Kele Blog

Coming soon: More ways to find what you need on kele.com

Posted on by Kele Inc

Whether you’re using kele.com for research, estimating a project or ordering a replacement, finding the right part shouldn’t be a challenge. We’re expanding kele.com navigation to give you more ways to find the brands and products you rely on.

Did you know you’ve gained access to 8K+ new products this year, including expanded offerings from ASCO, United Electric and Honeywell? And there’s more to come.

What’s new in kele.com navigation

As our product selection grows, the kele.com menu is growing with it. Here’s what you’ll see:

  • Products: The products menu is still there, updated to group our expanded catalog, including some new category names.
  • Applications: Browse products by the system need such as Temperature Monitoring.
  • Brand: Go straight to the manufacturers you need, including Schneider Electric, Johnson Controls and Kele.

What stays the same

Your kele.com account access, order history and saved lists in project portal work just as they do today, and so does the way you place orders. You’ll also have the same customer service and technical support teams to help you find the right products and keep your projects moving.

Frequently asked questions

Why is Kele updating its website navigation?

As Kele’s selection grows, we’re updating kele.com navigation and adding more ways to browse based on your needs. Whether you need to find a specific item quickly, explore options for an application or see options from a specified brand, you’ll have a clearer view of everything we carry and more ways to find what you need.

Will I still be able to find the products I usually buy?

Yes. Every product you buy today will still be on kele.com. To make room for the expanded offering, we’ve updated and renamed many categories and grouped related products together, so some products will appear under new category names. If you’d like help finding something, our team is happy to walk you through it.

The examples below show where you’ll find most products in the new navigation:

Current category: Pressure Components

New product path: Sensors & Instrumentation → Sensors; Transmitters; Switches → (multiple Pressure options)

New application path: HVAC & Building Systems → Pressure Monitoring

Current category: Power Supplies

New product path: Power & Electrical Components → Power Supplies

Current category: Gas & Specialty Sensors

New product path: Sensors & Instrumentation → Sensors; Transmitters; Switches → (multiple gas options)

New application path: Gas Detection Systems → Carbon Dioxide Monitoring; Carbon Monoxide Monitoring; Multi-Gas Monitoring; Refrigerant Leak Monitoring

Current category: Power Monitoring & Protection

New product path: Power & Electrical Components → Power Monitors; Transformers; Surge Protectors

New application path: Energy & Power Monitoring → Power Monitoring; Surge Protection

Current category: Leak

New product path: Sensors & Instrumentation → Detectors → Leak Detectors

New application path: HVAC & Building Systems → Leak Detection

Will the way I purchase products change?

No. The purchasing process on kele.com will remain the same. You’ll be able to continue placing orders just as you do today.

Will Kele’s customer service and technical support change?

No. You’ll continue to have access to the same knowledgeable customer service and technical support teams you’ve come to rely on.

What if I need help finding a product after the update?

You can contact Kele’s customer service at 877.826.9045 for assistance and we’ll help you find it.

A new way to navigate. The same Kele commitment.

We’re looking forward to showing you more of what Kele offers. The updated navigation isn’t live yet, but we wanted to give you an early look at what’s coming. As our selection grows, you’ll have the same Kele team behind every order.

Kele. Automation Made Easier.

Control relay selection: Understanding voltage separation

Posted on by Kele Inc

Sponsored by Functional Devices

Relays play a simple but critical role in building automation: they allow one electrical circuit to control another. A low-voltage controller output can energize a relay coil, while the relay contacts switch a separate load circuit. That makes the relay an important interface between the building automation system and equipment operating at different voltages or current levels.

But selecting the right relay involves more than finding one with enough contacts. The available control signal, the load being switched, contact configuration and installation requirements all need to be considered. When control wiring and higher-voltage load wiring meet at the same device, how those connections are arranged can also become an important part of the selection.

Functional Devices RIB® and RIBT Pilot Series relays, available from Kele, provide two approaches to enclosed relay installation. Both offer prepackaged relay solutions for control applications, while the RIBT Series is specifically designed to provide physically separate entrances for the relay coil and contact wiring.


Functional Devices RIB enclosed relay

“The relay is the interface between the control system and the equipment it controls.”

Start with what the relay needs to do

A relay creates an electrically operated switching point between the control circuit and the circuit being controlled. On the control side, a BAS output energizes the relay coil. When the coil is energized, the relay changes the state of its contacts. Those contacts can then switch another circuit without requiring the BAS controller output to directly carry the load.

For example, a controller operating at 24 VAC may need to command equipment on a higher-voltage circuit. Rather than asking the controller output to switch that load directly, the controller energizes the relay coil. The relay contacts handle the switching on the load side.

That basic arrangement makes several relay specifications important:

 

Selection consideration Why it matters
Coil voltage Must be compatible with the signal available to energize the relay
Contact configuration Determines how many circuits and normally open/closed functions can be controlled
Contact rating Determines the type and size of load the contacts can safely switch
Coil current Determines how much current the controller or control transformer must provide
Wiring arrangement Determines how control-side and contact-side wiring enter and connect to the device
Override or HOA switch Can provide local control for commissioning, service or troubleshooting
Enclosure Must suit the installation environment

 

Looking at these requirements together is more useful than selecting a relay based on voltage or amperage alone.

Match the coil to the control signal

Before a relay can switch anything, its coil has to operate reliably from the available control signal. The coil voltage tells you what voltage is required to energize the relay. In BAS applications, 24 VAC and 24 VDC are common control voltages, but other voltages may be encountered depending on the controller and application.

Coil current matters too. The BAS output or control transformer supplying the coil must be capable of providing the current the relay requires. If the control source cannot reliably energize the coil, the relay may not operate as intended. Universal coil options can simplify this part of relay selection. For example, the Functional Devices RIBU1C accepts 10-30 VAC/DC or 120 VAC, allowing the same relay model to accommodate several common control voltages.

This can be particularly useful on projects where control voltages vary from one application to another, reducing the number of voltage-specific relay models that need to be specified, stocked or carried for service.

“The coil has to operate reliably from the available control signal.”

Then look at what the contacts are switching

The coil side tells you how the relay will be controlled. The contact side determines what it can control. Start with the contact configuration. A single-pole, double-throw, or SPDT, relay provides a common contact that can switch between normally open and normally closed contacts. Other applications may require multiple poles or multiple relays when more than one circuit needs to be switched.

Next, check the contact rating against the actual load. Resistive, motor, pilot-duty and other loads can have different ratings even on the same relay. A relay rated for a particular resistive amperage should not automatically be assumed capable of switching every load at that amperage.

For larger loads, the relay may instead be used to pilot a properly sized contactor. In that arrangement, the BAS energizes the relay, the relay controls the contactor coil and the contactor switches the larger load. The important point is to select the relay based on both sides of the application: what will energize it and what it will switch.

