Heat your pool in 1/3rd the time at 1/3rd the cost!


Traditional Pool Plumbing
High Heating Costs

Flowreversal pool illustrations shows how efficient it is for heating.

Flowreversal Pool Plumbing
Low Heating Costs

The Flowreversal Module X-Body Simulator eBook


With this Flowreversal eBook, you will learn how to implement Mark Urban's Flowreversal Technology to heat your pool in 1/3rd the time and at 1/3rd the cost by using the “Palmer Flowreversal Module X-Body Simulator.”  

This is a pool plumbing work around design to accomplish Flowreversal energy savings created by Edward G. Palmer.  This design uses standard industry valves to accomplish swimming pool flowreversal, because Mark Urban's valves and their parts are no longer available.

You can build and install Flowreversal for your pool with the information contained in this low-cost eBook. Or, you can purchased a "Module Kit" to save yourself and your plumber time and money. The “Module Kit” comes with all the parts you need, a detailed 17-page install guide along with labels to identify all the valve inputs and outputs to eliminate plumbing confusion. The "Module Kit” can literally pay for itself simply by eliminating confusing plumbing issues and plumber costs.  

Either way, you will save thousands of dollars in pool heating costs by creating an energy efficient swimming pool using Mark Urban’s Patented Flowreversal Pool Technology.

Mark Urban's Flowreversal Pool Heating Patent

Pool and spa heating and cooling

Krumhansl; Mark U. (Tustin, CA)

United States Patent 4,621,613          November 11, 1986


Patent Abstract

The efficiency with which the water in pools and spas may be heated is greatly improved by circulating water through a heat exchanger such that heated water is introduced at or near the lowest point in the body of pool or spa water and by removing water to be heated from a point near the surface notwithstanding that the heated water rises to form a warm layer at the surface [Flowreversal].

When the body of water is heated to a selected temperature, the [water] flow direction is reversed so that water is withdrawn from the low point and, after heating, is returned to a point nearer the surface [Normal pool water flow].

That method [being able to reverse water flow] has the advantage that it can be practiced with conventional pool and spa plumbing systems with minimum modification to permit a reversal of pool and spa inlet and outlet opening connection to the external water-cleaning conduit. Water flow and control in the external circuit remains the same. [Pool] System operation and practice of the [Flowreversal] method is enhanced by the inclusion of a solar energy collector and valves of unique design. [Special X-Body and T-Body] valves employ special cores [mid-vane diverters] that enable a minimal modification of the swimming pool’s existing support system].

Patent Background Discussion

It is customary to clean the water in swimming pools and spas by withdrawing water from the lowest point in the pool or spa, filtering it, and then returning it to the pool or spa at a point just below the remaining water's surface. In the case of a swimming pool, the system usually includes a "skimmer" for drawing a portion of the circulating water from the upper surface of the body of water. That arrangement facilitates cleaning of the water, and is almost universally employed. In the case of the spa, the inlet is usually placed somewhat lower, and is made the inlet for air as well as water. The air and water are often combined in an aspirating venturi or in a Jacuzzi valve. That arrangement is used to admit a high velocity stream of water and air bubbles as well as being selected to facilitate cleaning of the water.

Thus it is that swimming pools and spas are plumbed and a circulating pump is provided to withdraw water from the low point in the body of pool or spa water and to return it at a higher point, usually near the surface of the body of water. The water circuit includes the outlet, a pump, a filter and the inlet, in series, and the pump usually precedes the filter.

Heating of the water, if that is to be done, is accomplished in a heater unit, which is included in series in that circuit between the outlet and inlet. There may be an arrangement for bypassing the heater during intervals when the heater is not in operation, but when in operation the heater is connected in series with the cleaning circuit.

As a consequence of that arrangement, the water in pools and spas is heated by withdrawing cold water from the bottom and supplying heated water to the upper region of the pool. The warm water, being less dense, rises in the pool and the spa and cold water settles to the lower regions. That has some convenience for bathers use the water in the upper regions more than they do the lower water. However. It is found to have a very great disadvantage in that much energy is wasted when heating from the top downward, as it requires replacement of the cold water by warm water.

It is one purpose of this invention to provide methods and means for overcoming that disadvantage in large measure.

How Mark Urban plumbed his X-body and T-body valves to create a Flowreversal system in swimming pools.

Mark Urban Flowreversal Plumbing

     Heat your pool in 1/3rd the time at 1/3rd the cost!


