Rheem Water Heater Blinking Light Codes

11 Common Rheem Water Heater Blinking Light Codes

This is a complete guide on Rheem Water Heater Blinking Light Codes, where I will describe:

  • What does blinking light mean on Rheem Water Heater?
  • What are the red blinking light codes on Rheem Water Heater?
  • What are the status light blinking blue codes on Rheem Water Heater?
  • What are the Rheem Gladiator Water Heater Error Codes?

What Does Blinking Light On Rheem Water Heater Mean?

Blinking light on Rheem water heater stands for a specific problem your water heater is going through. What the issue will be with the unit depends on how many times the status light flashes consecutively every three seconds. 

Besides, the color of the blinking status light represents different water heater problems. Generally, Rheem water heaters flicker two light codes- red and blue. For example, blinking the status light 7 times every 3 seconds will indicate different problems determined by the color codes. 

If the red light flashes 7 times, understand it’s the problem with the gas control valve. On the other, blinking blue light indicates the flammable vapor sensor goes into lockout mode.  

What Are The Red Blinking Light Codes On the Rheem Water Heater?

If the status light blinks red on the Rheem Residential Gas Water Heater, understand there is a system problem. What problem it indicates will depend on the number of flashes on the status light.

For example, if the Rheem Water Heater LED indicator light flashes two (2) times, I bet the thermopile voltage is low. On the other hand, the status light blinking red seven (7) times indicates that the gas control valve is at fault. 

What Causes The Status Light to Blink Red On Rheem Water Heater

01. Rheem Water Heater Flashing Red Light 1 Times

Blinking red light 1 time every three seconds represents your water heater is functioning in its tip-top condition. It indicates the temperature knob is in the pilot position and it stays lit. In short, 1 flashing red light stands for normal water heater operation. 

How To Fix: 

You don’t need to do anything significant as the unit is in good condition. What you need to do is- just fine-tune the temperature knob and set it to your desired temperature setting. 

02. Rheem Water Heater Flashing Red Light 2 Times

Two flashes consecutively every 3 seconds mean there is a low voltage on the thermopile of your water heater. 

Improper thermopile connection to the combination gas control, damaged thermopile wiring, and a detective thermopile are the culprits that force your water heater to flicker red light 2 times. 

How To Fix: 

The main culprit that is responsible for low thermopile voltage is- the thermopile connector is improperly connected to the combination gas control valve. So, inspect the connection and ensure you properly attached that connector to the combination gas control. 

Next, damaged the wiring leading from the thermopile to the combination gas control. If it gets worn out, it will send no electrical power to the gas control.  

Finally, it’s time to replace the thermopile if it’s at fault. However, I recommend you test the thermopile electrically before changing it. You should use a multimeter to take a voltage reading. The voltage of a functional thermopile should be between 650 to 850 millivolts. If you don’t know how to test the thermopile on the water heater, check out the following tutorial: 

Anything below 450 millivolts indicates the thermopile is the defect and you need to change it. In this case, this video will come in handy to replace the thermopile on your Rheem water heater: 

03. Rheem Water Heater Blinking Red Light 4 Times

If your Rheem water heater flickers 4 times every three seconds, I bet the water temperature limit switch or the reset button gets tripped. The reset button on the Rheem water heater will keep tripping due to the following reasons: 

  • A faulty thermostat
  • The heating element goes bad
  • Loose wiring 
  • The high limit switch or the reset button is at fault

How To Fix: 

Begin with inspecting the electrical of your Rheem water heater. Due to bad installation, the wiring will get damaged or loose. I recommend you call for help from a certified electrician if you are not electronically inclined. 

Next, I prefer you to check the heating elements to see whether it’s in good condition or not. Before heading over to replace it, it’s recommendable to test the heating element electronically. 

Regarding this, you should remove the cover panel and the insulation to access the heating element. Then, snap out the plastic cover from over the thermostat. 

Next, use the multimeter and use the leads to touch the probes to the screws on the heating element. You should get the reading between 10 to 18 Ohms. 

Otherwise, you should replace the heating element. You can find the following video helpful in this case: 

Safety Tips: You must go to your main fuse box or breaker box. And you need to shut off the power to the water heater completely before testing the heating element. 

