What is Smart Recirculation Control?

Smart Hot Water Recirculating Pump Controller

This controller turns any home or business plumbing system with a dedicated circulating line, tank water heater, and hot water circulating pump into an on-demand hot water system. 

Smart Recirculation Control from Leridian Dynamics


On demand hot water recirculation control system diagram animated image

Turns any recirculation pump into an on-demand recirculation pump. 

  • Flow-based hot water pump controller.
  • Unique dual temperature sensor design.
  • Reduces pump run time to less than 30 minutes a day. **
  • Includes built-in pump timer capability.
  • Easily configure with your Android or iPhone smart device. 


The Smart Recirculation Control is an On-Demand smart hot water recirculating pump controller for homes with a dedicated recirculation loop (if you don’t have a dedicated recirculation loop check out our Smart Thermostatic Control).  This control works best with tank water heaters. If you have a tankless water heater check out our Smart Aquastat Control.

The Smart Recirculation Control controller is designed to sense when hot water is drawn from any plumbing fixture and to run the recirculation pump until the water in the recirculation loop is hot. 

The microprocessor-based design monitors the temperature of the water in the loop using a unique dual temperature sensor design to ensure the water in the loop stays hot while hot water is being used.

On-Demand Operation

To operate go to any faucet and turn the hot water on then off.  The Smart Recirculation Control senses this minimal draw, checks the water temperature in the loop, and if necessary, starts the pump running.  Within seconds the water loop is hot and you are able to draw hot water.

Because the Smart Recirculation Control uses the demand of hot water to know when to run the pump, it works even when your washing machine or dishwasher needs hot water.  Unlike other on-demand hot water systems, there is no need to install switches or sensors at each faucet location and run wires, maintain wireless transceivers, or replace batteries.

Smart Timers and Vacation Mode

The Smart Recirculation Control also has a set of “Smart Timers” that can be used to heat the recirculation loop on a schedule.  But because of the dual temperature sensor design, the Smart Recirculation Control only runs the pump until the loop is heated up.

The “Smart Timers” are disabled if the controller doesn’t sense a hot water draw within 24 hours.  So if you go on vacation and forget to manually disable them, no worries, they will turn themselves off and re-enable as soon as it senses a hot water draw.  The “Smart Timers” are set via your Android or iPhone smart device. The on-demand functionality is still in effect outside of the timers.

The Smart Recirculation Control is all you need to efficiently control your hot water pump.  Because of the dual temperature sensor design, it doesn’t matter what temperature is set on your water heater, it uses the difference to know when to turn the pump on and off.  Flow meter sensitivity and temperature difference settings are easily set with your Android or iPhone smart device.

The Smart Recirculation Control Helps Save Your Plumbing. 

Running a recirculation pump continuously will exellerate the erosion of the copper piping in your home causing pin-hole leaks requiring replacement of the entire hot water supply system and water damage to your home. This is no small expense.

The Smart Recirculation Control helps avoid this expense by turning your recirculation pump into an on-demand hot water system.  Running a pump “on demand” typically reduces pump run time to less than 45 minutes a day!

Start saving water ($), energy ($$), and your plumbing ($$$) by installing Smart Recirculation Control!

Smart Recirculation Control works with all 110/220 VAC makes and models of pumps up to 1/2 hp and with other plug and socket types around the world with adapters appropriate for your country. Our Smart Recirculation Control family of products is made with a Type B plug and socket.

* of the US and foreign parts, it’s hard to obtain US-made semiconductors
** typical usage for a household of 4 (link to log file example)
Based on 32 reviews
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Showing 30 of 32 reviews (5 star). See all 32 reviews
  1. Art U. (verified owner)

    Here’s my situation – new heat pump water heater, fairly large house with hot water recirculation plumbing. You really shouldn’t use a heat pump water heater with recirculation – the heat pump will just end up running constantly. So, I purchased this controller. It was very easy to install – I was already redoing the plumbing for the new water heater, so adding the flow sensor was easy. Wiring was easy, connecting the unit to my phone app was easy, and set was easy. And it’s working exactly as it should! I still get quick hot water throughout the house when needed, and the water heater isn’t running when hot water isn’t needed. I’m very happy with this Leridian Dynamics controller!

