Ensuring Reliable Fuel Monitoring with the QPx32 Gas Pressure Switch

Ensuring Reliable Fuel Monitoring with the QPx32 Gas Pressure Switch

Overview 

The Siemens Combustion Controls (SCC) QPx32 series pressure switch is a compact, reliable device that monitors gas or air pressure in combustion systems and HVAC applications. It detects when pressure rises above or below a set threshold and then actuates an internal Form C (SPDT) contact to alert control systems or shut down equipment if needed. In practical terms, the QPx32 safeguards burners, boilers, and other gas-fired or air-handling equipment by signaling unsafe pressure conditions. It is compatible with many fuels and gases – including natural gas, propane, butane, hydrogen, biogas, and air – making it versatile for many commercial and industrial settings. Overall, the QPx32 pressure switch helps maintain critical pressure levels, protecting both equipment and safety. 

Features and Benefits 

The QPx32 pressure switch family offers numerous features focused on safety, versatility, and ease of use. All models are cULus (UL 353) listed and FM-approved for common combustible gases, which means they meet rigorous safety standards for the U.S. and Canada. They are built to handle various fuel types – not only standard gases like natural gas and propane but also hydrogen or blended hydrogen fuels – reflecting a forward-looking design for emerging energy sources. Automatic-reset and manual-reset versions are available, allowing users to choose a configuration that suits their application’s safety requirements. A manual-reset model must be physically reset after a trip (ideal for critical safety interlocks that demand human inspection). In contrast, an automatic reset model will restore once the pressure returns to an acceptable range. Each switch is housed in a robust NEMA 4-rated enclosure, which is dust-tight and watertight for dependable outdoor or wash-down area operation. Most QPx32 units are designed to operate in ambient temperatures from -40°F to 140°F (-40°C to 60°C) without issue, ensuring functionality in harsh winter conditions or hot mechanical rooms alike.  

In addition to safety approvals, the QPx32 series incorporates practical features that simplify installation and maintenance. For example, there is a built-in test connection on the side of each switch, which allows technicians to easily attach a manometer or pressure gauge to verify the pressure or test the setpoint calibration. This eliminates the need for extra T-fittings or special test adapters during routine system checks. The electrical hookup is also straightforward: a standard 1/2-inch conduit fitting can be attached directly to the switch body without any adapters, making wiring installation quick and secure. Internally, the switch’s contact mechanism uses gold-plated contacts over a silver alloy base to ensure reliable electrical performance. The gold plating prevents oxidation and guarantees that even very low current signals (for example, from modern electronic controllers) will register consistently. From a pressure handling perspective, the QPx32 can withstand up to 15 psig (1 bar) of inlet pressure on its sensing port. Notably, it is designed for ventless operation up to 7 psig, meaning that under normal operating pressures, it will not bleed gas to the atmosphere. This ventless design enhances safety (no continuous gas venting) and simplifies compliance since no vent line or vent limiter is required for pressures at or below 7 psi. All these features contribute to a pressure switch that is convenient to use, durable, and aligned with safety best practices. 

Applications 

SCC’s QPx32 series is used across various commercial and industrial applications for gas and air pressure monitoring, particularly in burner management and HVAC systems. A QPx32 switch often monitors the fuel gas supply pressure in gas-fired burners, boilers, and furnaces. It will trip if the pressure is too low or too high, preventing unsafe combustion conditions like flameouts or over-pressurization. One everyday use is in valve proving systems: before a burner ignites, the control system may close off the gas line and use a QPx32 automatic reset switch to verify that line pressure holds steady. If the pressure falls when it shouldn’t, it indicates a leaking safety shutoff valve and the QPx32 will detect this drop and help lock out the system. In this way, the switch acts as a crucial safety check to ensure gas valves seal properly before ignition. The QPx32 is also an air pressure-producing switch on blowers and ventilation fans. For example, on a combustion air blower or an HVAC supply fan, the switch can confirm that airflow is present by sensing the pressure created in the airflow. Should a fan fail to start or a duct get blocked, the pressure will not reach the switch’s setpoint, and the QPx32 will prevent the burner from firing or shutting down the process, averting potential hazards. 

Another important application of the QPx32 series is in differential pressure monitoring. The device has a vent port that can be used as a reference port, allowing it to measure the difference between two pressure points. By connecting the vent port to a secondary location, the QPx32 can serve as a differential air pressure switch. This is useful in scenarios like monitoring filter health in an air handling unit (where the switch measures pressure drop across the filter) or proving flow in exhaust and recirculation fan systems. For instance, in an exhaust fan system, the QPx32 might sense the slight vacuum in the flue or stack when the fan is running. If the exhaust fan stops and that vacuum disappears, the switch will drop out and signal a fault condition – preventing continued operation without proper ventilation. Similarly, in a recirculation or building pressurization system, the QPx32 can verify that a fan maintains the required airflow or pressure differential between spaces. Thanks to its reliability and versatility, the QPx32 series is used as a critical safety interlock in all these applications, helping to ensure that processes only run under the correct pressure conditions. 

