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Cycle Stop Valve CSV1/1.25

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Cycle Stop Valve CSV1/1.25

Product No. Size Type Pressure Max Shut
Off Head
Flow Range Maintains constant
outlet pressure
IV CSV10301"Threaded30 PSI150 PSI90° F
32° C
1-25 gpmYes
IV CSV10401"Threaded40 PSI150 PSI90° F
32° C
1-25 gpmYes
IV CSV10501"Threaded50 PSI150 PSI90° F
32° C
1-25 gpmYes
IV CSV125401-1/4"Threaded40 PSI150 PSI90° F
32° C
2-50 gpmYes
IV CSV125501-1/4"Threaded50 PSI150 PSI90° F
32° C
2-50 gpmYes
IV CSV125601-1/4"Threaded60 PSI150 PSI90° F
32° C
2-50 gpmYes

The CYCLE STOP VALVE models CSV1/1.25 are patented pump control valves that automatically adjust pump output to match variable flow requirements. Downstream of the CSV1 and CSV1.25, pressure remains constant as long as demand on the system is between 1 and 25 gpm for the 1” and 2-50 gpm for the 1 1/4”. As flow rates vary, the valve inside the CSV1 moves closer to or farther away from the valve seat. This enables the pressure downstream of the CSV1/1.25 to remain constant regardless of flow. 

When there is no longer any demand on the system, the pressure begins to rise and the valve is pressed against the valve seat. The non-closing seat is designed to allow flow of approximately 1 gpm. As flow continues past the seat, 1 gpm begins to enter the pressure tank placed downstream of the CSV1/1.25. As the pressure tank slowly fills, the system pressure begins to rise to pressure switch shut off pressure. Pressure switch shut off pressure must always be set higher than the pressure regulated by the CSV1/1.25. Maximum pump shut off pressure cannot be higher than 150 PSI and pressure differential cannot be more than 125 PSI.

Regardless of tank size, as the tank fills, the pressure downstream of the CSV1/1.25 will slowly rise to the pressure switch shut off point and the pump will be shut off. As flow is again demanded from the system, the pressure tank will empty and the pressure switch will start the pump.

This valve eliminates water hammer in your system when start pressure and valve pressure are the same. The CSV1/1.25 is recommended for potable water systems and does not tolerate bacteria, algae, or sand abrasion. It is very important that this model not be put in a bind as it will bend in the middle and begin to squirt water until it is straightened back up.

Over time, (how long depends on water quality) the CSV1/1.25 can begin to vent water to atmosphere. (The valve will not leak when the pump is not running as the weep is a function of the valve actuating and not a leak) The CSV1/1.25 valve will function correctly whether it is venting air or water. If this “weeping” is not acceptable for your application, * the CSV1 should be installed in the well casing using the CSC1 or CSV1.25. An alternative model for most of the same applications would be the CSV1W/1Z. The CSV1W/1Z better tolerate bacteria, algae, and abrasives and do not vent water to atmosphere.

* With optional retainer coupling, the CSV1/1.25 is capable of supporting weight of up to 500 pounds making installation possible inside the well casing below well seals, pitless adapters, and in the well tanks. The CSV1/1.25 should not be submerged unless the vent is enlarged. Please specify on order.

Note: In multiple pump applications, never share a CSV with multiple pumps. Each pump must have its own valve. 

What are Cycle Stop Valves?

The Cycle Stop Valve is a patented pump control valve that makes a variable flow, constant pressure pump out of most standard, constant speed pumps.

Installed between the pump and your water system, the Cycle Stop Valve(CSV) automatically chokes back the output of a pump to match the usersdemand for water.

As the gallons per minute decrease, the amperage draw decreases as well because it is the weight of the water that determines the horse power or amperage needed, not the pressure.

The CSV maintains a constant pressure for the water user when demand iswithin the recommended range for the valve model being used.

It is completely mechanical and pressure actuated. No electricity required. Constant speed pumps are now capable of providing constant pressure in variable demand situations without expensive controls, huge pressure tanks, or water towers. Pumps equipped with a CSV can operate safely from as low as 1 gpm to as much as the pump can produce.

