Smart Recirculation Control 32 Troubleshooting Guide

Table of Contents


LED Legend

GREEN LED: will blink 3 times when first plugged in to indicate the unit is functioning correctly.
GREEN LED: will blink once every second for 30 seconds after first being powered on to indicate the device is in provisioning mode.
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: fast blinking indicates that one or both of the temperature sensors are not connected properly.
RED LED: will blink every 5 seconds when Max Pump Run Time is exceeded.
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.

Symptom 1 Red LED flashes quickly after it is plugged in and never stops.

ISSUE: The Smart Recirculation Control 32 is not able to get temperature information from the temperature sensors.

RESOLUTION: Unplug the Smart Recirculation Control 32 from the wall and disconnect all three connections at the Y connector where the sensors connect to the wiring harness. Inspect the pins in the connector and ensure they are not pushed to one side or the other. If they are, you can straighten them with a small screwdriver or pen knife. 

If they are not visibly bent then, it can help to wiggle the RJ-14 connectors as you insert them to ensure the pins drop into the slot in the connector and make solid contact. 

Plug the wiring harness back into the Smart Recirculation Control 32. Plug the Smart Recirculation Control 32 back into the wall outlet.


Symptom 2 The pump won’t turn on when hot water is drawn from a faucet.

ISSUE 2A: The temperature difference between the two temperature sensors is less than the large value in the “Temperature Range” setting (default 8F°), and therefore the controller will not turn on. 

RESOLUTION 2A: If the temperature difference has been met then there is no reason to run the pump. This is normal behavior as the controller should only run the pump when there is demand, and the loop is not up to temperature.

To cause the controller to turn on, you will need to wait for the temperature at the end of the loop to drop and create a temperature difference of 8F° or decrease the large difference value in the “Temperature Range” setting.

ISSUE 2B: The flow being seen at the controller is too low to activate the pump. 

RESOLUTION 2B: Go into “Live Data,” open the faucet in question, and observe the flow value. If the value is not greater than the “Sensitivity” setting, the controller will not turn on. Adjust the “Sensitivity” value to be less than the observed value in “Live Data.” 

NOTE: If you are seeing very low flow at the faucet it is possible the aerator in the faucet is clogged. Removing it and tapping it to remove any accumulated sediment can restore the flow, but they are inexpensive so replacing it is recommended.


Symptom 3 Pump won’t continue running after the initial pump run time expires.

ISSUE: The controller isn’t sensing a temperature difference greater than the large difference that is set in the Temperature Range setting (default 8F°).

RESOLUTION 3A: Ensure that the temperature sensor is securely connected to the copper piping coming out of the water heater as close to the water heater as reasonable. Typically, this will be after the hookup line. If it is loose, re-secure it in place with electrical tape, cover it with insulation, and test it again. If it still won’t stay on, see RESOLUTION 3B.

RESOLUTION 3B: This is typically a situation where it is taking longer than 10 seconds for the pump to get hot water out to the location of the first temperature sensor and cause the temperature difference to be greater than the large difference that is set in the Temperature Range setting (default 8F°).

To test this, after the pump has run for the initial 10 seconds, turn the hot water on again for 5 or so seconds. If the pump kicks on and starts running, then you need to increase the Initial Pump Run Time under Advanced Settings. The default is 10 seconds.

We recommend increasing this by 5 seconds at a time and testing again when the system is cold.

You can also view the “Live Data” in the app, which displays live temperature values and differences to see what is actually being sensed.


Symptom 4 The pump continues to run even though the piping feels hot.

ISSUE: The controller isn’t sensing the temperature difference dropping below the small difference that is set in the Temperature Range setting (default 5F°).

RESOLUTION 4A: Ensure that the temperature sensor at the end of the recirculation loop is securely connected to smooth copper piping and that it is connected before it T’s into the cold water feed into the water heater.

If it is loose, re-secure it in place with electrical tape, cover it with insulation, and test it again.

If it still won’t turn off, see RESOLUTION 2.

RESOLUTION 4B: Open the smartphone app to view the temperature value and temperature difference displayed in “Live Data.”

If the difference is greater than the small temperature difference in the “Temperature Range” setting (default 5F°), then the pump won’t turn off.

Go into the “Temperature Range” setting and increase the small temperature difference value to be greater than the value observed in “Live Data,” and the pump will turn off.

This typically happens in homes where the hot water line isn’t well insulated, and the water loses temperature as it recirculates throughout the home. Do your best to insulate all hot water pipes that you can reasonably access. It will make the system perform better, and it will save you money on energy bills.

NOTE: We recommend that you set the large temperature difference value to be at least 3F° higher than the small temperature difference value.

Symptom 5 The pump turns on when no hot water is being drawn.

ISSUE: Pressure spikes in the cold-water supply line caused by abrupt turning on or off of the cold water (for instance, when a toilet fills or a sprinkler system turns on or by fluctuations in the feed from the utility company) can cause the Smart Recirculation Control 32 to trigger the hot water recirculation pump to turn on.

RESOLUTION: The sensitivity value of the Smart Recirculation Control 32 is too low and should be adjusted higher. The default value of 20 works well but can be susceptible to these false triggers. It is recommended to increase it by 5 pulses at a time to filter out these anomalies.

Symptom 6 No flow is seen on the “Live Data” screen when a faucet is opened.

ISSUE 6A: A wire connecting the flow meter is broken.

RESOLUTION: Inspect the wiring harness where it connects to the flow meter to ensure none of the three wires appear broken. If they are, contact Leridian Dynamics to get a replacement harness. If it looks good, see ISSUE 6B.

ISSUE 6B: Sediment or scale is blocking the flow meter.

RESOLUTION: To confirm this is the issue, perform the following test.

Remove the sensor from the flow meter that is held in place with 2 small silver screws (don’t worry, it won’t leak water when the sensor is removed).

Start the smartphone app, view the “Live Data” screen, and quickly wave a magnet back and forth over the sensor in the direction indicated in the picture. You should see the flow value change.

The flow meter works by spinning a magnet on a turbine that is read by the sensor. If you see a flow value in the smartphone app, the flow meter is blocked with sediment or scale and needs to be removed and cleaned. This can be difficult to perform properly so even if you don’t see flow on the app, baring an obvious problem with the wiring harness, this is the recommended action to take. Here is a short video of the test being performed.