Leridian Dynamics

Leridian Dynamics, Inc. is an electronics design and manufacturing company located in Watsonville, California, USA. Leridian Dynamics is the manufacturer and distributor of the Smart Recirculation Control family of hot water circulating pump controllers for tank and tankless water heaters using smartphone technology.

Founded: 2015 by David Lehrian. 

Leridian Dynamics, Inc. Logo

Our Mission

Leridian Dynamics is dedicated to providing cost effective environmentally beneficial solutions that make conserving resources convenient. 

We have designed and built a variety of microprocessor-based environmental controls including the Smart Recirculation Control which is used to turn any hot water recirculation pump into an energy-efficient on-demand recirculation pump. 

Addressing the Water Crisis

The water crisis is growing every year. Our on-demand hot water delivery system saves thousands of gallons of water per year by delivering hot water fast, without wasting water while waiting for hot water to arrive. 

Reducing Utility Costs and Energy Use

As homeowners quickly discover a recirculation system that runs 24/7 wastes a tremendous amount of energy not only from running the pump but from heating loss through the piping. 

See our Smart Recirculation Control Water and Energy Savings Calculation White Paper. 

Affordable Solutions

We’ve kept our prices as low as possible to allow people of all income levels to have access to affordable solutions to water conservation, the convenience of on-demand hot water, and help control high utility costs. 

To expand the benefits, especially to small business owners, our Smart Recirculation Control units can be installed in average-sized facilities as well as provide solutions to larger businesses with our Digital Aquastat Control that helps businesses save money on utilities, plumbing system repairs, and to help them conserve water.


A timer-based solution is great for people who maintain a consistent schedule, but having a pump that also turns on when someone draws water without having to run wires to every sink, tub, and appliance in the house is the real benefit. 

The Smart Recirculation Control is easy to install and retrofit any domestic hot water recirculation pump and is 100% contained within the utility closet.  

The total install time is approximately 60 minutes.

Customer Feedback

Brandon G. 2021-04-04


Works great. My circ pump is running only when needed instead of 16 hours a day on a standard timer. All I have been doing is heating up the concrete slab. Makes no sense why hot water lines in concrete are not sleeved or insulated. 

This device is going to save me a ton of money in electricity usage. My hot water heater is cycling very little as compared to running non-stop before. It was costing me over $200/month to heat water before. I’m anxious to see my new electric bill after installing this smart device.

Philip G. 2021-09-23


Their customer service is outstanding. They actually called me a couple of times to make sure I knew what I was doing, which I did not.

Unfortunately, the internal wiring of my tankless was incompatible with the product which works as promised. I almost considered buying a new water heater just so I could use the device.

My tankless hot water heater is a Rinnai RU80e (KB2530WD) with a Grundfos GT15 Kit and Rinnai Circ-Logic, purchased in 2014. Hopefully it is a rare model that is incompatible with the Smart recirculating system.

It is a great product with OUTSTANDING customer service.

Kaelin S. 2022-01-30


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.