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  2. Branko H. (verified owner)

    I have a Rheem hybrid water heater. The nuance of such a water heater is that they do not recommend a circulation pump when using the Energy Saver mode. The programming and electronics don’t like recirculation pumps. However, the Smart Recirc Control 32 helps dramatically by only recirculating water when needed. It also does not run all the time and therefore the inlet to the hybrid water heater stays at a reasonable temperature to not confuse the electronics and programming. I have found that I’m saving energy costs by implementing this smart control with my hybrid water heater. In some ways I have cheated the programming and I still have recirculation of water and hence on-demand hot water. I would recommend on long recirculation runs that the temperature probe prior to the pump is placed as far upstream as possible. This ensures that hot water does not come close to the inlet of the hybrid hot water heater. Great product!!

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  3. Dennis V. (verified owner)

    I just recently installed this unit in my shop/apartment, replacing another brand which had failed. I am very pleased with the operation and performance thus far. It is obviously well thought out and implemented. I do have the thermocouples attached directly to PEX (with some wraps of conductive foil underneath), and as predicted in the instructions the response lags due to insulating characteristics of PEX. I plan on purchasing a 2nd unit for a new house I am building, and there I will be sure to have copper stubs to attach the thermocouples to. The programability of various parameters using the app works very well. Excellent product.

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  4. Gregory D. (verified owner)

    The system was straightforward to set up, and so far (one month since installation), it is working as promised. We’re looking forward to how this may reduce our gas bill compared to our old system that used a timer, where the circulation pump ran continuous for many hours during the day.

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  5. David T. (verified owner)

    Absolutely amazing product. With so many expensive hot water recirc pump solutions out there (ones that also might not meet the needs of the build, GPM wise) this solution allows you to simply use ‘the right pump for the job’ and the brains/logic of this device takes care of the rest. Not only can you buy this along with a better pump and still be cheaper than most ‘high end hot water recirc solutions’, but if/when the pump goes, it’s a simple ‘off the shelf’ pump swap instead of awaiting for a special order pump to arrive. The bluetooth works flawlessly for onsite maintenance and programming, remote Wifi would be a nice added feature for remote tweaking/programming, but understandably would increase the costs of the unit. Very impressed with the system so far.

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    Home Page Review
  6. William R. (verified owner)

    This product is simply genius. It revolutionizes the hot water on demand market. Circulating pumps have been sold for years bragging instant hot water and little water waist while waiting for hot water. When we bought this house that had one installed, I was very happy to save water and have instant hot water. That was until I did some research that revealed I am using massive energy by running the pump 24-7 and energy to keep that water hot in the line. All that waist for the convivence having instant hot water a few times a day. Sure, it did save some water but a very high cost to me and the environment. So, I added a timer to my pump to turn it on morning and evenings when I was more likely to use hot water. Better, but still not that efficient. I have searched for remote on demand systems that I could add to be more efficient, but they all had issues like hard to install, hard to remember if it was left on or off, WIFI or Bluetooth issues, need to use apps or find a good location(s) for control(s). Then I ran across this product. Are you kidding me! No fumbling with buttons or apps – just turn the hot water on for a second to get the pump pumping. Brilliant!! Only pumps when you ask for it and need it. This checks all of the environmental boxes. Absolutely saves water. Use the absolute minimum energy to deliver the hot water – ONLY when needed. The Smart control 32 should be required with every recirculating pump sold.

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    Home Page Review
  7. Robert F. (verified owner)

    I am a aerospace instrumentation engineer. My worst nightmare is equipment, software, solutions that don’t work. This is not one of those. The Smart Recirculation Control assembled, started, and ran, as plug and play as is possible. The perfect solution for me. I want to help with marketing if I can. A great product…

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  8. Paul N. (verified owner)

    Easy install and works great.
    Bluetooth app is simple to use

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  9. lee d. (verified owner)

    This is just what I was looking for so I could get hot water instantly on the other end of my house without the pump running constantly. I ran a return line and used my own pump and it works flawlessly! Its easy to program and gives you all the control you could want. I have already told neighbors and customers about it. Before I bought it I had several questions so I called in and they were able to answer any and all questions I had without hesitation.

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  10. Mike T. (verified owner)

    System is working great. I have a OnDemand heater with a return loop that had a timer on it. Installing the flow meter and thermostats was simple for my system (Pex Piping). There are multiple software versions that you can run in the Smart control. I started with the Smart Thermostatic Control Tankless and didn’t like the cold spikes I was getting. I talked to a very help full service department and it was recommended that I change to the Smart Aquastat Control software. Iam thrilled with the results. There is occasionally a small temp change while taking shower now, with a OnDemand heater this is fantastic. It was easy to download the new software and I unplugged one thermostat. I only run on the demand feature now, it takes a crack of a faucet on and off and 20 seconds later hot water is available this is with a 70′ run. The advanced setting in the software allowed me to fine tune the system the way I want it. Iam very pleased with the product and support.

