What Pressure Range Should I Choose?

What Does It Mean?

2-32 psi means that as long as the difference in pressure between the two ports on the valve is greater than 2 psi and less than 32 psi, the flow will be within 5% of the rated flow. It's important to note that it's the difference that matters: if the red port is at a gauge pressure of 312 and the blue port is at 300, the flow will be exactly the same as if they were 62 and 50 respectively. The port nearest the inlet should have the red strap and should have the higher pressure.

A Little Background

A flow limiter is a device which normally has a fixed resistance up to some starting pressure, and thereafter changes resistance as needed to maintain a constant flow until a maximum pressure is reached, after which the flow is again like a fixed resistance.

So What Range Should I Choose?

It's important to note that after the maximum regulated pressure the flow goes up proportionally to the square root of the pressure difference. Thus at 10% more pressure the flow will only have increased about 5%, and at 20% more pressure only about 10%. Thus it's normally OK to use the 3-32 pressure range up to around 40 psi. If the pump pressure is over 40 psi, then probably it's still possible to use 2-32 for most of the system, with 5-60 only being used at the terminals nearest to the pump. To actually figure out how near the pump requires knowing the pressure losses in the headers. With variable speed systems using Autoflow, it's common to place the sensor for controlling the pump across the index circuit (the circuit with the least surplus pressure differential), so the pressure difference across any circuit in the building will never go higher than at maximum load. Thus if we take the pressure supplied by the pump and subtract the losses in the main piping until it reaches 40 psi, that's where we would switch from the 5-60 range to the 2-32 range.

Just to clarify about the illustration, it's an over-simplified building showing one terminal per branch. The graph on the left is the pressure difference between the supply and return headers shown as the distance between the green or red line and the black line at any point along the building. The green line represents maximum load, and the red line represents a reduced load with about 40% of maximum for the total flow (perhaps 70% thermal load).

Video Challenge Series: Get to Know Rich Eberle

With social distancing keeping us apart, we challenged IMI Hydronic team members to connect with customers by creating a video to share their favorite activities and IMI products.

Here’s the first in the IMI Flow Design series, from sales manager Rich Eberle, with 24+ years in the HVAC industry and a passion for cooking. Like the quality ingredients that make a delicious meal, Rich knows you need good products for an optimal HVAC system. Products like IMI Flow Design’s flex hoses, with EDPM core, stainless steel braid, stainless steel ferrule and all-brass end connections. No upcharge for stainless steel, no o-rings or washers to lose on site.

Take a look at Rich’s video, go to to learn more about our hoses or reach out to Rich for help getting them on your next job site.

Take a Look at Our Complete Product Line


For a quick look at IMI Flow Design’s complete product line, check out our new Product Map.



There you’ll find photos and descriptions of our pressure independent balancing and control valve, automatic balancing valves, manual balancing valves, lead-free balancing valves, brass and steel hookups, standard kits and hoses.

A great selling tool or just a convenient way to see all the resources we bring to help design optimal hydronic systems for your HVAC applications.

Download the Product Map here.


And to learn about any specific product, please reach out to us at ask.fdi@imi-hydronic.com.

Share Your Customer Success Story with IMI Flow Design

At IMI Hydronic Engineering, we’re known for strong partnerships with sales reps and customers alike. Recently, BTSE Heating|Biomass & Solid Fuel Systems, a Welsh installer of oil boilers and fuel systems, paid tribute to their collaboration with our colleagues at IMI Hydronic UK. In song! Take a listen below to Takeover IMI, part of BTSE’s week-long takeover of UK Social Media.

We listened, and started thinking about our successes with all of you.

So, show us how IMI Hydronic Engineering North America helps power HVAC projects for your customers. Not musically inclined like BTSE? No worries. Think creatively to share your story of success with IMI Flow Design: in images, verse, whatever captures your imagination. Then, send them to Armando Reyes, Head of Sales, and watch LinkedIn for stories of shared pride, how we succeed together for your customers.

Soham Neupane Enhances Hydronic Training for the Sales Team and Customers

Welcome, Soham Neupane, new Hydronic Training Manager for IMI Hydronic Engineering North America, bringing additional expertise to IMI Hydronic’s deep knowledge and strength in hydronic systems. Soham will train the sales force on hydronic products, from a systems solutions strategy to help sales reps and their customers design energy efficient, optimized hydronic balancing solutions for their HVAC system applications.

Soham comes to IMI from HVAC Manufacturing in Athens, Texas, where he provided design services, as well as pre- and post-sales technical support to project engineers, contractors and others on VRF, VAV systems with integrated controls and hydronics. Soham’s cradle-to-grave experience encompassed everything from the design and quotation phase to final approval and delivery of HVAC equipment to supervision of product installations for commercial projects.

Equally comprehensive is Soham’s approach to training. “My goal with our customers is not just to deliver product information, but to deliver an experience,” he says. And he’ll bring that philosophy to all customer trainings, including management of IMI Hydronic Engineering’s new webinar series, as well as working one-on-one with sales reps and their customers. As a key member of the Sales, Marketing, Customer Service and Product Development team, Soham will also serve as the commercial product expert to respond to customer questions for IMI Hydronic Engineering in North America.

“With Soham’s thorough understanding of HVAC systems, passion for solving customer problems and experiential approach, training will now be even more closely aligned with IMI Hydronic’s knowledge sharing philosophy,” noted Bhumika Lathia, Head of Strategic Marketing and Business Development, Americas.

Soham holds a master’s degree in Mechanical Engineering from the University of Kansas.

Jenna Bauer Joins the Team to Elevate Customer Service

IMI Hydronic Engineering North America welcomes Jenna Bauer as our new Customer Service Manager. Jenna brings significant experience and expertise to IMI Hydronic, gained over six years in customer support roles with increasing responsibilities at IMI Precision in Littleton, Colorado.

In her new role, Jenna serves as an internal strategic advocate for our sales rep network, hearing their needs and leading the customer service team to take immediate action in response. This involves not only refining some customer service policies and procedures but, most importantly, continuing to build bridges across IMI Hydronic departments for overall better communication, seamless operation and elimination of silos. Her extensive experience with JDE while at IMI Precision will also help accelerate mastery of the ERP system in Dallas.

Jenna is eager to take on the challenges. “Delighting customers, our business partners, is most rewarding for me,” she said. “There will be hills to climb, but I look forward to each challenge. That’s the mentality that I’m sharing with our entire team, and how we will grow and succeed with IMI Hydronic I look forward to an exciting future!”

Already, Jenna is in problem-solving mode, revising some processes to address the reduction of team members in the office as a result of the work-from-home adaptations that the pandemic has imposed not only on us but our sales reps and their customers. And, with a Marketing degree from the University of Colorado Denver, Jenna is also looking forward to working with our sales reps’ marketing departments as a liaison in the near future.

Armando Reyes, Head of Sales, views Jenna’s hire as an opportunity to focus exclusively on our sales reps and their customers in the field. “With Jenna based in our Dallas HQ, we now have a partner internally to ensure focus on our sales reps’ day-to-day needs. The IMI Flow Design sales team and I can count on her and the customer service team to address our sales reps’ immediate needs while we concentrate on working together to win the next big project.”