoors. Make sure that all plumbing between the Cycle Stop Valve and the pump can handle the maximum of 156 PSI. The CSV1Z has a minimum of 25 PSI friction loss and 12 PSI of reduced pressure fall off at 20 GPM. This means that we should add the 25 PSI or 58' of head to the TDH required from the pump. Maximum pumping level is 180', added to the 58' and the 50 PSI or 115' of pressure required gives us a total head of 353'. This pump can deliver 22 GPM at 353' of head which is more than enough to run our largest zone. Because of the 12 PSI fall off pressure, we must set the pressure on the Cycle Stop Valve 12 PSI higher than the 50 PSI required. Adjust the Cycle Stop Valve to hold 62 PSI while running about 2 GPM from a hose bib. Then turn off all water outlets and wait three minutes while the tank fills at 1 GPM. After waiting three minutes for the tank to fill the pressure has reached 68 PSI and the pressure switch is backed off until the pump is shut off. After opening a hose bib in the system the pressure tank drains until the pressure drops to 48 PSI and the pressure switch starts the pump. The Cycle Stop Valve will now hold 62 PSI if 2 GPM is being used and 50 PSI if 20 GPM is being used. Only when flow needed is less than 1 GPM will the Cycle Stop Valve allow the tank to fill to 68 PSI and the pressure switch will shut off the pump. Example 2 Another example might be a 1 HP 15 GPM set at 100' and needing 40 PSI. A CSV150 is selected and is to be installed in the well. Using a weight bearing coupling or (CSC) the CSV150 is installed under the pitless adapter which is 6' underground. A 5 gallon draw down pressure tank installed in the house and is about 15' higher in elevation than the installed Cycle Stop Valve. With the CSV150 holding 50 PSI at it’s elevation, we will see 6.5 PSI less or (43.5 PSI) at the elevation of the tank. After closing off all water usage the pressure will rise to about 52 PSI at the tank in about three minutes. At this point the pressure switch should be backed off until the pump shuts off. Cycle Stop Valves can be installed in many different locations on many different pump systems. Questions about your installation are welcome. (See Also "Sizing a Tank for Residential Systems with Leaks") |
| Cycle Stop Valves® is a registered trademark. All right reserved unless prior authorization is obtained. Cycle Stop Valves are patented: Patent number 5,988,984 and other patents pending. |
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