When voltage separation becomes part of the decision

The electrical isolation provided by a relay and the physical arrangement of its wiring are related, but they are not the same thing. The relay itself allows the coil circuit to control electrically isolated contacts. But an installation may also call for physical separation between the wiring connected to those two sides.

This becomes particularly relevant when low-voltage control wiring and higher-voltage contact wiring terminate at the same relay location. The applicable wiring method and separation requirements depend on the installation, conductors, equipment and governing codes, so they should be evaluated as part of the design rather than after the relay has been installed. This is also where the physical construction of the relay can make installation easier.

Standard RIB or RIBT?

Functional Devices’ standard RIB Pilot Series packages the relay in a compact enclosure with pre-wired, color-coded leads. The design eliminates many of the separate components associated with building a relay assembly from individual parts. The RIBT Series is designed specifically for applications where physical separation of the coil and contact wiring is needed. Functional Devices refers to the RIBT line as its High/Low Voltage Separation Series.

In a RIBT relay, the contact wires exit the housing through the NPT nipple. The coil-drive wiring enters separately through openings in the removable cover and terminates on screw terminals within a separate wiring compartment.

That construction creates distinct wiring entrances for the control and contact sides rather than bringing both sets of conductors through the same entrance.

The choice is therefore not simply about whether the relay is switching two different voltages. The question is whether the installation calls for the additional physical wiring separation provided by the RIBT design.

 

Installation consideration Standard RIB Pilot Series RIBT Pilot Series
Enclosed relay Yes Yes
Prepackaged design Yes Yes
Coil and contact functions electrically isolated Yes Yes
Pre-wired/color-coded leads Yes Contact leads are pre-wired
Separate entrance for coil wiring No Yes
Coil screw terminals in separate compartment No Yes
Designed specifically for physical high/low-voltage wiring separation No Yes
Typical fit General enclosed relay applications Applications requiring separate entrances for control and contact wiring

Don’t overlook local override and status

Relay selection can also affect how easily a system can be commissioned and serviced. An LED status indicator provides a quick visual indication of relay status, which can be useful when troubleshooting whether the control signal is reaching the relay.

Some RIB and RIBT Pilot Series models also provide override switch options. Depending on the model, this can allow technicians to command the relay locally rather than relying solely on the BAS signal during commissioning or troubleshooting. That distinction is important: relay status tells you what the relay is doing, but it does not necessarily prove that the controlled equipment is operating. If the BAS needs confirmation that a fan, pump or other load is actually running, additional status feedback, such as a current sensor or equipment auxiliary contact, may be required.

Consider the installation environment

The enclosure is another part of relay selection that should match the installation. A standard enclosure may be appropriate for a protected indoor location, while applications exposed to moisture, dust or other environmental conditions may require a higher enclosure rating. Functional Devices offers selected RIB models in NEMA 4X configurations in addition to its standard enclosed designs.

As with electrical ratings, the enclosure should be selected for the actual conditions where the relay will be installed rather than simply using the same relay configuration throughout a project.

A practical relay selection checklist

Before specifying an enclosed relay for a building automation application, work through the electrical and installation requirements in order:

  1. Identify the control signal. Determine the voltage and available current that will energize the relay coil.
  2. Identify the load. Determine the voltage, current and type of load the contacts will switch.
  3. Select the contact configuration. Determine whether the application requires SPST, SPDT, DPDT, multiple relays or another arrangement.
  4. Check the appropriate contact rating. Verify the relay rating for the specific type of load rather than relying on a single amperage value.
  5. Evaluate wiring separation. Determine whether the application requires separate entrances or compartments for the control and contact wiring.
  6. Consider serviceability. Decide whether LED indication, local override or other features would simplify commissioning and troubleshooting.
  7. Match the enclosure to the environment. Confirm that the enclosure rating is appropriate for where the relay will be installed.

Working through those questions helps ensure the relay is selected as part of the complete control circuit, not simply as an accessory between the controller and the load.

Simplifying relay installation with Functional Devices

Functional Devices’ RIB and RIBT Pilot Series provides a broad range of enclosed relay configurations for building automation and control applications. Options include multiple coil voltages and contact configurations, LED status indication, override switch options and models designed for different installation environments.

The prepackaged RIB design can also eliminate the need to separately purchase, mount and wire components such as a relay, socket and enclosure. When an application calls for physical separation of control and contact wiring, the RIBT Series adds separate wiring entrances and a dedicated coil wiring compartment.

Whether the application calls for a general-purpose enclosed relay or additional high/low-voltage wiring separation, starting with the control signal, load and installation requirements makes it easier to choose the right configuration.

Explore Functional Devices RIB and RIBT Pilot Series relays at Kele.

Choosing between 2-way and 3-way ball valves: Making the right choice for your control strategy

Posted on by Kele Inc

Sponsored by Belimo

In building automation, a control valve does more than open and close a pipe. It helps translate a control signal into the flow needed to maintain temperature, comfort and system performance. That makes choosing the right ball valve an important part of the overall control strategy.

Valve size is only part of that decision. Before selecting a valve, consider what it needs to accomplish in the system, how flow should respond as the valve moves, the required flow capacity and how the actuator will interface with the building automation system.

Belimo’s B2 and B3 Series characterized control valves, available from Kele, provide 2-way and 3-way options for hot and chilled water applications. The B2 Series provides 2-way flow control, while the B3 Series supports 3-way mixing and diverting applications. Both use characterized flow paths designed to provide predictable control as valve position changes.

 

Determine the flow path: 2-way or 3-way?

One of the first decisions is whether the application requires a 2-way or 3-way valve.

A 2-way valve has a single inlet and outlet and regulates the amount of water flowing through the controlled path. As the actuator changes valve position, flow through that path increases or decreases. This makes 2-way valves a common choice when the control strategy calls for varying flow through the load.

A 3-way valve adds another flow path. Depending on how it is piped and applied, it can mix two streams into one or divert one stream between two paths. This makes it useful when the application requires a bypass or needs to redirect flow rather than simply reduce it.

The Belimo B2 Series is designed for 2-way control, while the B3 Series provides the additional port required for mixing or diverting applications.

The right ball valve helps translate a control signal into the flow needed to maintain temperature, comfort and system performance.

Flow characteristic matters

Selecting between 2-way and 3-way control is only the beginning. How the valve responds as it moves through its operating range also affects control performance.

The Belimo B2 Series uses an equal-percentage flow characteristic. With equal-percentage control, equal changes in valve position produce equal percentage changes in flow rather than equal absolute changes. This provides finer control at lower flow rates while allowing progressively greater changes in flow as the valve opens.

The B3 Series applies that same equal-percentage characteristic through the A-to-AB control path. The B-to-AB bypass path has a linear or modified-linear characteristic. That combination is intentional: Belimo designs the bypass characteristic to help maintain more consistent common-port flow as the valve moves through its operating range.