        I met Mark Urban in person for the first time at a Tampa Pool Industry trade show in November 1987. It was a full year following Mark’s patent grant. I was working on a new solar technology for using the attic of your house for heating your swimming pool. Mark was very interested in my solar pool heater technology and offered me the opportunity to place a unit within his trade show booth. It was also the opportunity to talk to pool industry people about my energy innovation for pools. My wife and I placed a unit in our station wagon and drove down to Tampa for the pool industry convention.

         Mark was an experienced pro in the swimming pool industry and I was just a “newbie.” I thought I had a product that would “knock the socks” off of pool builders. Mark quickly took my illusion of fast success in this industry away. He informed me how difficult it had been for him, with what he felt was also a simple concept for pools. Heating pool water from the bottom up, like cooking food, should be a no-brainer, but it wasn’t!

         If you ask a pool builder if they have ever heard of Mark Urban’s Flowreversal technology for swimming pools, the odds are that over 90% will say they haven’t. This is after three decades of Mark attending industry trade shows around the nation tirelessly promoting Flowreversal technology. I now find myself in a similar position with over a quarter century promoting my solar attic technology.

         Mark’s answer to the question of why it was so difficult in the pool industry was not very flattering from a business perspective. He told me that the industry had a lot of “Neanderthals” that were closed minded and stuck in the past. That reality is coupled with the industry having an old boy’s network, which controlled distribution channels. Therefore, the industry is resistant to change, new products and to innovation. New products are often left dangling for years and acceptance of new products or technology is often forced on the industry by laws or consumer demand. Thankfully, with the Internet, consumers have more new product options and marketplaces.

         Mark Urban died on December 11, 2010 and no one has picked up his unique valve technology and manufacturing operations as of this writing. As a result, his Flowreversal technology using X-Body and T-Body valves is simply no longer available to the public or the swimming pool industry.

         Mark and I promoted each other’s products because we were in the same boat so to speak. Both of us had innovative energy technologies that could save a pool owner literally thousands of dollars. Not to mention extending the swimming pool season and drastically increasing the ability of the family to enjoy the swimming pool experience. Besides Mark’s own Flowreversal web site, the solarattic.com web site had available the most comprehensive information on Flowreversal technology and how to use it. Since Mark’s passing, I’ve had numerous inquiries into Flowreversal and how to get it or get parts for Mark’s valves. That is the main reason for developing this alternative to the unique 4-port X-body Flowreversal valve and Flowreversal System Mark Urban invented.

         So Mark did not just disclose the method of heating a pool from the bottom up, he also invented and manufactured unique valves to enable someone to actually use his new technology. Mark was an absolute genius when it came to pool hydraulics and plumbing. His valve technologies reflected this fact.

         It is the unique X-Body valve design and the Mid-Vane diverter that enabled Flowreversal to take place with minimal reconstruction of the pool support system. This eBook completely illustrates the X-Body valve design along with the T-Body valve and how they were used together in pools. I then discuss the alternative "Palmer Flowreversal Module" design that I developed. Clear graphic illustrations are provided along with flow diagrams so you can fully understand Flowreversal Technology and how to use it in your pool as a replacement for Mark Urban’s Flowreversal System, which is no longer available to the industry or to consumers directly.

patent valve dwg

Mark Urban's Mid-Vane Diverter & X-Body Valve

It was the mid-vane diverter that enabled Flowreversal Technology to take place with only a 90 degree turn of a single X-Body valve. X-Body water flow diagrams are shown next. 



Reverse flow in Mark Urban’s unique X-Body Flowreversal valve shown in this picture.

     Heat your pool in 1/3rd the time at 1/3rd the cost!


The Palmer Flowreversal Module
eBook Contents

  • Mark Urban’s Flowreversal Technology
  • Mark Urban's Flowreversal Implementation
  • The Palmer Flowreversal Module X-Body Simulator
  • The Palmer Flowreversal Module Using Standard Industry Valves
  • Easy to understand graphic illustrations of flowreversal concepts
  • Easy to understand plumbing diagrams for flowreversal installation
  • Pool Energy Saving Bonus Special - "How-To Heat a pool for $15/month"

The "Palmer Flowreversal Module" with all its PVC parts, valves, and water flow labels can be assembled and built locally using the "How To Build" guide for easy construction and building. Click the "Installation eBook" page link above for further information on purchasing a "How To Guide” to build your flowreversal module or replace an old or defective Mark Urban flowreversal valve. Mark passed away in 2010, and, as his friend, I am offering this technology to replace his valves, which are no longer available.

Flowreversal Technology Results are Astonishing!
With Mark Urban's Flowreversal Technology, You can ...

     Heat your pool in 1/3rd the time at 1/3rd the cost!

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