Competitive Analysis 

Through several key advantages, the QPx32 series distinguishes itself from competing gas pressure switches offered by companies like Dungs and Honeywell (Kromschröder). One standout feature is its ventless operation capability: unlike many traditional pressure switches requiring a vent or vent limiter to release gas from the sensing chamber safely, the QPx32 does not need to vent gas to the atmosphere at settings up to 7 psi. Competing models often must be connected to a vent line or incorporate a vent-limiting device to comply with safety codes, which adds complexity to the installation. By engineering the QPx32 to be essentially gas-tight in everyday use, SCC has simplified installation and eliminated a potential source of gas leakage. This ventless design means no continuous bleed of gas – a significant safety and cost consideration, especially for indoor installations where venting gas is undesirable. It also reduces maintenance and inspection requirements associated with vent line routing or clogging. 

Another competitive advantage of the QPx32 is that it includes the integrated test connection on every unit. This built-in test port sets the QPx32 apart from some Dungs and Kromschröder pressure switches, which may require additional adapters or external ports to perform setpoint checks. With the QPx32, a technician can quickly attach a gauge or manometer to the switch to verify pressures or troubleshoot, saving time during commissioning and routine service. Regarding pricing, the Siemens (SCC) QPx32 series is generally cost-competitive with these rival products, often providing a more affordable option for equivalent performance. Users benefit from Siemens’ quality and engineering – such as the gold-plated contacts for reliability and the NEMA 4 weatherproof housing – at a price point that can be very attractive compared to imported European switches. Overall, when stacked against similar offerings from Dungs or Honeywell/Kromschröder, the QPx32 series delivers ventless safety, convenient testing features, and firm value without sacrificing the technical capabilities required for modern combustion control systems. 

Technical Specifications 

The QPx32 series encompasses a range of models covering various pressure setpoint spans and configurations. Available setpoint pressure ranges extend from as low as about 0.2″ WC (inches of water column) up to 200″ WC, which is approximately 7.3 psi. This wide range means a single product family can handle very slight pressures (for example, detecting a tiny air flow or draft) and relatively higher pressures encountered in fuel gas lines. All QPx32 variants share a maximum operating pressure of 15 psig (1 bar), so they can safely withstand surges or over-pressure up to that limit without damage. The switches are compact and lightweight (weighing roughly 8 ounces, with a die-cast aluminum lower body and a clear polycarbonate cover that allows a view of the internal setpoint dial. 

Each model is equipped with a 1/4″ NPT pressure inlet port on the bottom (the “+” port) and a secondary 1/8″ NPT port that can serve as a vent or negative (-) pressure connection for differential measurements. The electrical conduit connection is a threaded 1/2″ NPSM hub on the side, accommodating standard 1/2″ flexible conduit fittings. Installation is flexible: the QPx32 can be mounted in any orientation except upside-down (inversion is not allowed). For best accuracy, the manufacturer recommends mounting with the diaphragm vertical since a horizontal orientation can cause a minor shift in the switching point due to gravity. In practice, the unit can be installed on piping or panels at convenient angles without issue, but one should avoid mounting it with the cover facing downwards. No special brackets are needed as the device typically threads directly onto a 1/4″ pipe nipple at the sensing point; wrench flats are provided on the base to assist in tightening. 

The QPx32 uses a snap-action SPDT switch internally to change state when the pressure threshold is crossed. Its electrical ratings support a wide range of control systems: the contact can handle up to 8 A of resistive load on 24–125 VAC circuits, and it is also rated for DC control voltages (up to 48 VDC, switching up to 100 mA). The gold-plated contact design makes the switch reliable even at very low currents (down to 20 mA), essential for direct interface with electronic burner control units or PLC input cards. The QPx32 series meets UL 353 and FM 3510 standards for safety shutoff devices and is CSA certified, ensuring it complies with relevant electrical and fuel gas codes. In terms of longevity, the mechanical life of the pressure switch is excellent: the automatic reset models are endurance-tested to over 100,000 cycles, and the manual reset versions exceed 6,000 cycles of operation at the full load rating. This durability is well above the demands of typical service, meaning the device will perform reliably through many years of regular use. Overall, the technical specifications of the Siemens SCC QPx32 pressure switch underscore its capability to operate over a broad range of conditions while delivering safe, accurate, and repeatable performance in critical pressure monitoring applications.