Valve position and water flow are not automatically the same thing. The valve’s design helps determine how a command from the controller translates into actual flow through the system.

For a building automation system, those characteristics matter because valve position and water flow are not automatically the same thing. The valve’s design helps determine how a command from the controller translates into actual flow through the system.

Don’t choose a valve by pipe size alone

Once the configuration is determined, the valve still has to be sized for the application. One of the key values is Cv, or flow coefficient. Cv represents the amount of water, in gallons per minute, that will flow through a valve with a 1 psi pressure drop across it.

It can be tempting to select a control valve simply by matching the valve connection size to the pipe. But a control valve that is too large for the required flow can make precise control more difficult. A valve that is too small can create excessive pressure drop and may not provide the required flow.

Instead, valve selection should consider the application’s design flow and available differential pressure. Belimo offers the B2 and B3 families in multiple sizes and Cv ratings, allowing the valve to be selected around the application’s flow requirements rather than pipe size alone. Proper sizing also helps the building automation system make better use of the valve’s operating range instead of trying to control most of the load within a small portion of valve travel.

For 3-way valves, port orientation is critical

Three-way valves introduce another important consideration: the ports are not interchangeable. On Belimo B3 characterized control valves, the ports are identified as A, B and AB. Belimo specifies AB as the common port and requires the A port to be piped to the coil for proper control. The B port serves as the bypass path.

Piping the B port to the coil instead can interfere with the valve’s intended flow characteristics and prevent the system from controlling as designed. Belimo also notes that flow is not possible directly from A to B. For installers and technicians, checking the valve’s port markings before installation is a simple step that can prevent a much more difficult control problem during commissioning.

Match the actuator to the control strategy

The valve body is only one half of the control assembly. The actuator also needs to match the BAS control strategy and the application’s requirements. Belimo B2 and B3 valves can be paired with actuator options supporting different types of control, including on/off, floating and proportional/modulating operation.

On/off control moves the valve between defined open and closed positions and is appropriate when the application does not require modulation. Floating control uses drive-open and drive-closed signals to position the valve between its endpoints. Proportional control positions the valve in response to a modulating control signal, allowing the BAS to adjust valve position as operating conditions change.

Another consideration is whether the application requires fail-safe operation. Spring-return or other fail-safe actuator options can move the valve to a defined position when power is lost, while non-fail-safe actuators remain appropriate for applications where automatic return on power loss is not required. Some Belimo actuator combinations also offer MFT programmable functionality, providing additional configuration options for parameters such as control signal, feedback and operating characteristics.

Put the pieces together

Ball valve selection for building automation comes down to a series of connected decisions:

  1. Determine the required flow path. Does the application need 2-way flow control or 3-way mixing, diverting or bypass operation?
  2. Determine the required flow. Use design flow and differential pressure to select the appropriate Cv rather than choosing solely by pipe size.
  3. Consider the flow characteristic. Understand how valve movement will translate into flow through the controlled and bypass paths.
  4. Select the control method. Determine whether the BAS requires on/off, floating or proportional control.
  5. Determine the fail-safe requirement. Decide what the valve should do if power is lost and select the actuator accordingly.
  6. Verify installation requirements. Confirm flow direction and, with 3-way valves, make sure each port is piped according to the manufacturer’s requirements.

When those decisions are considered together, the valve and actuator become an integrated part of the control strategy rather than simply components installed in the piping.

Ball valve control with Belimo B2 and B3 Series

Belimo B2 and B3 Series characterized control valves provide a range of options for building automation applications requiring 2-way or 3-way water control. Designed for hot and chilled water with up to 60% glycol, the series combines multiple Cv options with a broad selection of compatible actuator and control configurations.

Whether the application calls for straightforward 2-way flow control or 3-way mixing or diverting, starting with the system requirements makes it easier to select a valve and actuator combination that delivers the intended control.

Pressure sensors 101: Static, differential and wet media

Posted on by Kele Inc

Pressure sensors play a critical role in HVAC and building automation systems (BAS), helping maintain airflow, monitor system performance, and ensure proper operation of equipment.

From controlling fan speeds to verifying filter conditions and maintaining building pressurization, pressure sensors provide the feedback needed for stable and efficient control.

While the concept of pressure measurement seems straightforward, there are several types of pressure sensors used in HVAC applications—each designed for a specific purpose. Understanding the differences between static, differential, and wet media pressure sensors is essential for selecting the right device.

What pressure sensors do in HVAC systems

Pressure sensors measure the force exerted by air or fluid within a system and convert that measurement into a signal that can be used by a DDC controller.

In HVAC systems, these measurements are used to:

  • Maintain duct static pressure
  • Monitor airflow and system balance
  • Detect dirty filters
  • Control fan and pump operation
  • Maintain room pressurization in critical spaces

For example, a pressure input from a Kele KDP2M differential pressure sensor can be used to modulate a fan via a VFD, ensuring consistent airflow while minimizing energy use.

Comparing pressure sensor applications

Sensor/application

What it measures

Medium

Common HVAC applications

Example devices

Dry differential: duct static pressure

Duct pressure relative to ambient air; reference port open to atmosphere

Air

Duct static pressure, fan control

Kele KDP2M

Dry differential: two-point measurement

Difference between two pressure locations

Air

Filter monitoring, airflow measurement, room pressurization

Kele KDP2M

Wet gauge

Pressure at one process connection relative to an atmospheric reference

Water / glycol

Hydronic pressure monitoring

Kele P51 / PSS2

Wet differential

Pressure difference between two process connections

Water / glycol

Pump and hydronic differential pressure monitoring

Kele DPW-692

Pressure sensors: Dry differential, wet gauge and wet differential

In HVAC air systems, dry pressure sensors measure differential pressure, even when used to monitor duct static pressure. For example, connecting one port to a supply duct and leaving the low-pressure port open to atmosphere measures duct pressure relative to ambient air. This provides feedback to the BAS for fan speed control.

For wet applications, the distinction is between gauge and differential measurement:

  • Wet gauge sensors, such as the Kele P51 and PSS2 Series, use one process port to measure pressure at a single location relative to an atmospheric reference.
  • Wet differential sensors, such as the Kele DPW-692 Series, use two process ports to measure the pressure difference between two locations in a liquid system.

Differential pressure sensors: Measuring pressure difference

Differential pressure sensors measure the difference between two pressure points, making them one of the most versatile sensor types in HVAC systems.

Common applications include:

  • Monitoring pressure drop across filters
  • Measuring airflow in ducts
  • Controlling VAV systems
  • Maintaining room pressurization

For example, measuring pressure across a filter allows operators to determine when it is becoming clogged. Measuring pressure between spaces helps maintain proper room pressurization differences in healthcare or lab environments.

Devices like the KDPS differential pressure sensor and Kele RPS-W room pressure sensor are widely used for these applications.

