by MrPEX Systems MrPEX Systems

Introducing Radiant Wood Track

Product Highlight featuring Radiant Wood Track. MrPEX Systems now offers a Radiant Wood Track System for the use of 3/8″ PEX tubing to minimize additional floor height. The MrPEX Radiant Wood Track comes in three standard panels, Run Panel, Turn-Around Panel, and Manifold Panel. Each panel is 12″ x 48″ x 5/8″ and are marked for easy and optimal cutting to fit any layout. This is a great product to combine hardwood floors with radiant floor heating!

Click here to download the product data sheet

by MrPEX Systems MrPEX Systems

Tomas Lenman Receives Prestigious PPI Award

May 2017; Tomas “MrPEX” Lenman was recognized by PPI ( Plastics Pipe Institute) with a 35 years of dedication and commitment in establishing the North American PEX Industry through technical leadership award. Although Tomas wasn’t able to accept this award in person, he was happy to pose for a picture when it was handed to him! Tomas, now retired, spends his summers in Sweden relaxing at his lake-place. When not there, he and his wife enjoy spending time traveling together! Tomas is a true inspiration of perseverance and accomplishment and will be missed in the PEX industry!

by Mr.Pex Mr.Pex

Tomas Retires

Tomas “Mr.PEX” Lenman, Owner & Founder MrPEX® Systems, Retires.

Tomas “MrPEX” Lenman

In 1971, when Tom Lenman began his career as a development engineer at Wirsbo in Sweden, he never imagined he would stay in the same trade for a lifetime. After learning to build airplanes at the Royal Institute of Technology, his interest shifted to development of PEX Tubing for hot water applications. Virtually a new arena for plastics, it required many months of research to find suitable material designs, additives, optimizing properties, etc. Even more challenging was getting the material approved for its intended applications. Authorities were skeptical and required extensive testing. Since European cooperation between countries was only an idea at that time, every country needed to be approached separately for approval.

“Willis Carrier is often called the “father of modern air conditioning.”  In the same regard, Tomas Lenman should be credited as the man who introduced North America to PEX tubing starting back in the 1980s.

At that time, PEX was viewed somewhat skeptically by many heating pros, including me, who thought that any tubing used in a heating system had to be metal. Tomas’s efforts to educate North American about the technology and quality control involved in producing PEX tubing changed this attitude, and cultivated a North American market that now measures annual sales of PEX by the billions of feet.

Over the years Tomas has graciously helped me with specific inquiries about PEX.  I have great admiration for his technical understanding and factual unbiased responses to my questions.

Tomas, you will also be “Mr Pex” in my mind. My sincerest thanks for the outstanding contributions you’ve made to the North American heating, cooling, and plumbing industry.” – Sincerely, John Siegenthaler

At the same time, Shell Chemical invented a new Polymer in the United States: Polybutylene. After early success in the US, they approached the European market. PEX and PB were bidding the approval of committees in several different countries. For PEX (and Wirsbo), Tomas was the representative, while Shell Chemical normally came to meetings with several constituents, under the oversight of Steve Pregun. Steve would typically introduce Tomas as “Mr. PEX” to new colleagues and meeting attendees. The nickname stuck and has followed Tomas ever since.

By the early 1980’s, Tomas was working on the US PEX standards, now known as ASTM F876 & F877. Meetings took place 3 to 4 times per year. Shell Chemical had succeeded in developing an ASTM standard specification for Polybutylene (PB) a few years earlier. At this point, they had 6 strong Polybutylene tubing manufacturers attending the PEX standardization committees. Tomas had some support from PE raw material manufacturers and professional code developers, but realized the PB majority would be able to raise unlimited objections and delay the PEX standard indefinitely. The European and International (ISO) standards had different ways to evaluate and predict long-term strength of Plastic Pipes – compared to US standards (read ASTM D 2837). Shell’s own data, as provided to ISO and several European committees, clearly displayed a “knee” in the long-term strength data at higher temperatures, (a “knee” indicates a clear point of extrapolated failure) as well as independent data from European testing institutes (including such tests paid by Wirsbo). With this data presented to ASTM committees, they would have no choice, but to change the pressure rating or the wall thickness of the Polybutylene pipes (with a lot of installed PB Tubing becoming disapproved). Tomas showed the data to Steve Pregun and spoke of his intention to start a new ASTM project to revise the PB stress rating. After negotiating, the two ASTM PEX Standards were published 6 months later in the fall of 1984. Tomas had already arrived in the United States in August of that same year to start the subsidiary Wirsbo Company.

