How to Size a Valve Actuator for HVAC or Industrial Use: A Complete Guide

Properly sizing a valve actuator is critical for ensuring reliable performance in both HVAC and industrial applications. An undersized actuator can lead to valve failure, reduced efficiency, and increased maintenance. An oversized actuator can drive up costs and energy consumption unnecessarily.

At Enolgas USA, we specialize in premium-quality electric and pneumatic valve actuators

that are designed to deliver optimal control and durability. This guide walks you through the

essential steps to correctly size a valve actuator for your application.

1. Understand the Type of Valve

Different valves require different actuator torque outputs. Common types include:

• Ball valves – Require higher breakaway torque due to tight sealing.

• Butterfly valves – Typically need lower torque but vary with seat material and size.

• Plug valves – May require high torque, especially in full-port designs.

• Globe valves – Often need linear actuators instead of rotary.

Tip: Always match the actuator to the valve type. For example, our Enolgas electric ball

valve actuators are ideal for precise HVAC control.

ILLUSTRATION FROM WORLD OF ENGINEERING

2. Determine Valve Size and Media Pressure

Actuator torque depends significantly on the valve size (in inches) and the media pressure (psi/ bar). Larger valves or higher pressures increase the torque required to operate the valve.

Use this general formula:

Required Torque (Nm) = Valve Torque x Safety Factor

• Valve torque is usually provided by the valve manufacturer (in datasheets).

• Safety factors typically range from 1.25 to 1.5 for normal conditions.

Calculation of Required Torque for Valves Using Safety Factor Formula.

3. Identify the Media Type

Identify various media types with clear icons and labels for steam, water, air, and gas on a blue gradient background.

The fluid type—whether it’s steam, water, air, oil, or gas—affects torque. For example:

• Steam and viscous liquids often require more torque.

• Dry gases may require less torque, but sealing becomes more critical.

In HVAC systems, consider chilled water, hot water, glycol, or steam lines when selecting

actuators.

4. Consider Duty Cycle and Frequency of Operation

• HVAC actuators might cycle frequently for temperature or flow regulation.

• Industrial actuators may operate infrequently but under high stress.

Choose actuators rated for the appropriate duty cycle:

• On/off control

• Modulating control (proportional)

• Fail-safe return (spring return or capacitor-driven)

Enolgas USA offers modulating and on/off valve actuators with adjustable torque settings

and thermal protection.

5. Choose Between Electric or Pneumatic Actuation

Electric Valve Actuators

• Preferred for HVAC systems and locations without compressed air.

• Easy to install and control via building automation systems.

• Offer better precision for modulating applications.

Pneumatic Valve Actuators

• Ideal for fast action in industrial environments.

• Lower upfront cost but require an air supply and maintenance.

We offer both electric and pneumatic valve actuators, compatible with ball and butterfly

valves across and industrial setups.

Comparison of electric and pneumatic actuators by Enolgas, highlighting their distinct designs and applications for industrial use.

6. Account for Environmental Conditions

• Indoor vs. outdoor installations

• Temperature extremes (hot boiler rooms or outdoor freezing conditions)

• Hazardous or corrosive environments

Look for:

• IP-rated enclosures for water and dust protection

• Corrosion-resistant housings (aluminum or stainless steel)

• Explosion-proof options for hazardous areas

Enolgas USA actuators are available in NEMA and IP-rated enclosures with various

material options for durability.

7. Use a Manufacturer Sizing Chart or Calculator

To find the proper size, consult with our technical team. Please provide the following:

• Valve type and size

• Line pressure

• Media

• Actuation method (electric or pneumatic)

• Fail-safe requirements

• Modulation or on/off control

Our team of expert can be contacted at sales@enolgasusa.com or at 754-205-7903