Wet media pressure sensors: Measuring pressure in liquid systems

Wet media pressure sensors are used to measure pressure in liquid systems such as water or glycol. These sensors are designed to handle direct contact with fluids and are commonly used in:

  • Chilled water systems
  • Hot water systems
  • Pump control applications
  • Hydronic loop monitoring

Monitoring pressure in a chilled water loop allows a BAS to adjust pump speed using a VFD, improving efficiency and maintaining proper flow. Selecting the correct wet media sensor ensures compatibility with the fluid type and operating conditions.

How pressure sensors integrate with BAS and control systems

Pressure sensors are a key input in many BAS control loops.

In a typical sequence:

  • The sensor measures pressure
  • The signal is sent to a DDC controller
  • The controller compares the value to a setpoint
  • The system adjusts fan speed, damper position, or pump output

For example:

  • A duct pressure sensor works with a VFD to maintain airflow
  • A filter pressure sensor triggers maintenance alerts
  • A room pressure sensor maintains proper pressurization

Supporting devices such as the Kele FXP-10 airflow probe can complement pressure measurements by verifying airflow performance.

Common challenges with pressure sensing in HVAC

Pressure sensing must be implemented correctly to be effective. Improper sensor placement is a common issue. Poor location of sensing ports or tubing can result in inaccurate readings and unstable control.

Tubing installation also matters. Kinks, leaks, or condensation can affect measurement accuracy. Sensor range selection is critical. A sensor that is too large may lack sensitivity, while one that is too small may exceed its limits. Environmental factors such as dust or moisture can also impact performance over time.

Choosing the right pressure sensor for your application

Selecting the right pressure sensor depends on the application. For airside systems, differential pressure sensors like the Kele KDP2MP are commonly used for duct pressure and filter monitoring.

For space pressurization, devices like the Kele KDP2MP provide accurate low-pressure measurement. For hydronic systems, wet media sensors are required for measuring liquid pressure reliably.

In many systems, combining pressure sensing with airflow and temperature measurements provides the most complete view of performance.

Conclusion

Pressure sensors are a fundamental part of HVAC and BAS systems, providing the data needed to maintain airflow, monitor system health, and optimize performance. Understanding the differences between static, differential, and wet media pressure sensors ensures that the right device is selected for each application.

When properly specified and installed, pressure sensors enable more stable control, improved efficiency, and better overall system performance. In modern BAS applications, accurate pressure measurement—combined with the right control strategies and supporting devices—plays a key role in achieving reliable and efficient building operation.

How to specify VFDs for fans and pumps in BAS projects

Posted on by Kele Inc

Variable frequency drives (VFDs) have become a standard component in modern building automation systems (BAS). Used to control the speed of fans and pumps, VFDs allow HVAC systems to respond dynamically to changing demand, improving efficiency and reducing equipment wear.

While specifying a VFD may seem straightforward, proper selection requires more than matching horsepower. In BAS projects, the goal is to ensure the drive integrates seamlessly with the control system, supports the application, and delivers long-term reliability.

What a VFD does in HVAC systems

A variable frequency drive controls the speed and torque of an AC motor by adjusting the frequency and voltage of the power supplied to it. In HVAC systems, this allows fans and pumps to operate only as fast as needed rather than running at constant speed.

This is especially important because fan and pump energy use follows affinity laws, meaning small reductions in speed can result in significant energy savings.

In a BAS environment, VFDs are typically controlled by DDC controllers using inputs from sensors such as temperature, pressure, or airflow. For example, a pressure signal from a KDPS differential pressure sensor can be used to modulate fan speed, maintaining stable airflow while minimizing energy use.

Lower speed, lower theoretical power

Theoretical shaft power at reduced fan or pump speedsIllustrative cubic affinity-law calculation. At 50, 60, 70, 80, 90 and 100 percent of full speed, theoretical shaft power is 12.5, 21.6, 34.3, 51.2, 72.9 and 100 percent, respectively. Actual electrical savings vary by system.0%25%50%75%100%12.5%50%21.6%60%34.3%70%51.2%80%72.9%90%100%100%Fan or pump speed (% of full speed)Theoretical shaft powerTheoretical shaft power at reduced fan or pump speedsIllustrative cubic affinity-law calculation. At 50, 60, 70, 80, 90 and 100 percent of full speed, theoretical shaft power is 12.5, 21.6, 34.3, 51.2, 72.9 and 100 percent, respectively. Actual electrical savings vary by system.0%25%50%75%100%12.5%50%21.6%60%34.3%70%51.2%80%72.9%90%100%100%Fan or pump speed (% of full speed)Theoretical shaft power

Illustrative affinity-law calculation: power ratio = speed ratio cubed. Applies to ideal variable-torque fan and centrifugal pump loads without static lift or fixed pressure requirements. Actual electrical savings depend on the system, motor and drive. Source: Natural Resources Canada, Variable Frequency Drives. Values calculated from the cubic relationship.

Start with the motor and load, not the drive

One of the most common mistakes in specifying VFDs is starting with the drive instead of the motor and application. Proper specification begins with the motor nameplate data, including:

  • ✓ Voltage
  • ✓ Full load amps (FLA)
  • ✓ Horsepower
  • ✓ Base frequency

Current (FLA) is especially important, as VFDs are typically sized based on current capacity rather than just horsepower. Understanding the load type is equally important. Most HVAC applications involve variable torque loads, such as fans and centrifugal pumps. These loads behave differently than constant torque applications and allow for more efficient operation when paired with a properly selected VFD.

Match the VFD to the application type

Not all VFDs are designed for the same use. Selecting the right drive depends on how the system will operate. For fan and pump applications, key considerations include:

  • Variable torque rating
  • Overload capacity
  • Speed control range
  • Environmental conditions and enclosure type

For example, a supply fan system may require tight pressure control, while a pump system may operate across a wide range of speeds depending on demand. These differences affect how the VFD should be specified and configured.

In BAS applications, VFDs are often expected to support built-in control features and communication capabilities to integrate with the overall system.

Integration with BAS and control systems

A VFD is only one part of a larger control system and must be specified with integration in mind.

In most BAS applications, VFDs receive control signals from DDC controllers and adjust motor speed based on real-time inputs from field devices.

For example:

The VFD must be able to accept these inputs, whether through analog signals (0–10V, 4–20 mA) or digital communication protocols. Communication capability is also important. Many VFDs support protocols that allow them to integrate directly into the BAS for monitoring, control, and alarm reporting.

Key features to specify in VFDs for BAS projects

Several VFD features can significantly impact system performance and usability. Built-in control capabilities, such as PID control, allow the VFD to manage certain control loops locally. This can improve responsiveness and reduce dependency on the BAS for fast adjustments.