The CSV stops pump cycling, eliminates water hammer, extends pump life, andreduces energy costs compared to a system allowed to cycle off and on excessively when demand varies.

Back Pressure?

As counter intuitive as it may seem, increasing back pressure does not make pumps work harder. Onehorse power is the measure of power it takes to lift 33,000 pounds of weight (or 3,750 gallons) one foot in oneminute. Gallons and weight are the same thing to the pump. If flow from the pump is restricted with a valve,back pressure will increase. As back pressure increases, gallons or weight decreases. As the weight or gallonsof water being lifted by the pump decreases, so does power consumption, amps, or horse power. Excess backpressure is a free by-product of horsepower. Back pressure makes pumps pull less amperage, not more. Lessamperage means motors run cooler, use less electricity, and last longer.

Minimum Flow?

While Cycle Stop Valves will increase back pressure on pumps when needed, they will never let theback pressure increase to complete shut off head. The Cycle Stop Valve can never completely close. There isalways water flowing through the valve even when in its fully closed position. This flow is derived from theminimum cooling requirements of the pump and motor. Large submersible pumps can operate on much smallerflows than .5 feet per second. Flow charts for motors running at FULL LOAD AMPERAGE are not relevant formotors pulling an average 60% of full load. As back pressure increases until the pump is only pumping minimumflow, amperage decreases, derating the motor. When pulling only 50 to 60% of full load, the derated motorcan safely pump hot water up to 140 degrees according to the charts. If a derated motor can safely pump anyamount of 140 degree water, then a tiny amount of cool water (86 degrees or less) will easily prevent themotor from overheating. Minimum cooling charts for derated motors have not been made available by themotor manufactures. Years of experience has proven many times over that motors such as a 50 HP sub willdrop from 77 amps to about 40 amps when the pump is restricted to 5 gpm flow. This 5 gpm flow of 70degree water going past the motor will increase in temperature to 78 degrees. Seventy eight degrees is noteven close to 131 degree water that the charts say can safely cool a 50 HP motor when derated by 40%. Fullspeed turbines and centrifugal pumps can operate at even lower minimum flows as their motors are cooled byair. Motor and cooling fan are still spinning at full RPM, which will keep a motor that is only pulling 60% of fullload amps very cool.

Resting Pumps and Motors?

Pumps and motors are designed for continuous operation and do not need to rest. This means theywill last longer if they run continuously than if they “cycle” off and on. Motors that are coasting along at lowamperage 24 hours a day will use less electricity than the same motor pulling full load and cycling on and offevery 10 minutes or so. Most motor and pump failures occur during start up. Starting current can be sixtimes normal running amperage. Start up tests every component of the pump and motor. Windings, bearings,shafts, impellers, splines, couplings, panels, even the generator at the power company are all tested each timea pump starts. All of these problems go away once the motor is up and running. Common sense would suggestthat the fewer times it starts and stops, the longer a motor and pump will last.

Soft Start Equipment?

Some electric companies require soft starts on larger horse power systems. Cycle Stop Valves willcompletely eliminate water hammer with or without electrical soft start equipment and will also provide thesame no load start up comparable to any electrical soft start equipment. This will reduce the electric bill if ademand charge is included.


Restricting the discharge from a pump with any valve will decrease the NPSH required.The NPSH available will increase as the flow rate decreases. Increasing the NPSHA and/or decreasingthe NPSHR reduces the chance of cavitation. Recirculating water from the outlet to theinlet of an impeller can occur at low flow. The 5 GPM bypass exiting the Cycle Stop Valve will keepthis recirculating from heating up the pump. Cavitation like wear can occur if the pump chosen hasa recirculating problem such as with a loose-fitting wear ring. Pumps that are made of materialswith a high tensile strength are more resistant to wear from cavitation. When equipped with anadditional pressure sustain pilot the Cycle Stop Valve can also control cavitation at high flow ratesby limiting the maximum flow from the pump.

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