“I was in business for a year and a half in December 1990 when Tomas Lenman invited me to travel to Sweden with a group of industry writers to be a part of Wirsbo’s Ten Times Around The World celebration. They had sold that much PEX pipe by the end of that year, and Thomas Lenman had played a large part in its development.

I knew little about radiant heating that year, other than what I had gleaned from my old heating books, and those systems were of copper tubing, not this remarkable new plastic that Tomas Lenman was introducing to the United States.

We toured a bit of Stockholm on that trip and then continued on by bus to the celebration, where I listened to Tomas Engel, the man who had invented PEX. I had never heard of him at the time and I smile now at the thought that I once was in the same room with that brilliant man.

Tomas Lenman moved on to other challenges and other companies as the years went by. He always excelled. Along the way, I had many questions for him over the years, and many of those questions arrived wearing boxing gloves. You see I was a brash young man back then and I had not yet learned the habit of just shutting up and listening to those who were older, and in Tomas Lenman’s case, certainly smarter than I was. I wish I had been a better student for him.

So as you prepare to retire, I say thank you, sir. Thank you for your patience with me. And thank you for all that you’ve done for this wonderful industry.”  –Dan Holohan

Tomas Lenman can also add “author” to his list of accomplishments. His book “Water and Pipes” has been published in three languages and the US version was distributed twice in 1984-85. The book mirrored what he learned on the subject up to that time. Trade magazines gave it fair exposure and gave Wirsbo name recognition. In the late 80’s a “Wirsbo System” was more known to the trade than “Under Floor Heating System”. The content of the book is available on the MrPEX® website at In 1986, they began publishing “World of Wirsbo” 4 times a year. It was about successful radiant heating projects and provided the nuts and bolts on how they work.

In the early 90’s Wirsbo owned close to 50% of the radiant floor heating market share; the market penetration increased rapidly and several new system suppliers entered. HRHA (Hydronic Radiant Heating Association) was formed, but only survived a couple years. Tomas could not agree with the majority: to downgrade the importance of oxygen barriers on polymer tubing for heating. Wirsbo only supplied tubing with Oxygen Diffusion Barrier to the market, but some competitors did not. A huge amount of European experience and research was challenged and dismissed by many for a few years. Some of you remember trade magazine articles like “Looking for Elvis” (looking for systems with corrosion problems due to oxygen in the systems). Fortunately, “Elvis” was soon found and only a limited number of systems suffered from the bad design.

At the time, Finland based Uponor, was producing plastic pipes for cold water distribution, sewer applications and gas distribution. Uponor acquired Hewing (Germany) and Wirsbo (Sweden) in 1988, the two dominant manufacturers of PEX Tubing in the Western hemisphere. Over the next decade, Uponor continued acquisitions of companies active in hot water distribution, but also sold off its interests in traditional (cold water or gas) plastic pipes applications. A total transformation of product lines took place, bringing strength to their trade names in the plumbing and heating field. Their marketing strategy was Multi-brand, Multi-channel Distribution, which was successful for many years. Around 2006, it was astonishing when the group decided to unify operations under the single trade name, “Uponor.” Well established trade names are considered valuable assets and often booked on corporate balance sheets. Trade names such as Wirsbo, Velta and Polytherm were scrapped in favor of the virtually unknown Uponor (at least in North America).

In the fall of 2000, Tomas learned that the LK Group in Sweden had hired Lennart Agren to setup a new PEX production plant. Tomas met with Lennart and LK Group at the ISH show in Frankfurt, March 2001. The combination of a fast production process, adding polymer layers (such as oxygen barriers, etc.) and curing to optimal crosslinking in line, while at the same time (partly) orienting the molecules around the perimeter of the tubing resulted in a winning concept; a fast PEX (a process resulting in a tubing with exceptional flexibility and still stronger than most). Tomas gained the exclusive distribution rights to the US market, terminating his then current employment (Roth USA), and started MrPEX® Systems in June 2001. After a year of hard work and preparation, the product line launched in the spring of 2002.

Once again, contenders tried to delay and stop the introduction. This time it was not Polybutylene competition, but existing PEX manufacturers who argued that MrPEX® Tubing should meet additional testing requirements, such as testing the degree of molecular orientation in the tubing. Since Tomas knew the important crucial parameters for other PEX manufacturing processes that lacked prescribed testing, the extra requirements were dismissed and MrPEX® was approved.