Soft start and stop functions help reduce mechanical stress on motors, belts, and piping systems, extending equipment life. Protection features, such as overload protection, fault detection, and thermal monitoring, improve reliability and reduce downtime.

In some applications, harmonic mitigation or filtering may also be required to maintain power quality and protect electrical systems. In retrofit applications, where pneumatic systems are still present, devices like the Kele UCP-722 E/P transducer or Kele EP-8000 series transducer can allow VFD-driven systems to work alongside existing control infrastructure.

Common mistakes when specifying VFDs

Several common issues can impact VFD performance if not addressed during specification. Improper sizing is one of the most frequent problems. Oversizing can increase cost and reduce efficiency, while undersizing can lead to nuisance trips and shortened equipment life.

Environmental factors are sometimes overlooked. High temperatures, dust, or moisture can affect drive performance if the enclosure and installation conditions are not properly considered. Integration challenges can also arise if the VFD is not compatible with the BAS or does not support the required control signals and communication protocols.

Finally, inadequate sensor input can limit system performance. Without accurate feedback from devices like pressure, airflow, or temperature sensors, the VFD cannot respond effectively to system demand.

Why VFDs are essential for energy efficiency and control

VFDs are one of the most effective tools available for improving HVAC system efficiency. By matching motor speed to actual demand, VFDs reduce energy consumption, minimize wear on equipment, and improve overall system stability. They also enable more advanced control strategies within a BAS, allowing systems to respond dynamically to changing conditions.

When combined with accurate field devices, VFDs provide a high level of control that is difficult to achieve with constant-speed systems.

Choosing the right components for VFD applications

Successful VFD implementation depends not only on the drive itself, but also on the supporting components.

Accurate sensing is critical. Devices like the KDPS differential pressure sensor, Kele FXP-10 airflow probe, and Kele KTD24 temperature sensor provide the feedback needed for stable control.

Verification devices such as the CS/SCS current switch help confirm that equipment is operating as expected and provide valuable diagnostic information.

In systems with mixed control strategies, integration devices like the Kele EP-8000 series transducer allow VFDs to work alongside existing infrastructure.

Selecting the right combination of components ensures that the system performs reliably and can adapt to future upgrades.

Conclusion

Specifying VFDs for fans and pumps in BAS projects requires a system-level approach. While it begins with understanding the motor and load, it also involves selecting the right drive features, ensuring proper integration with the BAS, and supporting the system with accurate field devices.

VFDs play a central role in modern HVAC systems, enabling energy savings, improved control, and longer equipment life. When paired with the right sensors and control strategies, they become a key part of a high-performing building automation system. By focusing on both the drive and the supporting components, building operators and designers can achieve better performance, greater efficiency, and more reliable operation over time.

Building automation systems explained: A practical introduction to BAS

Posted on by Kele Inc

A building automation system (BAS) is a network of hardware and software that monitors and controls building systems such as HVAC, ventilation, and energy usage. In modern buildings, BAS platforms rely on computer-based direct digital controls (DDC) to automate operation, improve efficiency, and provide real-time visibility into system performance.

While the concept sounds straightforward, the effectiveness of a BAS depends on how well its components work together—from field devices and controllers to control logic and system integration.

At its core, a BAS is only as effective as the field devices and control strategies behind it.

Systems controlled by a BAS

Most BAS platforms are centered around HVAC systems, since heating, cooling, and ventilation account for the largest portion of building energy use.

A typical BAS may control:

  • Air handling units (AHUs)
  • Variable air volume (VAV) systems
  • Chillers and boilers
  • Ventilation and exhaust systems
  • Indoor air quality (IAQ)

To do this effectively, the system relies on continuous input from sensors measuring temperature, humidity, pressure, airflow, and CO2 levels.

For example, devices like the Kele KTD24 duct temperature sensor, Kele HD20K humidity sensor, and Kele KDP2M differential pressure sensors provide the real-time data needed to maintain proper system operation. CO2 and air quality inputs from devices such as the Kele KCD sensor series or Senva AQ Pro Series allow systems to adjust ventilation based on actual occupancy and conditions.

How a BAS works: From sensors to control

A BAS operates as a closed-loop system, continuously measuring conditions, comparing them to desired setpoints, and adjusting operation to maintain those targets.

At the field level, sensors collect data from the environment. These inputs are sent to controllers, which process the information and determine how the system should respond. Controllers then send signals to actuators—such as valves, dampers, or variable frequency drives—to adjust system performance.

Accurate sensing is critical at this level. Devices like the Kele ST-W Series immersion temperature sensors or Kele KDP2M room pressure sensor series ensure that controllers are receiving reliable data, which directly impacts system stability and efficiency.

In many buildings, especially those with legacy infrastructure, integration devices like the Kele UCP-722 E/P transducer allow digital controllers to interface with existing pneumatic equipment, enabling gradual system modernization.

All of these components are connected through a communication network—often using protocols like BACnet—and are managed through a BAS front-end interface that provides operators with system visibility and control.

How BAS uses control logic to optimize performance

Beyond hardware, the intelligence of a BAS comes from its control logic.

Most modern systems use control loops—such as proportional (P), proportional-integral (PI), or proportional-integral-derivative (PID) control—to maintain stable conditions. These control strategies allow systems to respond dynamically to changes, rather than relying on fixed outputs.

For example, a temperature control loop may use input from a duct sensor like the Kele KTD24 to adjust a valve or damper position. A pressure control loop using a device like the KDP2M differential pressure sensor can regulate fan speeds to maintain consistent airflow.

Additional inputs, such as airflow measurement from devices like the Kele FXP-10 airflow station, help refine system performance by ensuring that airflow setpoints are being maintained.

These control strategies reduce energy waste, improve comfort, and minimize equipment wear by avoiding unnecessary cycling or overshooting setpoints.

Why building automation systems matter today

The role of BAS has expanded significantly in recent years.

Rising energy costs are pushing building owners to operate systems more efficiently. At the same time, labor shortages are making it more difficult to rely on manual adjustments and reactive maintenance.

Indoor air quality has also become a priority. Monitoring CO2 and IAQ is now essential for maintaining occupant comfort and meeting ventilation standards. Sensors like the Kele KCD CO2 sensor series and Senva AQ2 Pro air quality sensor Series provide the data needed to support demand-controlled ventilation strategies.

In addition, many organizations are tracking building performance as part of sustainability and ESG initiatives. BAS platforms provide the visibility needed to measure and improve energy usage over time.

Upgrading or expanding a BAS in existing buildings

Many existing buildings operate with partial or outdated control systems, including pneumatic controls or early-generation DDC.

Upgrading a BAS does not always require a complete system replacement. In many cases, improvements can be made incrementally by adding or upgrading field devices and controllers.

For example, replacing older sensors with modern digital devices such as the Kele KTD24 temperature sensor or Kele HD20K humidity sensor can immediately improve control accuracy.

