Rheem Pool Heater Sensor Failure [5 Easy Solutions]

Most Rheem heater users have a common query about Rheem pool heater sensor failure. The problem indicates malfunctioning of the sensors, and that may persist from any of the heater sensors. Because of temperature sensor failure, users get Rheem pool heater sensor failure code SNS. 

rheem pool heater sensor failure

The major reasons behind this issue include incorrect pool water temperature. In some cases, the dirty sensor fails to operate accurately.

Wrong placement of the sensor, defective wirings, or sometimes the complete sensor control board is the culprit. Go through our comprehensive discussion to get in-depth details.

Rheem Pool Heater Sensor Failure [5 Easy Solutions]

Follow the below troubleshooting steps to get a complete solution for the sensor failure problem of the Rheem Pool heater.

Note: You can also read how to fix Rheem pool heater high limit 2 fault problem.

1. Incorrect Pool Water Temperature

If the temperature sensor has failed to continue its normal operation, there would be a higher chance of setting incorrect pool water temperature.

There is a particular temperature range on which the pool water temperature should be set. If somehow the temperature goes down and rises higher, there occurs temperature sensor failure on your pool heater. 

Also, the heater will trigger by a sensor failure code “SNS.” Anyway, to fix the sensor failure on your Rheem pool heater, you should first check out the pool temperature and set it into the correct range. Go through the below suggestions:


  • Take a thermometer and check the temperature of the pool heater. Mainly there should have a temperature between 36 and 95 degrees Fahrenheit.
  • If you don’t find the temperature in this range, change it right now.
  • Go to the heater control panel and press “Set.” Wait until there appears “Pol” or “Spa” on the controlled display.
  • Now, press the “Up” arrow if you want to increase the temperature level.
  • On the contrary, if you want to level down the temperature, press the “Down” arrow.
  • Wait for some while after selecting the desired temperature. You will see the current pool temperature on display. Now, your sensor failure problem should be solved.

2. Clogged Water Temperature Sensor

The clogged water temperature sensor is one of the most common reasons behind sensor failure.

Because of blockage on this, it fails to sense the water temperature and also will not be able to communicate other necessary components.

Anyway, while troubleshooting the sensor failure of the pool heater, we must have to concentrate on this fact:


  • Locate the temperature sensor first. You will find the sensor on the filter pump. In some models, it is located between the filter pump and the filter.
  • Anyway, after inspecting the sensor, clean it properly. It will be highly better to clean the heater using a cloth that is dampened with rubbing alcohol. 
  • Then, dry out the sensor properly. Make sure the sensor is quite debris free.
  • Now, reassemble the sensor into its position correctly. Ensure a secured installation of the sensor. 

3. Wrong Installment of the Sensor

In most cases, incorrect positioning of the sensor results in false or misleading readings from it.

Sometimes, there may have a loose or corroded connection with P1. However, this time will have to check out the placement of the sensor and correct it:


  • Turn off your heater first and disconnect it from the power connection.
  • Now, inspect the temperature sensor.
  • Carefully notice if it is conveniently mounted all the way into the JACO fitting or not.
  • If not, securely mount the sensor onto the JACO fitting on the header. Now check out if the problem is resolved or not.

4. Reset The Pool Heater

Sometimes, a hard resetting will prove well in the case of sensor failure on the Rheem pool heater.

After a hard reset, all the bugs of any hardware of the heater will easily be eliminated. Also, it will set the function of the heater to factory default settings. 

How To Reset Rheem Pool Heater?

Follow the below instructions in order to reset the Rheem pool heater. By this, we can expect the sensor failure problem will be solved. Also, you will find the heater sensor back operating again. 

  • First, turn off the heater. Also, turn off the circuit breaker.
  • Leave the heater for a while and then turn back on the circuit breaker.
  • Wait for 5-6 minutes to power back on the heater. After that while, the power light will illuminate, and the heater will come on.

5. Replace the Bad Temperature Sensor

Finally, if all the above troubleshooting steps have been ruled out, be sure the sensor of the pool heater has defective.

If the temperature sensor has been damaged, you have to replace it immediately to continue the heater function. Also, there may have the possibility of only a cracked wiring connection. 

How To Replace Bad Temperature Sensor On Rheem

Now, you have to inspect the temperature sensor and replace it if needed. If you are confused about how you will replace the defective sensor, go through the below procedures:

  • Turn off the heater first. Now, remove the front panel by unscrewing the four screws holding the front bezel.
  • Then, to access the sensor, you will need to remove the side panel. You will find heater pipes there. 
  • After the water pumps off, you will find a sensor holding with white nut.
  • Detach the nut. Also, disconnect the connected wires on the board.
  • Now, remove the bad sensor. Place the new sensor there and reverse the above processes. Ensure a secured installment of the sensor in its place.


Why does my Rheem pool heater keep shutting off?

Overheating the system is the root reason behind the turning-off issue. The major reason for heater overheating is a dirty filter, low gas pressure, and restriction on water flow. All those cause your heater to shut off constantly.

What does a thermal regulator do on a Rheem pool heater?

The main function of the thermal regulator on a pool heater is to regulate the water flow in the pool through the heat exchanger. It assists to maintain the outlet temperature above 120°F. 

Is there any reset button on the Rheem pool heater?

Yes, there is a reset button on the Rheem pool heater. Remove the metal panel and locate the button near the thermostat. You will find the button in the middle of the limit switch, colored red. 

Why is my Rheem pool heater not turning on?

If your pool heater is not turning on, a clogged water filter is a leading cause behind this. A dirty filter restricts the water flow so that the heater fails to turn on. Sometimes, a lack of fluent power supply is the culprit. Make sure, if there are any tripped circuit breakers in the fuse box.

Summing It Up

Fixing the Rheem pool heater sensor failure issue is not so hard if you follow our above guide. Hopefully, now you have a better understanding of this issue, we can expect you will easily fix your heater’s sensor problem.

Still, if you have any queries regarding any of the above discussions, feel free to ask us through comments. We are always ready to help you with a solution.

About William

William is the founder of Fireplacehubs.com. He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

2 thoughts on “Rheem Pool Heater Sensor Failure [5 Easy Solutions]”

  1. My Rheem pool heater will not engage. It says it sparks twice and the error message of PV output fault message shows up on board. Any suggestions?

    • Hi Steve

      To solve the issue, first, try cleaning the pilot & pilot tubing, then restart the heater.

      Hopefully, your problem will be solved.

      But if you face such an error message again after cleaning, take help from a technician to check the issue as you may need to replace the gas control valve.

      Wish you all the best.


Leave a Comment