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Smart Thermostatic Control 32 for Tankless Water Heaters – Installation Guide
Congratulations on purchasing the most advanced microprocessor-controlled, hot water recirculation pump controller made. This system is designed to run the recirculation pump only when you need it thus saving both water and energy. It is designed and built with pride in the USA to provide years of service and savings.
Unboxing Your Product
1 Smart Thermostatic Control 32 with RJ-45 connector

1 ¾” or 1” NPT Flow Sensor with JST connector

1 Wiring Harness with R-J45 & JST connectors

Items NOT included: The following items are needed for the installation but are not included.
→ PTFE (Teflon) Tape
→ Wire fasteners for securing wiring to the wall
QUICKSTART GUIDE
Before you begin
Perform the following system test.
- Connect the wiring harness to the controller.
- Connect the flow meter to the wiring harness.
- Plug the controller into a wall outlet and ensure that the LED on the side of the controller flashes green 3 times.
- Blow through the flow meter in the direction of the arrow and ensure the controller makes a slight audible click and the red LED turns on for approximately 5 seconds.
If this test fails, inspect the wires connecting to the flow meter to ensure they are not broken or loose. Reconnect the connection ensuring it snaps tightly and re-test.
Quickstart Install
- Install the flow meter at the cold water input to the water heater ensuring the arrow on the flow meter points in the direction of flow.
NOTE: PTFE tape is necessary when connecting to a female NPT connector. PTFE tape is NOT necessary when connecting to a flexible hook-up line as they have a washer that creates the seal. If installing in hard copper piping it is recommend to install the flow meter using a union fitting.
- Connect the flow meter to the wiring harness and plug the wiring harness into the controller.
- Plug the controller into an outlet and plug the pump into the controller.
- Turn a hot water faucet fully on for 1 second and the pump should turn on for at least the initial run time of 5 seconds. If the hot water line is cold the pump should continue to run until hot water reaches the thermostatic cross-over valve causing it to close and the flow to be cut off. When this happens the controller will turn the pump off.
If the pump fails to turn on or fails to stay on past the initial 5 seconds or continues to run after you have hot water at the faucet(s) where the crossover valve(s) is (are) installed, see Troubleshooting.
LED Legend
GREEN LED: will blink 3 times when first plugged in to indicate the unit is functioning correctly.
GREEN LED: solid on when a timer is active and the pump is not running.
GREEN LED: will blink every 10 seconds when no other LED is lit (e.g. no timer active, pump not running)
RED LED: solid on when the pump is running whether due to a timer or due to demand.
BLUE LED: solid on when connected via the smartphone app.
DETAILED INSTRUCTIONS
Please read over the following detailed instructions. If you are not comfortable with any part of them please contact a licensed plumber to perform the installation.
Prior to installation, you must perform the system test at the beginning of the Quickstart Guide.
Installation
- Note the setting of the water heater thermostat and then set it to the lowest temperature setting.
- Shut off the cold water supply to the water heater.
- Open the closest hot water faucet to the water heater to depressurize the hot water line. When water quits flowing, turn off the faucet.
- Disconnect the cold water supply line from the water heater. Be careful not to bend and crease the supply line when manipulating it.
Be prepared with some towels as some water will flow out of the hookup line. As long as all the faucets remain closed you should not get any backflow from the hot water line.
- Connect the flow meter to the cold water input of the water heater using PTFE tape being sure that the arrow on the flow meter is pointing toward the water heater.

- Connect the flexible cold water supply line to the input side of the flow meter. The flexible supply line uses a washer to seal so you don’t need to use PTFE tape on this connection. Hand tighten and turn an additional ¼ to ½ turn. DO NOT OVER TIGHTEN!
- Turn on the cold water supply to the water heater and inspect for leaks.
- Turn the water heater thermostat back to its original temperature setting.
- Connect the flow meter to the wiring harness via the JST connector ensuring the connector snaps together securely.

- Secure the wires to the wall away from the water heater.
- Plug the wiring harness into the Smart Thermostatic Control 32 via the RJ-45 connector ensuring it snaps in securely.

- Plug the recirculation pump into the Smart Thermostatic Control 32 and Plug the Smart Thermostatic Control 32 into an electrical outlet.

- The green LED on the side of the controller will blink 3 times if everything is okay.
- Turn a hot water faucet fully on for 1 second. This will trigger the recirculation pump to turn on and run until the thermostatic crossover valve is up to temperature. The red LED turns on while the pump is running.
- Once the thermostatic crossover valve heats up and closes, the flow will stop and the pump will turn off.
- If the pump fails to turn on when a faucet is fully opened for 1 second, see Troubleshooting Symptom 1.
- If the pump fails to stay on past the initial 5 seconds, see Troubleshooting Symptom 2.
- If the pump continues to run after you have hot water at the faucet(s) where the crossover valve(s) is (are) installed, see Troubleshooting Symptom 3.
If you need further support, please contact:
Leridian Dynamics, Inc. Customer Support or 831-761-8659