Hybrid approaches can also extend the life of existing systems. Devices like the Kele UCP-822 transducer series allow digital controllers to manage pneumatic equipment, providing a bridge between legacy and modern systems.

Adding measurement and verification tools such as the Kele CS/SCS current switch can also improve system diagnostics and help operators confirm that equipment is functioning as expected.

Key BAS components that impact performance

While BAS platforms are often associated with software and interfaces, system performance ultimately depends on the quality of field devices.

Temperature sensors, humidity sensors, pressure sensors, airflow measurement devices, and air quality sensors all play a critical role in how effectively a system operates. Small inaccuracies at the sensor level can lead to larger inefficiencies across the system. Selecting reliable, high-quality components helps ensure that control strategies perform as intended.

Kele offers a wide range of building automation components—including sensors, transducers, relays, and airflow measurement devices—designed to support both new installations and system upgrades.

Conclusion

A building automation system (BAS) is more than just a control platform—it is the foundation for how modern buildings operate. By combining direct digital controls (DDC), accurate field devices, and well-designed control strategies, BAS platforms enable buildings to run more efficiently, maintain consistent conditions, and adapt to changing demands.

For organizations looking to improve performance, the most effective approach is often to start with the fundamentals: reliable sensing, strong control logic, and scalable system design. With the right components in place, a BAS can deliver meaningful improvements in efficiency, comfort, and long-term operational value.

Understanding control loops (P, PI, PID) in HVAC systems

Posted on by Kele Inc

Modern HVAC systems rely on more than just sensors and equipment—they depend on how those components are controlled. At the core of that control is the concept of control loops.

In direct digital controls (DDC) and building automation systems (BAS), control loops determine how systems respond to changing conditions. Whether maintaining temperature, airflow, or pressure, the type of control loop used—proportional (P), proportional-integral (PI), or proportional-integral-derivative (PID)—has a direct impact on performance, efficiency, and stability.

Understanding how these loops work helps building operators and contractors make better decisions when designing, upgrading, or troubleshooting HVAC systems.

What is a control loop in HVAC systems

A control loop is a process where a system continuously measures a condition, compares it to a desired setpoint, and makes adjustments to maintain that target.

In HVAC systems, this typically involves:

  • A sensor measuring a variable (temperature, pressure, airflow)
  • A controller comparing that value to a setpoint
  • An actuator adjusting equipment (valves, dampers, fans)

For example, a duct temperature sensor like the Kele KTD24 duct temperature sensor provides input to a controller, which then adjusts a valve or damper actuator to maintain the desired temperature.

Accurate sensing is critical for effective control. Devices like Kele immersion temperature sensors or Kele KDP2M differential pressure sensor ensure that controllers are working with reliable data, which directly impacts loop performance.

Proportional (P) control: The foundation of HVAC control loops

Proportional control is the simplest form of control loop. It adjusts the output based on how far the measured value is from the setpoint. The larger the difference (or “error”), the stronger the response.

In HVAC systems, this might mean opening a valve more as the temperature drops further below the setpoint. As the system approaches the desired temperature, the adjustment becomes smaller. While proportional control is simple and responsive, it typically cannot eliminate error completely. This often results in a steady-state offset, where the system stabilizes slightly above or below the desired setpoint.

Proportional-integral (PI) control: Eliminating steady-state error

PI control builds on proportional control by adding an integral component. This component accounts for accumulated error over time and adjusts the output to eliminate long-term offset.

In HVAC applications, PI control is commonly used for:

  • Temperature control in air handling units
  • Zone-level control in VAV systems
  • Hydronic loop control

By correcting for steady-state error, PI control provides more accurate and stable performance than Proportional control alone. Reliable feedback is essential for PI control to function properly. Sensors such as the Kele HD20K duct humidity sensor help ensure that the system is responding to accurate environmental conditions.

Proportional-integral-derivative (PID) control: Precision and responsiveness

PID control adds a third component: derivative control. This element predicts how the system will respond based on the rate of change, allowing it to react more quickly and prevent overshooting the setpoint.

In HVAC systems, PID control is especially useful in applications where conditions change rapidly or require tight control, such as:

  • Supply air temperature control
  • Static pressure control
  • Critical environments like labs or healthcare spaces

For example, using a pressure sensor like the Kele KDP2M differential pressure sensor series in a PID loop allows a system to adjust fan speeds more precisely, maintaining stable airflow without excessive fluctuations.

PID control provides the highest level of performance, but it also requires proper tuning. Poorly tuned PID loops can lead to instability, oscillation, or inefficient operation.

The key differences between P, PI and PID control are summarized in the table below.

 

Comparison P PI PID
Control action

Present error

Present + accumulated error

Present + accumulated + rate of change
Main consideration

May leave offset

Requires tuning

Requires tuning; derivative sensitive to noise

How control loops impact energy efficiency and system performance

The type of control loop used has a direct impact on how efficiently an HVAC system operates.

Poorly controlled systems tend to:

  • Overshoot setpoints
  • Cycle equipment unnecessarily
  • Waste energy through constant adjustment

Well-tuned PI and PID loops reduce these issues by maintaining stable conditions and minimizing unnecessary system movement.

For example, integrating airflow measurement devices like the Kele FXP-10 airflow station allows controllers to make more precise adjustments, improving both comfort and efficiency.

Similarly, current sensing devices such as the Kele CS, SCS Series can verify equipment operation, helping ensure that control sequences are functioning as intended.

Common control loop challenges in HVAC systems

Even with advanced DDC systems, control loop performance depends heavily on proper setup and component selection. One common issue is poor sensor placement or inaccurate readings. If the input data is wrong, even the best control strategy will fail. Using high-quality sensors and placing them correctly is critical.

Another challenge is improper loop tuning. Many systems operate with default settings that are not optimized for the specific application, leading to instability or sluggish performance. System lag can also impact control performance. Delays between measurement and response—common in large systems—must be accounted for, especially in PID loops. Addressing these challenges often starts with upgrading sensing and feedback devices, followed by proper tuning of the control logic.

Choosing the right components for effective control loops

Effective control starts with selecting the right field devices. Temperature sensors like the Kele KTD24 duct sensor provide accurate input for thermal control loops. Pressure sensors such as the Kele KDP2M Series differential pressure sensors support airflow and static pressure control.

Humidity and air quality sensors, including the Kele HD20K humidity sensor and Senva AQ Pro Series add another layer of insight for advanced control strategies.

In systems that still rely on pneumatic components, devices like the Kele UCP-722 transducer allow DDC controllers to maintain precise control over existing equipment. By combining accurate sensing with properly tuned control loops, buildings can achieve more stable operation and improved efficiency.

Conclusion

Control loops are at the heart of every HVAC system. Whether using P, PI, or PID control, the goal is the same: maintain stable conditions while minimizing energy use and system wear.