And lastly, it’s time to check both the thermostat and the reset button. One thing I want to inform you is that- if any of these two elements go bad, you need to change both of them. It’s because the reset button is part of the thermostat. In this case, this tutorial from Rheem will help a lot if you want to change the thermostat yourself. 

04. Rheem Water Heater Blinking Red Light 5 Times

Five blinks every 3 seconds! I am pretty sure it’s the problem with the water temperature sensor. Over time, it will get damaged or covered with sediment. Consequently, it will stop working the way it should function. 

How To Fix: 

I suggest you leave this task for a certified plumber as it takes a lot of elbow grease and experience as well.

05. Rheem Water Heater Blinking Red Light 7 Times

The red light flashes 7 times every three seconds! Then, the culprit behind this issue is the gas control valve. If it’s at fault, it will cause the status light to blink red. And you know it’s the gas control valve that regulates the gas flow. 

A defective combination gas control failure means the unit will not get the fuel it needs to heat the water. It means you will no longer get any hot water on the chilly day of winter unless you replace the gas control valve. 


Once you observe the status light blink 7 times consecutively, you should replace the gas control valve. I suggest you watch the following tutorial in this regard: 

06. Rheem Water Heater Flashing Red Light 8 Times

Status light flickers red light 8 times every three seconds! Then, I can smell the false pilot light signal. If the pilot valve is stuck in an open position, your Rheem throws this pilot issue by blinking the red light. 


The pilot valve will be stuck in the open position due to defective gas control. Changing the gas control may bring luck in this case. However, I highly recommend you hire a professional to do this task for you. 

07. Rheem Water Heater Red Light Flashing 9 Times

A few weeks ago, I encountered this problem. Once I observed the red light flashing 9 times, I opened the bible (manual) of the Rheem water heater. Alas! The troubleshooting manual only breaks down the status light codes to 8 flashes. 

Indeed, it doesn’t mention what it means if the red light flashes 9 times every three seconds. 

After hours of researching, I found the 9 consecutive flashes mean the chamber sensor is at fault. 

How To Fix: 

Again, my suggestion is to call a professional to deal with this issue if the red light flashes 9 times. Of course, a faulty chamber sensor can cause this problem. However, a gas control valve can also be another culprit behind this. 

So, it’s advisable to call a certified plumber to do it for you. However, you can replace the chamber sensor if you feel comfortable DIYing this task. In this case, this tutorial will come in handy: 

What Are The Status Light Blinking Blue Codes On the Rheem Power Vent Water Heater?

On the power vent model, the status light blinking blue indicates a system problem- quite the opposite on other models. The number of blue flashes will indicate a specific water heater problem. 

For example, the status light flashing blue three (3) times means an open draft pressure switch. On the other hand, if the status light blinks seven (7) times, I bet that the flammable vapor sensor is in lockout mode. 

What Does Cause The Status Light to Blink Blue On Rheem Water Heater

08. Rheem Water Heater Flashing Blue Light 3 Times

Flickering blue light 3 times on the Rheem water heater indicates there is an issue with the pressure switch. 

A clogged hose that goes from the draft motor to the pressure switch is the main culprit behind this issue. Besides, high voltage can also be the problem that blows out the pressure switch and it causes the water heater to blink blue. 

If the pressure switch is at fault, the water heater will not run properly as the switch shouldn’t remain in a close position. 

How To Fix: 

You should replace the faulty pressure switch for proper furnace operation. Now, the question that will arise in your mind is- how do I know whether the pressure switch is at fault or not? 

Well, you should test the switch electrically. Just grab an Ohm meter and take the voltage measurement by placing the leads on both terminals of the switch. 

A healthy pressure switch should give 0 to 0.1 reading. If the reading climbs above this range, you are right to go to change the switch. Follow the below steps to make the replacement: 

  • Ensure you turn the power off to your water heater completely.
  • Remove the upper access panel from the unit by snapping it.
  • Pull out the small vacuum tube from the pressure switch. 
  • Disconnect the two-wire connectors from the pressure switch. 
  • Now, remove screws using a flat head screwdriver that holds that pressure switch in its place. 
  • Take the old pressure switch out and install a new pressure switch. 
  • Finally, end the replacement workflow by putting everything back into its place. 

09. Rheem Water Heater Flashing Blue Light 6 Times

If the water heater flashes blue light 6 times every three seconds, I am pretty sure there is a leak in your water heater. 

