There are several products on the market that try to accomplish the same task as the non-closing design of a Cycle Stop Valve. Many valves are available with fully closing valve seats using a small hole or bypass tube to allow for cooling of the pump or motor and for filling of the pressure tank. The small hole or bypass tube can become clogged with debris or grow closed same as the holes in your shower head causing overheating and destruction of the pump or motor. These fully closing type valves can also cause water hammer or pressure waves when the valve closes fully or when it pops open from the closed position. Some valves use speed controls to reduce the pressure waves by slowing the opening and closing speed of the valve. These speed controls can keep the valve from reacting fast enough to keep up with changes in the field. If the control valve does not react as fast as the flow rate in the field changes, the pump can be bounced on and off several times while the valve is catching up. Franklin Electric or Jacuzzi, now called Franklin Pump Company made the Aqua Genie 400 in the past. Flexcon industries had a valve called a Smart Tee or Smart Tank. Red Jacket Pumps used to make a valve called the Hydroservant. The new Hydroservant, which will be discussed later, is now a variable speed drive not a valve. Danfoss Flomatic makes a fully closing control valve which is called a Cyclegard and is in no way related to the non-closing Cycle Stop Valve.
Danfoss Flomatic as well as Cla-Val, Watts ACV, Bermad, OCV, Dorot, Raphael, Netafim, Zurn-Wilkins, and Senninger, all make check valves and fully closing control valves that do not have the same control characteristics as a Cycle Stop Valve.
Variable Frequency Drives or (VFD) are also known as Variable Speed Drives (VSD), Adjustable Speed Drives (ASD), Variable Speed Pumps (VSP), Variable Speed Controllers (VSC), Adjustable Frequency Drive (AFD), Frequency Inverters, Inverters, or just Drives. These electronic devices will reduce the RPM of a motor and pump to try and match pump output with the demand. Head is reduced by the square of the RPM which limits the usefulness of these devices. Claims of energy savings are greatly exaggerated as the pump is not able to be slowed enough to save energy. Slowing the RPM by more than 10% reduces the head produced to a point where the pump is no longer moving any fluid. Although we may expect beneficial technology to be electronic, this is not always the case. The same job and energy efficiency can be accomplished without the use of electronics buy using a Cycle Stop Valve, which makes a water supply system simpler and more dependable. Many companies make drives such as the Franklin CP Water, Franklin Monodrive, Grundos SQE, ITT Goulds, Goulds Aquavar, Goulds Aquaboost, Goulds Hydrovar, Goulds Technovar, Goulds Pump Smart, Red Jacket Hydroservant, Pentair Pressure Controls or Pressure Central (PPC's) (BPC), ABB Drives, Allen Bradley Drives, Squared D Drives, Altivar, Danfoss Drives and others. Packaged pump systems using Drives are also made by Flotronics, Watertronics, Syncroflo, National Pump VFD, Tigerflow, Grundfos Boosterpac, Peerless package systems, Pacoflo, Paco Miniflo, Rainbird Pump Station and others.
MagnaDrive and pumps with automatic transmissions have variable speed characteristics without many of the negative side effects. The motor is spinning at normal speed and running on standard voltage and frequency while the pump is slowed to match the usage. Transmissions waste or burn energy. Magnetic couplings must be controlled with electronics and pressure transducers, which can cause problems. Magnetic couplings can be expensive and require a certain amount of space, which restricts their use for installations with limited space such as submersible pumps. As with the Variable Frequency Drives, these devices also slow the RPM of the pump, which causes head to be reduced by the square of the speed, limiting their usefulness on pumping systems that require a certain head to operate correctly.
Other types of devices such as Mascontrol or Prescontrol, Davey Pressure Booster Systems ,and Franklin Pump Aqua Genie 80, are flow switches and time delay. These devices turn the pump off when there is no flow and restart the pump at a lower pressure. Unless used with a pressure reducing valve these devices have no control over the pressure, meaning full pump pressure may be seen in the distribution system. Small flow rates or leaks in the system can cause the pump to cycle on and off rapidly. Small centrifugal and jet pumps may be able to tolerate this cycling abuse for a short while but larger pumps and submersibles will not last very long when cycling rapidly.
Systems using a pressure tank and pressure switch as the only controls such as the Amtrol Pressuriser, cycle according to the pressure tank size. Larger tanks reduce the number of cycles but do not stop destructive pump cycling. In systems that pump fairly cool and fairly clean water, nothing beats the simplicity and reliability of a Cycle Stop Valve.
The Cycle Sensor is a motor protector that was designed to work with a Cycle Stop Valve. This device looks for dry run conditions and sees rapid cycling as a fault and shuts the pump off. The Cycle Sensor has a fully adjustable underload setting which can be superior to many other protectors on the market such as Symcom, Pumptec, Coyote, and The Protector SPS, and Franklins Sub Monitor.