How do I select between normally open and normally closed valve configurations?

For heating applications where the valve must close as temperature rises, select a normally open valve. For cooling applications where the valve must open as temperature rises, select a normally closed valve.

What determines the correct valve size for my application?

Valve sizing depends on inlet pressure (P1), outlet pressure (P2), differential pressure, and required flowrate. Use the manufacturer's sizing charts for steam or water to determine the appropriate Kvs value and corresponding valve size.

Can these valves handle high differential pressure across the valve?

Yes, for applications with high differential pressure, select valves with balanced bellows. This ensures the actuator can overcome plug forces during closing. Refer to the valve selection tables for balanced options.

What ancillaries are required for installation?

Typical ancillaries include sensor pockets (stainless steel recommended), mounting brackets, and appropriate capillary tube lengths based on sensor location relative to the valve.

Do these valves require external power or pneumatic supply?

No, Spirax Sarco self-acting temperature control valves operate entirely on thermal energy from the process. The sensor-capillary-actuator system is self-contained and requires no electrical or pneumatic connections.

SPIRAX SARCO · CONTROL VALVES

Spirax Sarco 2-Port Self-Acting Temperature Control Valves for Heating and Cooling Applications

Name: Spirax Sarco 2-Port Self-Acting Temperature Control Valves for Heating and Cooling Applications
Brand: Spirax Sarco

Spirax Sarco 2-port self-acting temperature control valves for steam and water heating/cooling systems. Available at PC Engineering India.

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Spirax Sarco 2-Port Self-Acting Temperature Control Valve Selection Guide

Overview

Spirax Sarco 2-port self-acting temperature control valves are designed for precise, autonomous temperature regulation in heating and cooling applications. These valves operate without external power, using a thermostatic sensor and capillary system to modulate flow based on process temperature changes.

For heating applications, normally open valves close progressively as temperature rises. For cooling applications, normally closed valves open as temperature increases. This makes them suitable for controlling steam or water flow in heat exchangers, storage tanks, jacketed vessels, and HVAC systems across industrial plants.

The control system comprises a sensor, capillary tube, and actuator, allowing remote temperature sensing with adjustable control ranges. Multiple valve types (BX, BM, BMF, SB, KA, KB, KC, NS series) are available to match specific Kvs requirements, pressure ratings, and connection standards.

Key Features

Self-acting operation — no external power or compressed air required
Available in normally open (heating) and normally closed (cooling) configurations
Wide range of Kvs values from 0.38 to 94 for precise flow matching
Compatible with steam and water systems
Multiple body materials: gunmetal, cast iron, and cast carbon steel
Screwed or flanged end connections (EN 1092 PN40 available)
Balanced bellows option for high differential pressure applications
Adjustable temperature control ranges via interchangeable control systems
Capillary tube lengths available for remote sensor mounting

Specifications

Parameter	Value
Valve Sizes	DN15 to DN80
Kvs Range	0.38 to 94
Valve Types	BX, BM, BMF, SB, KA, KB, KC, NS series
Body Materials	Gunmetal, Cast Iron, Cast Carbon Steel
End Connections	Screwed or Flanged (EN 1092 PN40)
Media	Steam, Water
Configuration	Normally Open (heating), Normally Closed (cooling)
Control System	Sensor + Capillary Tube + Actuator
Capillary Length	Multiple lengths available
Standards	EN 1092 (flanged connections)

Applications

- Steam-heated heat exchangers and calorifiers - Hot water storage tank temperature control - Jacketed vessel heating/cooling in process industries - HVAC heating and chilled water systems - Domestic hot water temperature regulation - Process heating in food, beverage, and pharmaceutical plants - Industrial cooling water circuits - Tank heating coils in chemical processing

Product Images

Valve Sizing Chart for Steam Heating Applications

Frequently Asked Questions

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