Tubing in Earthquake safe high voltage transformers: ABB (Asea / Brown Bowery) used water to chill huge transformers. Flexible 2” PEX Tubing, pre-formed in an S-shape, led the water to and from the hanging transformers, making the construction earthquake- safe. As he retires and looks back at his professional life, Tomas says he feels satisfaction. “It has been a great journey developing the PEX material, working on its applications and getting it approved for plumbing and heating in many countries. At the same time the most gratification in life is received through interaction with people. Thank you, PEOPLE! Thank you for listening, thank you for friendship, thank you for believing (in PEX and in me), and most of all, thank you for purchasing MrPEX® products!”

Did you Know?

Did you know there are many other applications for PEX? A few examples are:

Ski-soles: in Cervinia, Italy, there is a straight downhill track called “The Flying Kilometer” where competitions take place every year. A new world record was set there in 1976. The ski’s soles used were made of PEX Tubing, slit open and chilled down flat. More than half of the downhill medals at the Innsbruck 1976 Winter Olympics went to Wirsbo’s PEX soles.

Tubing for blood: A major dialysis machine manufacturer used custom pre-formed 1/4“PEX tubing between the machine’s different chambers. The price per weight was higher than that of gold.

Tubing in Earthquake safe high voltage transformers: ABB (Asea / Brown Bowery) used water to chill huge transformers. Flexible 2” PEX Tubing, pre-formed in an S-shape, led the water to and from the hanging transformers, making the construction earthquake- safe.

by MrPEX Systems MrPEX Systems


MRPX 2015 Plumbing Full-Page Ad

We are known for our very flexible and durable MrPEX Barrier Pipe for Radiant and Snowmelt Systems, and we now offer a complete PEXa plumbing system with the same great product, offering some… real advantages as compared to conventional copper pipe systems.

The MrPEX POTABLE PEXa tubing is offered in red, white & blue, and in coils or sticks, with complete accessories and tools! The fitting system utilizes Lead Free Brass F1807 and PPSU F2159 profile together with a stainless steel PEX press sleeve.


by Mr.Pex Mr.Pex

MrPEX®Stainless Manifold

manifold-1MrPEX Stainless Steel manifolds achieve the highest level of long term corrosion resistance by using a bright annealed high-grade stainless steel with high nickel content. This creates a stable material structure with low levels of ferrite and magnetism. To eliminate the possibility of contact corrosion, all fittings connected to the manifold are nickel-plated.

The manifolds are fully assembled, ready for mounting, the supply side feature adjustable flow-meters for flows up to 1.45 gpm per loop, and the return side has balancing on/off valves, in accordance with DIN EN 1264-4. The adjustable flow-meter allows for a positive shut-off and the manual plastic cap on the return valve can be removed to accommodate a valve actuator. The return balancing valve disc is designed to enable exact adjustments of small flows while still being able to handle large flows with minimal resistance. The combined branch Cv value is 1.64 gpm and the manifold body accommodates flows up to 14 gpm.

by Mr.Pex Mr.Pex


Retrofit system for existing applications

retro-1RetroPanel is a perfect retrofit product for applications where comfort, efficiency, system height, and performance is key. It uses the combination of metal on the surface, with high thermal conductivity and built-in insulation underneath, to maximize the heat output at low water temperatures. The metal surface also promotes an even temperature distribution across the floor, minimizing cold spots. The low thermal mass allows for a quick response to changing load requirements. RetroPanel is unmatched in its ability to optimize system efficiency.

The RetroPanel is a floating system and the panels are easily installed by snapping them together to form a uniform layer over top of either a concrete slab or wood sub-floor. The panels are arranged with the tubing channels (grooves) of the RetroPanels. The metal tubing shields and return panel coves are then attached over the tubing. Finally, the finished floor is then installed directly over the RetroPanel surface to complete the installation.

Just a few of RetroPanel’s benefits:

  • Snaps together – labor saving
  • 1/2″ tubing – longer loops, fewer circuits
  • Tubing is protected against damage
  • Pre-insulated and low profile (3/4″) – great for retrofits
  • Highly conductive surface – high heat output and even temperature distribution
  • Water-resistant – great for basements
  • Easy to cut if necessary to fit tight spaces and around obstructions
  • Low thermal mass – quick output response

by Mr.Pex Mr.Pex


retroMrPEX Systems is introducing a new style extruded aluminum heat transfer plate for 3/8” or ½” PEX tubing in the same plate. DuoTrack is 48” long x 3.75” wide with pre-punched holes featuring a double grove for two sizes of PEX tubing. This reduces inventory, space and cost.

DuoTrack plates are low mass and have a faster response time, higher output, and lower water temperatures requirement as compared to joist heating duo-trackwithout plates. Give it a try next time you have a suspended application.