Direct digital controls (DDC) make it possible to implement advanced control strategies, but the effectiveness of those strategies depends on both proper tuning and reliable field devices.

By understanding how control loops work and selecting the right components, building operators can improve performance, reduce costs, and create more comfortable indoor environments.

Cold-weather prep: Look beyond part number when replacing a control valve

Posted on by Kele Inc

Start with the application, not the part number

A valve tag is valuable, but it is only the beginning.

Before selecting a replacement, identify what the valve is controlling and how the system is intended to operate. Is it serving a heating coil or cooling coil? Is it a two-way or three-way application? Should the valve fail open or closed? Is the actuator two-position, modulating, floating, or pneumatic? What should happen if power or the control signal is lost?

Those questions are particularly important in older facilities, where what is installed may no longer match the original plans or sequence of operation.

The Siemens 599 Series is a good example. A technician may recognize “599” on the valve and assume that is enough information to identify a replacement. In reality, the name covers several distinct control valve families.

599 family What it is Key distinction
599 Series zone valves Small two- and three-way globe valves 1/10-in. (2.5 mm) stroke
599 Series ball valves Quarter-turn control valves Rotary actuation
Flowrite™ VF 599 Series Globe valves for larger applications 3/4-in. (20 mm) stroke; electronic or pneumatic actuation

Same 599 name. Very different valves and actuator requirements.

That’s why identifying the complete assembly, rather than simply matching the most visible number, matters.

Make sure the actuator matches the job

Don’t overlook the problems that look like valve failures

A valve that isn’t controlling properly doesn’t automatically need to be replaced.

Before condemning the hardware, check the basics around it: control signal, wiring, power supply, actuator travel, linkage or mounting, and the BAS command. Verify that the actuator can actually drive the valve through its required range.

Manufacturer instructions can reveal less obvious issues, too. Siemens specifies correct polarity on its 24 Vac electronic actuators and cautions against powering certain actuators before they are attached to a valve. Some models perform a calibration stroke at startup, making proper assembly and commissioning part of correct operation.

These are small details with potentially expensive consequences. A new actuator installed on an existing wiring problem isn’t likely to solve the service call.

Don’t assume the old valve was sized correctly

Like-for-like replacement also carries another risk: repeating an old sizing problem. Control valves should be selected based on the application’s required flow and pressure conditions, not simply the pipe diameter. An oversized valve can make stable control difficult, even when the valve and actuator are functioning exactly as designed.

If a unit has always struggled to maintain temperature, hunts around setpoint, or seems to operate primarily near one end of the valve’s travel, replacement is an opportunity to verify the original selection rather than automatically reproduce it.

For the Siemens 599 line, published capacity graphs, Cv data, and close-off pressure information can be used to check the application. Siemens also publishes control-valve selection and sizing guidance for working through the calculations. A few extra minutes spent verifying the application can be more valuable than finding the replacement part number quickly.

When the wrong valve becomes a frozen coil

In a unit ventilator, fan coil, or similar application, valve selection can also be tied directly to freeze protection.

Consider a heating coil where a freezestat is intended to protect the equipment during low-temperature conditions. If a previous repair changed valve action, altered the wiring, or bypassed part of the original control sequence, the system may appear to operate normally until the conditions that require freeze protection actually occur.

Then the consequences can be much larger than a failed actuator: a frozen or ruptured coil, water damage, an occupied space without heat, and an emergency repair.

Before putting seasonal equipment back into service, confirm that the valve and actuator respond as the sequence requires and that freeze protection is actually capable of overriding normal control when needed.

That is especially worth checking on equipment with a history of unexplained winter failures or components that have clearly been replaced over the years.

Treat the fall walkthrough as an identification exercise

The best time to sort through an unfamiliar control valve isn’t during a November no-heat call.

During preseason maintenance, photograph the valve tag and actuator label together. Record the line size and whether the valve is two-way or three-way. Note the control signal and required action. If drawings or sequences are available, compare what is installed with what the system was designed to do.

For Siemens 599 Series valves, the documentation can then narrow the identification further. The different valve and actuator families have their own technical instructions covering dimensions, wiring, capacity, close-off pressure, installation, and compatible actuators.

And if the tag is unreadable or the combination doesn’t make sense, stop before ordering. A photo of the existing valve, actuator, piping, and labels can often reveal far more than a partial part number.

Know what you’re replacing before you replace it

Control valve replacement should be a straightforward maintenance task. The problems usually begin when “replace the valve” becomes shorthand for “order whatever looks like the one that’s there.”

Start with the application. Confirm the valve family, action, actuator, control signal, sizing, and sequence. Then use the manufacturer’s documentation to identify the component that satisfies those requirements.

For Siemens 599 Series applications, Kele provides the associated technical literature on its product pages, and Kele technical support can help with valve identification, sizing, actuator selection, and crossover questions when the existing installation doesn’t provide a clear answer.

Need help identifying a Siemens 599 Series valve or actuator? Photograph the valve tag, actuator label, and installation before you remove anything. Kele’s technical support team can help determine what you have and what the application requires.

Tridium security update for specific Niagara systems

Posted on by Kele Inc

Summary

Tridium has identified a software security issue affecting the Program Module in certain supported Niagara Framework and Niagara Enterprise Security versions. If your system is running Niagara 4.14u5 or 4.15u4, you should review the available update options and plan to apply the appropriate correction. Kele is sharing this notice so you can confirm your installed version and take action where needed.

 

Manufacturer Product or family Affected version
Tridium Niagara Framework 4.14u5
Tridium Niagara Enterprise Security 4.14u5
Tridium Niagara Framework 4.15u4
Tridium Niagara Enterprise Security 4.15u4

 

Why this matters to you

The issue affects software access controls within the Niagara Program Module. Updating affected systems helps reduce the risk of unauthorized changes or increased access within your Niagara environment.

 

Kele engineering recommendation

Kele Engineering’s current recommendation:

  1. Confirm the Niagara product and software version installed at your site.
  2. If you are running an affected version, review Tridium’s official technical bulletin.
  3. Apply the appropriate Tridium patch or upgrade to Niagara 4.14u6 or 4.15u5, based on your system requirements and support path.
  4. Review authorized user accounts, physical system access, remote-access protections, module signing, and Security Dashboard warnings.
  5. Contact Kele Technical Support before updating if you need help determining the correct update path.

 

What you should do

Please confirm your installed Niagara version and schedule the appropriate update if your system is running 4.14u5 or 4.15u4.

Tridium lists the following targeted patch files:

  • program-rt-4.14.5.22.1.jar
  • program-rt-4.15.4.24.1.jar

These jar files are available as a download from the Niagara Central Software Download Area as Program module patches for 4.14.5 and 4.15.4 to address CVE-2026-11804 programModulePaches.zip. Tridium also states that the correction is included in these newer releases:

  • Niagara Framework and Niagara Enterprise Security 4.14u6
  • Niagara Framework and Niagara Enterprise Security 4.15u5

 

Manufacturer information and links

For additional technical details beyond this email, review the Official Tridium Technical Bulletin.