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  11. Stephen D. (verified owner)

    Excellent product. I have nothing to compare to but, this controller works great. Before I purchased the unit I spent a lot of time researching all of my options and this unit fit exactly what I wanted. I had to start from scratch, meaning I did not have a return pipe back to my electric hot water tank. So to go along with me spending some time installing that pipe I wanted a controller that was not to crazy but a controller that was easy to install. On top of that the APP works great also.
    I sent an email to the company not knowing that if I would get any response, well the president of the company answer my email in a timely manner, not only once but twice. That made my mine up. Thank you David Lehrian

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  12. Kaelin S. (verified owner)

    Ideal in concept, flawless in execution.

    The key issue of having a hot water loop system is how the system “knows” when you want hot water so it can trigger the pump. I’m familiar with several ways to do this:
    *Manual switch at the pump
    *Timer at the pump
    *Remote buttons at bathrooms or sinks (wired or wireless)
    *Sensor on bathroom doors (turns on when opened)
    *Motion sensor in bathrooms or kitchen
    *Motion sensors under the cabinet toe kicks

    But there is *already* a mechanism by which the system knows you want hot water: when you, from a faucet, run the hot water. This system eliminates all timers, switches, motion sensors, etc. by this simple yet profound observation, replacing them with a much superior sensor – a flow meter on the water line going into your hot water tank.

    Additionally, this system also supplies timely hot water to other fixtures that aren’t normally served well by timers, motion sensors or door sensors: the clothes and dish washers. Anything using hot water can trigger this system.

    Additionally, it knows when to turn the pump off. This is critical for energy and water savings. The pump can only bring the temperature of the hot water loop up to within a few degrees of the water in the tank. Once that occurs, the pump should be shut off. It is not as simple as checking the water temperature in the loop for a static target temperature because as hot water is used from the tank, the temperature can begin to fall and the pump wouldn’t turn off until the hot water usage was stopped and the hot water heater recovered (which is harder for the hot water heater to do while the pump is on!). So this system monitors *two* temperatures – the hot water leaving the tank, and the hot water returning to the tank from the loop. The two temperatures are used to calculate a the temperature *difference*. Once temperature in the loop is within a few degrees of the tank, the pump is automatically turned off until the temperature difference increases *and* usage of hot water continues. ALL of that is exactly what this system does.

    The result is that the pump runs exactly when you need it to, but not a minute more. And the homeowner experience (my family and I) is sublime. I both have hot water when I want it AND save money not running the pump too much or too little. Running it too little results in hot water users running water down the drain. Keep in mind that as a user runs water from the hot faucet down the drain, even if it’s cold, cold water is running into your tank, cooling it down.

    If the hot water loop is completely cold – like early in the morning when all night long its saved you money by not running the pump and by conserving hot water – I simply turn on the hot water faucet for literally slightly less than a second on my way toward more pressing needs. By the time I’m ready for hot water on a cold winter morning, it’s *right there*.

    For those that just absolutely need the hot water pump run at a specific time, you’re still covered. The app allows you to program several run times if you wish. Personally, even though I get up at a regular time during the work week, I *still* don’t use the timers because the flow meter is such an effective mechanism to indicate hot water demand.

    Every house with a hot water tank should be built with a loop and the pump controlled this way.

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    Home Page Review
  13. Bruce C. (verified owner)

    This is an amazing product that helps you save water and energy while providing the luxury of immediate hot water at your fingertips. The use of two thermocouples and a flow sensor is elegantly simple and genius. I would not consider a hot water recirculation loop system without the Leridian control system.

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  14. Michael T. (verified owner)

    Unit was easy to install and set up. It works perfectly and the wife really enjoys that there is now hot water at the kitchen faucet.

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  15. Emiro U. (verified owner)

    I am very pleased with the unit. Works as advertised. I installed it myself and didn’t need a plumber. Instructions were clear and easy to follow.
    My pump was over heating when I had it on a timer. Now the pump runs only when I need it and I always have hot water. I love it.
    Money well spent.

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