A corroded or defective T&P valve is the main caveat responsible for leaking water out of the unit. Besides, excessive water pressure and damaged internal tanks are other culprits that will leak water. 

Note: There are a lot of reasons behind a leaky water heater and I only mentioned a few of them. I think it needs another guide to break down why the Rheem water heater is leaking. And the guide will come Live on Sunday. So, keep your eyes on our website for the update. 

How To Fix: 

If the water pours out of the T & P valve, you need to replace it. A simple test will tell you whether the valve gets corroded or not. Just open the T & P valve with your hand and the pressure will escape. If it doesn’t pass this test, you need to change it. Below, we will break down how to replace a water heater T&P valve. 

To make this replacement, you need the following pieces of equipment: 

  • A new T&P valve
  • PVC drain line
  • A pipe wrench or an adjustable wrench 
  • An extension or Cheater bar
  • Flat blade screwdriver 
  • Teflon tape or pipe sealer
  • A garden hose
  • Rags or towel

Attach a length of garden hose to the bottom of your water heater. And run the other end of the hose to the nearest floor drain or a safe spot outside of the home. 

Close the shut-off valve at the cold water inlet line or main water supply. 

Next, open a hot water faucet somewhere in the house that will relieve the system pressure inside the tank. 

Now, open the drain valve and allow approximately 1 gallon of water to drain for a top-mounted T&P valve or ten gallons for a side-mounted T&P valve. 

Afterward, detach the run-off tube connected to the T&P valve. 

Remove the old T&P valve with a wrench. You may need to use a cheater bar or a short length of metal pipe for extra leverage. 

Finally, you are ready to install the new T&P valve. Use the Teflon tape to seal the thread.

Make sure the new T&P valve is in the closed position and install it. Reconnect the new PVC drain line to the T&P valve. Now, open a hot water faucet somewhere in the home and open the shut-off valve at the cold water inlet line or main water supply. 

You will hear the heater tank start to fill. Then, lift the lever on the T&P valve. When you have a steady stream of water from the T&P drain line, close the valve. Also, turn the faucet off when you have a steady stream of water from the hot water faucet. 

Congrats! You made the replacement. 

10. Rheem Water Heater Flashing Blue Light 7 Times

Your Rheem water heater will flicker blue light 7 times every three seconds if the flammable vapor sensor goes into the lockout mode. Resetting the sensor will unlock the lockout mode. 

How To Fix: 

I suggest you watch the following tutorial to learn how to reset the flammable vapor sensor.

Alternatively, you can take help from a certified plumber to do this for you. 

11. Rheem Water Heater Flashing Blue Light 8 Times

It indicates the flammable vapor sensor goes out of specification if the blue light blinks 8 times every 3 seconds. It is because of either a bad thermostat well or a damaged sensor. 

How To Fix: 

I highly recommend you call a professional plumber to deal with this problem. 

What Are The Rheem Gladiator Water Heater Error Codes?

Rheem Gladiator Water Heater has a digital control. The service needed light will blink red or remain solid red depending on the type of water heater problem. 

Service Needed LED remains solid red if the unit detects one of these problems: 

  • The Leak Sensor Gets Disconnected
  • Wi-fi or control communication error
  • Leak detected

Read this article on Rheem Gladiator Solid Red Light to discover the solutions. 

The following table will describe why the Service Needed LED blinks red and the reasons for it. 

Service Needed LED Blinks RedReasons
1 TimesDefective Lower Thermistor
2 TimesShut-off valve failure
3 TimesTank not filled with water
4 TimesDisconnected upper or lower element wiring, Tripped ECO, Defective element
5 TimesStuck relay, Conversion Error, On-board temperature protection error

To discover more: Rheem Gladiator Water Heater Service Needed Light


Blinking light codes will indicate something is going wrong or the water heater functions intermittently. Each blinking light stands for a specific problem. So, if you know the meaning of the status codes, you can easily detect the problem and solve it. 

And this guide on the Rheem water heater blinking light codes is exactly what you are looking for. I highly recommend you bookmark this guide so that you can use it when you face the flashing light code issue in the future. 

The best part is- we also broke down the troubleshooting steps you need to follow to avoid the specific blinking light code issue. Indeed, it’s worth bookmarking this guide. 

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