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Brass pneumatic thermostat valve two-way body spring return actuator

SIEMENS

SIEMENS 257-02041 pneumatic thermostat 4.00 Cv

SKU CH-D07R-B0H9B

A pneumatic control valve for chilled or hot water systems with a 4.00 Cv rating and spring-return actuator

  • TypeLearning Thermostats
  • Precise flow control with 4.00 Cv rating
  • Reliable spring-return actuator for fail-safe operation
  • Durable brass body handles up to 250 °F fluid
  • Operates on 3 to 8 psi pneumatic control pressure
  • Two-way valve design for chilled or hot water systems

SIEMENS 257-02041 Pneumatic Thermostat

The SIEMENS 257-02041 is a pneumatic thermostat designed for chilled and hot water control in HVAC systems. It operates with a brass two-way valve body and a spring-return pneumatic actuator. The unit provides a 4.00 Cv flow coefficient and functions within a 3 to 8 psi control pressure range. It is built for new installations or replacements in commercial mechanical rooms.

Replaces Worn Pneumatic Valve Assemblies

This thermostat replaces existing pneumatic control valves that have degraded spring returns, leaking brass bodies, or inaccurate pressure response. The upgrade is worth it when the current valve fails to maintain the 35 to 250 degrees F fluid temperature range or exceeds the 45 psi close-off pressure limit. It restores precise flow control without converting to electronic actuation.

Verify Piping Pressure And Temperature Ratings

Confirm the system fluid temperature stays between 35 and 250 degrees F and that operating pressure does not exceed 45 psi close-off. Ensure the control air supply can deliver a stable 3 to 8 psi signal to the actuator. The two-way body pattern must match the existing piping layout and the brass material must be compatible with the fluid chemistry.

Highlights

  • Precise flow control with 4.00 Cv rating
  • Reliable spring-return actuator for fail-safe operation
  • Durable brass body handles up to 250 °F fluid
  • Operates on 3 to 8 psi pneumatic control pressure
  • Two-way valve design for chilled or hot water systems

Specifications

BrandSIEMENS
TypeLearning Thermostats

Questions about this item

What pipe connection does the 4.00 Cv valve body use?

The brass two-way body has fixed female connections for direct piping.

How do you set the 3 to 8 psi actuator range during installation?

Apply control pressure within the 3 to 8 psi span and verify spring return action before commissioning.

When should the actuator diaphragm be inspected on chilled water at 250 Degrees F?

Plan diaphragm checks annually when fluid temperature regularly approaches the 250 Degrees F limit.

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