Software updates are available through Niagara Central Software Downloads. (log-in required)

Tridium also recommends reviewing the Niagara 4 Hardening Guide for system-security best practices.

 

Contact Kele

For troubleshooting, product behavior, firmware, installation, or field issues, contact: BAsupport@Kele.com, or 833-800-3346. For licensing, pricing, quotations, availability, or orders, contact: BAorders@Kele.com | 833-800-3345

Please have your Niagara product name, installed software version, and any available system details ready when you contact us.

The hidden scheduling problem in zone valve installation

Posted on by Kele Inc

Sponsored content by Schneider Electric

 

On a hydronic HVAC project, valve selection can affect more than flow. The way a valve is designed can also influence construction sequencing, trade coordination and even how components are protected before startup.

Zone valves are relatively small components in a building automation system but installing them can involve two very different stages of construction. Early in the project, plumbers and mechanical contractors are focused on piping rough-in. Valve bodies need to go in, connections need to be made and piping needs to be tested.

Controls work typically comes later, after wiring is pulled and technicians are ready to connect and commission the system. So why should the actuator have to go in at the same time as the valve body?

One valve, two very different jobs

Consider a sweat-connected zone valve. Installing the valve body can involve soldering, torch work, pipe preparation and all the dust and debris that come with an active construction site. None of that is particularly friendly to an electrical actuator.

Heat is an especially important consideration. Schneider Electric’s installation instructions for its VT/VS PopTop™ valves specifically caution against soldering with the actuator in place because heat can damage the unit.

“A removable actuator provides a simple alternative: don’t install it yet.”

With Schneider Electric’s VT Series PopTop™ design, the valve body can be installed during piping rough-in without the actuator attached. The mechanical contractor can complete the piping and check the system for leaks. Later, when controls wiring is ready, the actuator mounts directly onto the valve body without field-installed linkage or calibration.

That changes the workflow from one installation event into two independent tasks. The important part isn’t simply that the actuator comes off. It’s that the mechanical and controls portions of the installation no longer have to happen at the same time.

Key Takeaways

A removable actuator provides a simple alternative: don’t install it yet.
Separating the valve body from the actuator removes that scheduling dependency.
Delaying actuator installation reduces exposure to heat, dust, paint and job-site handling.
Mechanical and controls completion become two clear, separate checkpoints.
The VT Series PopTop™ actuator can later be removed and replaced without disturbing the valve body or piping.

Less trade coordination can mean fewer project headaches

On a large project, mechanical crews may be working well ahead of controls contractors. Wiring may be waiting on walls, ceilings, panels or other construction milestones. If the plumber needs the controls component to complete the valve installation, another dependency has been added to the schedule.

The plumber can finish the wet side when the piping is ready. The controls contractor can finish the electrical side when the controls system is ready. That doesn’t eliminate the need for coordination between trades, but it can eliminate one reason their schedules have to overlap. And the larger the project, the more meaningful that can become. A minor coordination issue at one terminal unit is exactly that: minor. Repeat it across dozens or hundreds of valves, however, and small inefficiencies can start adding up.

“Separating the valve body from the actuator removes that dependency.”
Schedule dependency, illustrated
A fixed actuator ties mechanical and controls trades to the same window. A removable actuator lets each trade work on its own timeline.
Rough-inWiringStartupCommission
Fixed actuator
Mechanical + controls must overlap
Removable actuator
Valve body installed
Actuator added, independently
no shared dependency

Keep controls components out of the rough-in environment

There is another advantage to waiting: the actuator doesn’t have to spend the rest of construction sitting on the valve. Once an actuator is installed, it may remain in place for weeks or months before the building is commissioned. During that time, other work continues around it. Delaying actuator installation can help reduce unnecessary exposure to:

  • soldering heat
  • construction dust and debris
  • paint and overspray
  • accidental impact
  • handling by other trades
  • moisture and general job-site activity

For sweat-connected VT Series valves, Schneider goes further than simply recommending caution: its installation instructions direct installers to remove the actuator before soldering. The valve body can also be leak tested before the actuator is attached. That makes staged installation a practical part of the intended installation process, not just a workaround.

A cleaner handoff from piping to controls

Separating the installation into stages can also make startup more orderly. The mechanical side can be installed and checked before controls work begins. Once the actuator is installed and wired, the controls technician can focus on actuator operation and the control sequence. Think of it as two checkpoints:

Mechanical completion

  • Valve body installed correctly
  • Piping connections complete
  • System checked for leaks
  • Valve ready for controls

Controls completion

  • Actuator installed
  • Wiring complete
  • Valve responds to the control command
  • Proper operation verified

This separation can also be useful when troubleshooting. If the piping and valve body have already been checked, technicians have a clearer starting point when diagnosing a controls issue.

The same idea pays off after construction

Construction sequencing may be the immediate benefit, but modular valve design can matter years later too. Actuators are electromechanical components. If one eventually needs replacement, there is little reason to disturb a properly functioning valve body and hydronic connection.

The VT Series PopTop™ actuator can be removed and replaced without removing the valve body from the piping. Schneider’s current documentation also notes that actuator replacement requires no tools.
“The VT Series PopTop™ actuator can be removed and replaced without removing the valve body from the piping.”

That allows a technician to address an actuator issue without unnecessarily turning it into a piping job. It is essentially the same principle that helped during construction: Keep the wet side and controls side independent when the work only involves one of them.

Look beyond the valve schedule

Valve selection still starts with the fundamentals: application, valve configuration, flow requirements, connection type, actuator voltage and control sequence. But those aren’t the only questions worth asking. When selecting a zone valve, consider how it will move through the entire project:

  • Can the mechanical contractor install and test the valve body independently?
  • Does the actuator need to be exposed during rough-in?
  • Can controls be added later without disturbing completed piping?

Where the Schneider Electric VT Series fits

Schneider Electric VT Series PopTop™ zone valve, shown with actuator detached from valve body.
Schneider Electric VT Series PopTop™ zone valve, shown with actuator detached from valve body.

Schneider Electric's VT Series is a good example of designing around that larger installation lifecycle.

The PopTop™ design allows the valve body to go in when the mechanical system is ready and the actuator to go on when the controls system is ready. The actuator mounts directly to the valve body, and it can later be removed again for service without removing the valve itself.

It's a relatively simple design decision, but it solves a familiar job-site problem.

The plumber doesn't need to wait for controls. The controls contractor doesn't need to be there for piping rough-in. And the actuator doesn't need to spend construction sitting next to a torch before it ever receives power.

Sometimes making installation easier isn't about doing the work faster. It's about making sure two trades don't have to do their work at the same time.