If you’re looking to control and regulate gas or fluid pressure in your plumbing or industrial system, you may be weighing the pros and cons of a cycle stop valve versus a pressure regulator.
Though they serve similar functions, there are some key differences between these two devices that are important to understand.
A Brief Comparison Table
| Feature | Cycle Stop Valve | Pressure Regulator |
| Flow Pattern | Intermittent, cycling on/off | Continuous, steady flow |
| Pressure Control | No active regulation | Precise pressure regulation |
| Installation | In fluid flow path | Upstream of equipment |
| Applications | Timed, cycling flow | Protect equipment, steady pressure |
| Operation | Self-actuated timing mechanism | Self-relieving diaphragm/spring |
| Cost | Inexpensive | Moderate cost |
| Maintenance | Routine inspection | Occasional diaphragm replacements |
What is a Cycle Stop Valve?
A cycle stop valve is a type of automatic valve designed to interrupt the flow of gas or liquid on a cyclical basis.
It works by opening and closing repeatedly at preset intervals to allow flow for a period of time, then stop it for a period of time.
The opening and closing is controlled by an internal timing mechanism.
This creates an intermittent on/off cycle of flow rather than a constant stream.
Cycle stop valves are often used in irrigation, chemical treatment, and other industrial applications where an intermittent supply of fluid is desirable.
Some key features of cycle stop valves include:
- Automatically cycles flow on and off at preset intervals
- Available for gas, liquid, steam, and air systems
- Interval duration and frequency are adjustable
- Requires no external power source to operate
- Typically compact and lightweight for easy installation
Cycle stop valves help provide greater control over fluid flow. They are useful when you need to pulse or alternate the flow at timed intervals. This can help prevent over-pressurization, regulate chemical treatments, and improve efficiency in many applications.
What Is A Pressure Regulator?
A pressure regulator is a valve designed to control, maintain, or reduce the pressure of a gas or liquid in a system. Pressure regulators work by opening more or less in response to the downstream pressure to keep it at the desired set point.
Key features of pressure regulators include:
- Maintains steady outlet pressure regardless of inlet pressure
- Wide range of pressure control settings available
- Ideal for protecting equipment from excess pressure
- Available for liquid, gas, steam, and air
- Self-operating to regulate pressure automatically
- Often include gauges, valves, and other features
Pressure regulators are used anywhere that consistent, stable pressure control is required. They help provide smooth, uninterrupted flow at the specified pressure. This prevents damage from surges and maintains optimal operating conditions.
Key Differences Between Cycle Stop Valve And Pressure Regulator
While both cycle stop valves and pressure regulators help control fluid flow, there are some important ways these two devices differ:
Flow Pattern
- Cycle stop valves provide intermittent, cycling flow on and off at intervals
- Pressure regulators maintain steady, continuous flow
Pressure Control
- Cycle stop valves do not actively regulate pressure
- Pressure regulators hold a very precise outlet pressure set point
Installation
- Cycle stop valves are positioned directly in the flow path
- Pressure regulators are installed after other components and upstream of equipment needing protection
Applications
- Cycle stop valves are ideal for applications needing timed, cycling flow
- Pressure regulators excel at maintaining exact pressure requirements
Some key considerations when choosing between these two types of valves:
- If you need to interrupt flow on a schedule, a cycle stop valve is appropriate
- To protect equipment and maintain precise pressure, a regulator is preferred
- Cycle stop valves provide basic on/off control, not active pressure regulation
- Pressure regulators require continuous upstream flow to function
Understanding these differences allows you to select the best valve for your particular plumbing, industrial, or irrigation application.
Pros and Cons of Cycle Stop Valves
Pros
- Provide automatic, intermittent flow cycles without need for external power
- Compact, easy to install directly in piping systems
- Flow cycle frequency and duration are adjustable
- No electricity required for operation
- Prevent over-pressurization by interrupting flow
- Inexpensive compared to other automatic valves
Cons
- Lack active pressure regulation ability
- Can cause water hammer if downstream pressure builds up
- Limited adjustment range on cycle frequency and duration
- Flow pulsations may not be suitable for some applications
- No flow when in closed cycle position
Pros and Cons of Pressure Regulators
Pros
- Maintain very precise, consistent outlet pressure
- Protect equipment by preventing pressure spikes or surges
- Wide range of adjustable pressure settings available
- Continue providing smooth flow even with fluctuating inlet pressure
- Prevent damage from excess pressure in plumbing or equipment
- Compact and suitable for gases, liquids, steam, and air
Cons
- Require continuous upstream flow to function properly
- More expensive than basic stop valves
- Require power/electricity on some advanced electronic models
- Subject to wear over time requiring inspection and maintenance
- Generally not capable of providing intermittent cycling flow
Typical Applications
Cycle stop valves are commonly used in:
- Irrigation systems – to cycle sprinkler zones on and off
- Chemical/water treatment – to pulse chemical injections
- Hydraulic power packs – to provide intermittent pressure
- Compressor blowdown cycles
- Hot water cycling to manage scale buildup
- Level control of tanks by cycling inlet flow
Pressure regulators are ideal for applications like:
- Compressed air tools and equipment
- Controlling pump discharge pressure
- Protecting downstream plumbing fixtures
- Maintaining gas line pressures
- Managing pressure between compressor stages
- Providing precise water pressure to appliances
- Reducing steam pressures to safe levels
Choosing the right valve comes down to matching the device features to your particular needs. Understanding the capabilities of cycle stop valves vs. pressure regulators allows you to make an informed selection.
Cycle Stop Valve Installation Tips
Proper installation helps ensure cycle stop valves function as intended:
- Position horizontally to allow grit to fall out when valve closes
- Install downstream of filters and upstream of equipment needing protection
- Allow straight pipe runs before and after the valve
- Check manufacturer instructions for required upstream diameters
- Support valve to prevent side loading and pipe strain
- Install a resilient seat to prevent water hammer when valve closes
- Locate valve for easy access and maintenance
Pressure Regulator Installation Tips
To get the best performance from your pressure regulator:
- Install vertically with flow going upward
- Position after any control valves and as close to equipment as possible
- Allow adequate clearance above and around regulator
- Install a strainer upstream to prevent debris from damaging seat
- Include a pressure relief valve to protect from excess pressure
- Install gauges before and after to monitor inlet/outlet pressures
- Provide unions and isolation valves to ease maintenance
Proper installation helps pressure regulators maintain critical flow parameters and equipment protection.
Frequently Asked Questions (FAQ)
No, cycle stop valves and pressure reducing valves are distinctly different. Cycle stop valves provide timed, intermittent flow cycles. Pressure reducing valves maintain a steady preset outlet pressure.
Valves like cycle stops simply start and stop flow. Pressure regulators employ a self-contained mechanism that reacts to downstream pressure to maintain a steady delivery pressure.
The purpose is to provide repetitive on/off flow cycles without need for external power. This intermittent cycling is useful for applications like irrigation, chemical injection, compressor control, and more.
Cycle stop valves are best installed horizontally directly in the flow path upstream of the equipment or operation where cycling flow is desired. Proper support and pipe alignment helps prevent valve damage.
Conclusion
In summary, while both valves are used to control fluid flow, cycle stop valves provide intermittent cycling operation whereas pressure regulators maintain a fixed delivery pressure.
Understanding this key difference allows you to select the best valve type for your particular application needs. When properly installed, they can help optimize your industrial or plumbing system performance and reliability.