Combustion Technology, LLC
http://combustion-tech.net
800-327-1831

Driving Performance: Combustion Technology, LLC’s Innovations in Industrial Heat

Driving Performance: Combustion Technology, LLC’s Innovations in Industrial Heat

Combustion Technology, LLC operates out of Vancouver, Washington, and provides advanced combustion systems for various industrial heating applications. The company designs and supplies multiple products that address complex thermal processing challenges in industries such as metal heat treating, forging, ceramics, and food processing.

Engineers at Combustion Technology, LLC focus on developing high-efficiency industrial burners that meet rigorous performance standards. They offer a variety of burner types, including direct-fired models for ovens and furnaces, regenerative systems for high-temperature processes, and low-NOx solutions that help facilities comply with strict emissions regulations. Clients rely on these burners to achieve uniform heating, reliable ignition, and stable flame control in environments that demand precise temperature management.

The company also provides a full suite of combustion controls and safety components. These controls allow operators to fine-tune heat output and monitor real-time burner performance. Features such as flame monitoring and gas flow sensors improve safety measures and reduce the chance of accidental shutdowns or downtime. In addition, Combustion Technology, LLC supplies customizable control panels that integrate seamlessly with existing plant automation systems. Each panel typically includes instrumentation, flame safeguard devices, and communication interfaces that help staff supervise critical parameters without losing focus on production goals.

Industrial facilities also benefit from the company’s selection of valves and regulators. Combustion Technology, LLC sources robust components that withstand demanding thermal cycles and high-pressure conditions. By offering compatible valving solutions, the company streamlines installation and service procedures, which helps reduce operational inefficiencies for plant engineers and maintenance teams.

Beyond hardware, Combustion Technology, LLC supports customers with engineering consultation and field service. Its experts collaborate with plant managers to configure reliable burner systems, select correct sizing, and optimize process heating strategies. When equipment requires upgrades or retrofits, technicians perform on-site evaluations and recommend cost-effective adjustments that extend the system's lifespan. This approach keeps facilities running at peak performance, mainly when production lines handle diverse materials or face frequent process changes.

Industrial firms in heat treating, forging, ceramics, food processing, and chemical manufacturing often require more than off-the-shelf heating solutions. Combustion Technology, LLC works closely with these customers to deliver custom burners and integrated control packages that align with project goals. This adaptability allows the company to maintain strong relationships across multiple markets and ensure that each solution matches the unique thermal profile of every application. Whether an operation involves continuous or batch processing, clients can rely on Combustion Technology, LLC, to offer equipment that improves throughput, lowers fuel consumption, and meets regulatory standards.

In addition, the company’s commitment to research and development drives ongoing improvements in thermal efficiency. Engineers evaluate emerging technologies and refine existing product lines so customers can adopt more sustainable practices. Initiatives such as reduced excess air strategies, waste heat recovery, and advanced temperature controls help facilities minimize fuel costs and environmental impacts.

Combustion Technology, LLC aims to remain a trusted resource for industrial heating solutions by combining technical expertise, comprehensive product offerings, and personalized customer support. Manufacturers and process plants turn to this Vancouver-based company to solve tough combustion challenges, maintain compliance with emissions guidelines, and improve production efficiency. Combustion Technology, LLC delivers solutions that enhance performance for a broad spectrum of industrial heating applications through continuous innovation and hands-on service.

Combustion Technology, LLC
http://combustion-tech.net
800-327-1831

Inside the Next Generation of Industrial Combustion: Efficiency, Emissions, and Digital Intelligence

Next Generation of Industrial Combustion

Global industries recognize the urgency of improving combustion and process heating methods for economic advantages and environmental responsibility. Rising energy costs, strict regulations, and growing commitments to carbon reduction push plant operators to search for technologies that deliver efficiency gains and lower emissions. Manufacturers have responded with a range of innovations, and many of these developments focus on more significant control over the combustion process, more effective use of waste heat, and the adoption of alternative fuels. These trends also emerge alongside digitalization initiatives that use advanced analytics and automation to unlock new performance levels.

Engineers continue refining burner designs to reduce emissions without compromising output or product quality. Low-NOx and ultra-low-NOx burners minimize peak flame temperatures by staging combustion or recirculating flue gas, which helps plants meet strict regulatory limits on nitrogen oxide emissions. Oxy-fuel burners, which rely on pure oxygen rather than ambient air, enable higher flame temperatures and lower total flue gas volume, simplifying carbon dioxide capture when operators choose that route. Some facilities have experimented with flameless combustion to create a more uniform temperature profile and curb the formation of NOx. Others prepare for a gradual shift toward hydrogen by installing hydrogen-ready burners that address the higher flame speed and different material demands of that fuel.

