The ASCO™ Series 221 Slow Closing Water Solenoid Valve is engineered to deliver dependable water flow control while minimizing damaging pressure surges. Designed with a specialized slow-closing mechanism, this valve helps prevent water hammer and extends the life of piping, pumps, and system components.
Ideal for commercial and industrial water applications, the ASCO™ 221 combines high flow capacity, flexible electrical options, and easy serviceability. The result is a robust solenoid valve solution that protects equipment, improves process reliability, and simplifies maintenance.
Common applications include:
- Industrial laundries
- Sterilizers and autoclaves
- Injection molding equipment
- Commercial water systems
- Process heating systems
With multiple pipe sizes, electrical configurations, and flow capacities available, the ASCO 221 provides a versatile solution for water control in demanding environments.
Features
221 Slow-Closing Water Solenoid Valve Features
Slow-Closing Design Reduces Water Hammer
A built-in damping mechanism slows the valve’s closing motion, helping prevent sudden pressure spikes that can damage pipes, fittings, and instrumentation.
Protects System Components
By minimizing hydraulic shock, the valve helps extend the life of pumps, filters, gauges, and piping systems.
Handles Hot or Cold Water
The ASCO™ 221 is designed to handle a wide range of water temperatures, including hot water service up to approximately 210°F (100°C) at differential pressures up to 150 psi.
Flexible Electrical Options
Available in a wide selection of AC and DC voltages, making integration with existing control systems straightforward.
Multiple Pipe Sizes Available
Offered in pipe sizes from 3/8 in. up to 2-1/2 in., allowing the valve to accommodate a wide variety of flow requirements.
Design
How the ASCO™ 221 Prevents Water Hammer
Water hammer occurs when fluid flow stops suddenly, creating a pressure surge that travels through the piping system. These pressure spikes can lead to:
- Pipe vibration and noise
- Damaged seals and fittings
- Premature pump wear
- System downtime
The ASCO™ 221 addresses this issue with a controlled, slow-closing action. Instead of shutting instantly, the valve closes gradually using an internal snubber mechanism. This controlled closure reduces the velocity change in the fluid column, limiting the pressure spike that normally occurs when valves close quickly.
In many installations, this design can eliminate the need for separate surge suppressors or additional water hammer protection devices.
Specifications
221 Slow-Closing Water Solenoid Valve Specifications
Valve Type: 2-way solenoid valve
Operation: Pilot operated
Media: Water
Body Material: Brass
Available Functions:
- Normally Closed (NC)
- Normally Open (NO)
Pipe Sizes: 3/8 in. to 2-1/2 in. NPT
Pressure Range: Vacuum to approximately 150 psi differential
Temperature Range: Up to 210°F (100°C) for hot water service
Voltage Options: Multiple AC and DC voltages available
Flow Capacity: Cv values ranging from approximately 2.0 to over 14 depending on valve size.
Applications
221 Slow-Closing Water Solenoid Valve Applications
The ASCO™ 221 Slow-Closing Water Solenoid Valve is widely used in systems where reliable water flow control and surge protection are critical.
Industrial Laundries
Controls hot water flow to washers and process equipment while preventing pipe shock in high-cycle systems.
Sterilizers & Autoclaves
Provides reliable water supply control in equipment operating with elevated temperatures.
Injection Molding Equipment
Used for cooling water circuits where frequent cycling requires durable valves.
Commercial Water Systems
Ideal for facilities where protecting plumbing infrastructure from water hammer is essential.
Process Heating Systems
Supports hot water distribution systems used in manufacturing and industrial processing.
Q & A
221 Slow-Closing Water Solenoid Valve Q & A
A slow-closing solenoid valve is designed to gradually stop water flow instead of shutting instantly. This prevents water hammer, a pressure surge that occurs when flow stops abruptly. By reducing hydraulic shock, slow-closing valves help protect pipes, pumps, and instrumentation from damage.
The ASCO™ 221 is ideal when:
- Water hammer is a concern
- Large pipe sizes or high flow rates are present
- Equipment cycles frequently
- System reliability and longevity are critical
In these situations, the slow-closing feature can significantly reduce maintenance and downtime.
Typical installations include:
- Industrial laundry equipment
- Autoclaves and sterilizers
- Injection molding cooling circuits
- Commercial water distribution systems
- Process heating systems
These applications benefit from the valve’s high flow capacity and surge-reducing design.
The ASCO™ 221 series is available in pipe sizes from 3/8 inch to 2-1/2 inches and supports a broad range of AC and DC coil voltages, allowing it to integrate with most industrial control systems.
Yes. The valve is designed for both hot and cold water service, with hot water ratings up to approximately 210°F (100°C) at differential pressures up to 150 psi, making it suitable for demanding commercial and industrial systems.
Download ASCO™ Slow-Closing Solenoid Valves Datasheet
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