Rheem Gladiator Water Heater Service Needed Light On [Solved]

Rheem gladiator water heater service needed light on tells you that there is something wrong with the heater system. Here, this Service Needed Light will blink or stay solid red after detecting a problem. 

The solid red light is an Alert, indicating a disconnected leak sensor. You will find the heater remains operational during Alert. 

Besides, the major blinking error codes in LED include 1, 2, 3, 4, & 5. Each of the flashing red error codes is an alarm code, and the heater will shut down where it needs a special service to resolve.

service light on

Throughout this guide, we have explored every in and out about Service needed light and what to do when you encounter any Rheem gladiator error codes.

Quick Solutions To Rheem Gladiator Water Heater Service Needed Light On

Before moving to the detailing part, let’s have a short glimpse at the below table highlighting all the errors on the service needed light, the meaning with quick solutions: 

Error CodesError IndicationQuick Solutions
Solid red lightDisconnected leak sensor> Check the leak sensor and reconnect it firmly.
> Reset the Wi-Fi module.
> Ensure water is not leaking out of the system. 
1-FlashLower thermistor failure> Check & replace the bad lower thermistor.
2-FlashesLeak detected or shut-off valve error> Dry the water pan using a dryer or a shop vac.
3-FlashesDry fire> Re-fill the water tank.
4-FlashesHeating element wiring or emergency cut out> Reset the tripped ECO.
> Check & replace the heating elements.
5-FlashesPower board error> Call a professional plumber to handle this issue.

What Does Service Needed Light Mean On Rheem Gladiator Water Heater

While operating the Rheem water heater, users often encounter several malfunctions in the system. To specify the problem to the user, there has a built-in Service Needed LED  in the Rheem Gladiator water heater. It is mainly an error indicator of the heater. 

That means, whenever there is something wrong with your heater, the LED starts flickering or blinking as an error indication. 

Anyway, the Service Needed LED will either stay sold red or blink red at a different number of times after detecting the malfunction in the system. 

A Rheem gladiator water heater has basically two types of error codes. That includes:

  • Alert (Solid Red)
  • Alarm (Flashing Red)

When the service needed light remains solid red, it will signify the Alert. Besides, there have five potential Alarm codes for which the Service Needed LED will blink red at a different number of times. 

As the indication for each blinking far differs from the other, the solution will vary depending on the specific number of flashes.

Go on reading to learn what you should do to diminish the error code from the water heater.

Note: You can also read how to fix Rheem’s tankless water heater won’t turn on.

1. Solid Red Light On Service Needed Light [Alert]

If the service needed light on the Rheem Gladiator water heater comes on and stays solid red, it is the error indication of a disconnected leak sensor. 

It also tells you the system has detected a leak or the 24-hour leak detection override gets activated. Apart from this, the LED will remain solid red due to any of the following reasons:  

  • Wifi or communication control error. 
  • Configuration data restore failure.
  • Configuration write limit exceeded.


Whatever the error, follow the below few methods to resolve the error from your Rheem gladiator.

Step 1: Inspect The Leak Sensor

First off, turn off the electric supply at the circuit breaker to your water heater first. Unscrew the cover from the lower cavity of your heater to inspect the leak sensor.

inspect the leak sensor

Now, check the leak sensor to see if it gets detached, or becomes loose. If so, reconnect the leak sensor to the leak rope harness snugly. Replace the bad leak sensor if required. 

Step 2: Reset The Wi-Fi Module

Next, you have to reset the wifi module. The process is quite straightforward. Just, press the wifi Setup button for 5 seconds, and you will hear 3 times beeping from the keypad.

reset the Wi-Fi module

When the wifi indicator light turns blue, set up wifi with your mobile and the heater. 

Step 3: Check For Heater Leakage

If still, the LED is solid red, be sure the water heater senses a leak. Find the source of the water leak and fix it. Then use the 24-Hour Leak Detection Override feature to confirm that there is no leak in the system. 

Then, press the Clear Alarm button for 1 second and release it. This will silence the alarm beep, and the heater will go back into its operation. 

2. Service Needed LED Flashing Red 1 Time [Alarm]

If the service needed light on the Rheem gladiator water heater blinks 1 time followed by a pause, it is the error indication of lower thermistor failure. It is sure that the lower thermistor gets disconnected from its place or stops working. 

rheem gladiator water heater thermistor

Due to a faulty thermistor, the heater starts displaying inaccurate temperature readings, and the service needed light blinks 1 time. 

Generally, the thermistor fails because of mechanical separation between the resistor element and the lead material. Also, due to excessive heat, the thermistor burnt out. 


Here are all the procedures to check and fix the thermistor issue:

Start by turning off the electric supply for the water heater in the circuit breaker. Then, locate and inspect the lower thermistor.