Digitalization efforts now go beyond simple data gathering and move toward integrated solutions that boost efficiency and reduce downtime. In-situ sensors and laser-based measurement systems capture real-time insights into oxygen concentration, temperature, and combustion by-products. These readings feed into machine learning models that predict potential problems, detect faulty operations, or recommend process adjustments. Many facilities have begun using digital twins, or virtual replicas of their furnaces or boilers, to simulate the impact of process changes before making physical modifications. Engineers can then compare real-time data against these simulations to spot deviations and inefficiencies and act before problems cause costly interruptions.

Waste-heat utilization strategies continue to prove essential for cutting overall energy consumption. Regenerative burners and modern recuperators use the outgoing hot exhaust to preheat incoming combustion air, which significantly trims fuel requirements. More advanced setups include waste-heat boilers that harness hot exhaust streams to generate steam or hot water without additional fuel. Facilities that operate across various temperature levels sometimes install industrial heat pumps to upgrade low-grade waste heat into more valuable heat at higher temperatures. These steps often pay off quickly, and many plant managers consider them a straightforward way to reduce emissions and energy costs.

While combustion remains a mainstay in many industrial operations, electrification has grown more appealing, especially for lower-temperature processes. Electric ovens, infrared heaters, and hybrid gas-electric furnaces grant plant operators more flexibility in balancing energy costs and decarbonization goals. Meanwhile, process designers continue to develop advanced materials and coatings for furnace linings and heat exchanger surfaces that tolerate higher temperatures, resist corrosion, and transfer heat more effectively. These improvements enhance furnace longevity and help keep performance consistent. Every innovation, whether from better burner technology, data-driven controls, or clever waste-heat recovery, reflects an industry-wide push toward cleaner, more cost-effective operations. The shared goal remains clear: deliver high performance while reducing environmental impact and staying competitive in a world that values sustainability more than ever.

Combustion Technology, LLC
http://combustion-tech.net
800-327-1831

Merry Christmas and Happy New Year from Combustion Technology

Merry Christmas and Happy New Year from Combustion Technology

At Combustion Technology, we express our gratitude for your loyalty and trust in us throughout the year. Your continued business and partnership mean the world to us, and we are truly thankful for the opportunity to serve you. As we celebrate this holiday season, we wish you a Merry Christmas and a joyful time with your loved ones. May the New Year bring you and your family health, happiness, and success. Thank you for being an invaluable part of our journey—we look forward to another year of working together and achieving great things in 2025!

Keep Operations Running with Combustion Technology’s Eclipse Veri-Flame Replacements

Keep Operations Running with Combustion Technology’s Eclipse Veri-Flame Replacements

When it comes to replacing the discontinued Eclipse Veri-Flame burner control system, Combustion Technology, LLC stands out as a reliable and trusted source, offering seamless, high-performance solutions. With a ready inventory of state-of-the-art drop-in replacements for the Veri-Flame system, Combustion Technology ensures your operations remain uninterrupted and compliant with modern standards.

Don’t let the obsolescence of the Eclipse Veri-Flame disrupt your processes. Contact Combustion Technology, LLC today for your replacement solution and regain peace of mind, knowing your system has the components needed to keep your operations running smoothly.

Combustion Technology, LLC
http://combustion-tech.net
800-327-1831

Introducing the Phoenix TH Burner System: Cleaner Combustion and Extended Tube Life

Introducing the Phoenix TH Burner System: Cleaner Combustion and Extended Tube Life


Introducing the Phoenix TH Tube Fired Burner and Optional RH Exhaust Recuperator


In the quest for enhanced efficiency and performance in industrial heating applications, the Phoenix TH Tube Fired Burner emerges as a leading solution. Designed specifically for firing into radiant and immersion tubes, the TH burner offers an optional integration with the multi-tube RH Exhaust Recuperator, pushing the boundaries of energy efficiency even further.

Innovative Design for Optimal Heat Transfer


At the heart of the TH burner's effectiveness is its industry-proven nozzle design. This design generates a spiraling flame that actively scrubs the inside of the fire tubes. This action not only increases heat transfer but also ensures enhanced temperature uniformity within the tubes. The result is prolonged tube life and consistent heating performance, critical factors in demanding industrial processes.

Versatility Across Applications


The TH burner boasts adjustable flame lengths and multi-fuel capabilities, making it ideal for a variety of tube firing applications. It adeptly handles ambient or pre-heated combustion air and is compatible with straight, U, and W-type tube designs. Whether operating on natural gas or propane, the burner requires no internal changes when switching fuels, offering unparalleled operational flexibility.