If it is disconnected, you have to connect it properly in its place. Also, replace the bad thermistor if needed.

As there require skills to complete the above task, it will be better to contact a professional plumber to solve the lower thermistor issue.

3. Service Needed LED Flashing Red 2 times [Alarm]

Rheem Gladiator service needed light flickers 2 times if the water heater detection of a leak in the system. The other major reasons that are causing 2 times flickering in the service-needed light include:

  • The rope sensor is in contact with water.
  • Shutoff valve input error.
  • The shutoff valve failed to close.
  • The shutoff valve failed to re-open.


Go through the step-by-step procedures to erase the Rheem leak detection and shut-off valve override error. 

Step 1: As the rope sensor is in contact with the water, inspect the water pan first to look for water.

inspect the water pan for water

If there is no water on the pan, disconnect the sensor. Let the sensor dry completely, and then reinstall it.

Step 2: Now determine whether there is a leak in the water heart. Better to use the 24-hour override feature. If you find any excess water around the water heater, use a dryer or a shop vac to dry out the water.

Step 3: Now in the case of a shut-off valve error, contact a certified plumber to solve this problem. 

4. Service Needed LED Flashing Red 3 times [Alarm]

Due to insufficient water in the heater tank, the service needed LED blinks 3 times. That means there is no water in the tank. Only refilling the water tank can erase this error blinking from the water heater.


Follow the below simple steps to deal with 3-flashes in the Service Needed LED of your water heater:

  • First off, turn on the water supply valve to refill the tank.
  • Make sure that the drain valve and the pressure relief valve are in close position while re-filling the tank.
  • When the tank becomes full, close the water supply valve & the service needed flickering 3 times should be resolved.

5. Service Needed LED Blinking Red 4 times [Alarm]

When the Rheem Gladiator water heater service needed a light flashing red 4 times, there are a few concerning factors that need your attention. For instance:

  • Disconnection of upper or lower heating element wiring. 
  • Tripped ECO.
  • Failure of the upper or lower heating element.
  • The wiring to the ECO is disconnected.


If the error is persisting for a tripped ECO, you have to reset it. Then, inspect the wires going to the heater elements. In case any of the wires are disconnected, reconnect the wires. 

But in the case of a faulty heater element, only replacing the bad element can resolve the problem. You can test the heating element electrically using a multimeter and then replace it if you don’t find any continuity there.

test the rheem gladiator heating element

How To Replace Heating Element In Rheem Gladiator Water Heater

Read through the below step-by-step processes to get an idea about how you will replace the faulty heating element.

replace heating element in rheem Gladiator water heater

Step 1: First, turn off the circuit breaker of the water heater. Remove all the attached screws from the cavity cover. 

Step 2: Remove the insulation to access the element of the cavity compartment. Then detach the plastic cover and the heating element will be exposed. 

Step 3: Unscrew the screws securing the wires to the heating element and remove the wires. Take a 1.5” element wrench and disconnect the heating element.

Step 4: Install the new heating element back in place. Ensure a tightened placement of the element. Then screw the wires tightly.

Step 5: Reinstall the plastic cover and the cavity insulation. Secure the cavity cover by securing the screws. Finally, turn on the breaker. 

5. Service Needed LED Flashing Red 5 times [Alarm]

5 blinks on the service needed light of the Rheem gladiator water heater to occur due to the following reasons: 

  • Upper or lower element relay stuck on.
  • Conversions stuck error.
  • Upper or lower temperature conversion error.
  • Conversion drift error.
  • Temperature protection error.
  • Failure or disconnection of the upper thermistor.


To deal with each of the issues that persist as an indication of 5 blinks on the service needed light, you will require professional skill. 

So, it will be better to contact a certified plumber to resolve the issue precisely.


Why is my Rheem water heater not getting warm?

If the water in the heater is not getting hot, be sure the problem persists from the electrical source. Either the fuse is blown, or the circuit breaker gets tripped. Sometimes, faulty heater elements cause this.

How do I flush sediment out of a water heater?

To flush the sediment from the water heater, you will need a hose and connect it to the drainage valve. Now drain and flush the water from the heater into a bucket. Do it until the water comes clear of any sediment.

Why is my Rheem gladiator water heater beeping?

The Rheem gladiator water heater starts beeping indicating that there is a water leak in the system. Detect the presence of the leak if the floor near the water heater feels moist. In most cases, the heater beeps for the heater overheating or blocked air intake. 

Wrapping Thoughts!

Well! There’s all we’ve it. Hope that all confusion on “Rheem water heater service needed light on” should go away now. Throughout this article, we have walked you through each of the aspects relating to this service-needed feature of the Rheem Gladiator water heater. 

Expectantly, all have become informative enough for you, and now you will resolve the errors by yourself. But still, if you have any questions, do let us know through comments. We are always here for you.

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.

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