Maximizing Efficiency with the RH Exhaust Recuperator


For processes that demand peak system efficiency, the optional RH Exhaust Recuperator is a game-changer. By recovering energy losses at the exhaust, it preheats the combustion air entering the TH burner to temperatures up to 1,000°F. This recuperation can lead to fuel savings of up to 30% or more, significantly reducing operational costs and environmental impact.

Technical Specifications


- Input Capacity Range: 100,000 – 750,000 BTU/hr
- Low Fire Input: 5,000 BTU/hr
- Flame Detection: Flame rod or UV scanner
- Ignition: Direct spark
- Max. Inlet Air Temperature: 1,000°F

Features and Benefits


- Uniform Tube Temperature: Ensures consistent product heating, enhancing quality and reliability.
- Clean Combustion: Operates without soot formation and maintains low NOx and CO emissions, promoting environmental compliance.
- High Efficiency: Functions efficiently with low excess air and accommodates pre-heated combustion air up to 1,000°F.
- Reliable Ignition: Offers consistent performance across a wide range of firing rates due to direct spark ignition.
- Multi-Fuel Capabilities: Easily switches between natural gas and propane without internal modifications.

Conclusion


The Phoenix TH Tube Fired Burner, especially when paired with the RH Exhaust Recuperator, represents a significant advancement in industrial heating solutions. Its innovative design enhances heat transfer and temperature uniformity while offering substantial energy savings and emission reductions. For industries aiming to optimize efficiency, reliability, and environmental responsibility, the TH burner system stands as an exceptional choice.

Combustion Technology, LLC
http://combustion-tech.net
800-327-1831

Combustion Technology Offers Stock, Drop-In Replacement for Eclipse VERI-FLAME Burner Control

Drop-In Replacement for Eclipse VERI-FLAME Burner Control

Are you searching for a reliable replacement for the discontinued Eclipse VERI-FLAME Burner Control? Look no further than Combustion Technology, LLC's innovative drop-in solution. This cutting-edge burner control system seamlessly replaces the VERI-FLAME, offering unparalleled performance and compatibility for industrial combustion applications.

Form, Fit, and Function Match


Combustion Technology's replacement burner control matches the VERI-FLAME in form, fit, and function, ensuring a hassle-free transition for your existing equipment. Engineers and technicians can easily install this drop-in replacement without modifications to their current setup, saving time and resources during the upgrade process.

Large Inventory Available for Immediate Shipment


With a large inventory in stock, the company can provide same-day shipment, minimizing downtime for businesses that rely on prompt replacement of critical components. This ready availability is crucial for companies that cannot afford delays in their operations, ensuring they can keep their systems running smoothly without interruption.

Manufactured by the Original Equipment Maker


What sets Combustion Technology's replacement apart is its authentic pedigree. The same company that produced the discontinued VERI-FLAME now manufactures this advanced replacement. This unique connection guarantees the highest quality standards and maintains the legacy of excellence associated with the original product.

Enhanced Features for Optimal Combustion Control


While maintaining compatibility with existing systems, Combustion Technology's replacement introduces modern enhancements to improve overall performance:
  1. Advanced flame detection technology for increased reliability
  2. Improved safety features to meet current industry standards
  3. Enhanced diagnostic capabilities for easier troubleshooting
  4. Increased energy efficiency to reduce operational costs

Seamless Integration and Minimal Downtime


Upgrading to Combustion Technology's VERI-FLAME replacement minimizes production downtime. The drop-in design allows for quick installation, reducing the time your equipment remains offline. This efficient transition ensures your industrial processes continue with minimal interruption.

Industry-Leading Support and Warranty


Combustion Technology, LLC backs its replacement burner control with comprehensive technical support and an industry-leading warranty. Their team of experienced professionals stands ready to assist with installation, configuration, and ongoing maintenance to maximize the longevity and performance of your combustion control system.

The Smart Choice for VERI-FLAME Replacement


For industries relying on precise combustion control, Combustion Technology's drop-in replacement for the Eclipse VERI-FLAME Burner Control offers an unbeatable solution. With its perfect form, fit, and function match and the assurance of being manufactured by the original equipment maker, this replacement stands out as the intelligent choice for upgrading your combustion control systems.

Keep the discontinuation of the VERI-FLAME and keep your operations from being held back. Embrace the future of combustion technology with Combustion Technology, LLC's superior drop-in replacement and experience the difference in performance, reliability, and efficiency.

Call Combustion Technology, LLC  at 800-327-1831 now to order!