Rheem Water Heater’s Blue Light Flashing – Fixed

Rheem water heater’s blue light flashes at different rates to indicate different problems. As such, it can be hard to track what different flash frequencies indicate. 

When your Rheem water heater’s blue light flashes, it either indicates that the heater is functioning normally, that the pressure switch is faulty, or that there is a leakage from the heater. Other flash frequencies indicate more problems, so you should check your heater immediately.

Rheem water heater’s blue light flashing
Source: Rheem water heater flashing code blue 6,3 or 3,6. Water not heating

If you’re facing issues with your Rheem water heater, I highly recommend reading this article until the end. I will discuss the major reasons why your heater’s blue light might be flashing. 

What Does It Mean When My Rheem Water Heater’s Blue Light Is Flashing?

In this section, I will discuss some of the primary reasons why your Rheem water heater’s blue light might be blinking/ flashing. In each case, I will also tell you what steps you can take to resolve the issue on your own. 

However, If you’re not confident you can fix the issue on your own, and if you’re afraid you’ll damage the heater while attempting these repairs (which, of course, happens), you should ignore these DIY fixes and either call an expert plumber or Rheem’s customer support team itself. 

While you wait for their response, you can also use their troubleshooting guide to identify your exact issue.

1. Single Blue Light Flashes Mean Your Rheem Water Heater Is Functioning Normally

Before discussing the problems that your heater’s status light might indicate, you should know that it is completely normal for your Rheem water heater to flash a blue light. 

Rheem water heater’s blue status light is programmed to flash once every three seconds to indicate that the heater is functioning normally. 

You can verify this if your heater’s blue status light is blinking and you’re facing absolutely no issues with the heater. 

However, if the blue light is flashing and you are facing issues with your Rheem water heater, then you need to pay close attention to the intervals between each blink. 

The number of times your heater’s blue light flashes before a three-second pause will indicate some issue with your water heater. You can find out the problem by opening the manual and checking the problems listed next to the corresponding number of blue flashes. 

Rheem Water Heater

2. Three Blue Light Flashes Indicate An Issue With The Pressure Switch

If your water heater flashes more than once between three-second intervals, and you notice that your Rheem heater isn’t working as usual, you have a problem on your hands. 

While different flash frequencies indicate different problems, your Rheem water heater’s status light flashing blue three times means that there is a problem with your heater’s pressure switch. 

Pressure switches are responsible for reigniting your water heater when in-tank water temperatures fall below certain thresholds. 

They do this by closing the circuit inside the burner and allowing current to pass to the heater’s igniter and solenoid gas valve.

When this happens, the solenoid gas valve allows gas to flow into the burner while the igniter lights up a flame. 

Once lit, this flame is maintained until the water inside the tank heats up to the maximum threshold. 

If you want to learn more about how pressure switches help reignite burners, Here’s a YouTube video that explains it—it’s brief and gives you a great visual mapping of the process:

How To Fix

If you find that your heater’s pressure switch is faulty, you’ll need to replace it. 

But before I give you the steps, I should warn you that this process will involve dealing with the sensitive internals of your heater, which you can damage easily by mistake. So, I highly recommend hiring a plumber to do the job.

If you still want to know what to do, here are the steps:

  1. Start by switching off your water heater completely.
  2. Then, remove the plate above your heater’s pressure switch (it should be right next to the fan motor).
  3. Now, remove the air tubes connected to the pressure switch. 
  4. Get a new pressure switch (same model and size).
  5. Unscrew the old pressure switch and screw in the new one.
  6. Connect air tubes to the new pressure switch. 
  7. Make sure all wires are connected properly. 
  8. Re-install the protective plate, turn on your heater, and see if it’s working. 

Check out this 14-minute YouTube video I found that shows you how to diagnose and replace your heater’s pressure switch in detail—it’s so much better than reading manuals.

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3. Six Blue Light Flashes Indicate That There Is a Water Leak

Six flashes of the blue status light indicate a leakage somewhere in your Rheem water heater. 

This is a pressing issue because water leakages don’t just lead to water wastage; they may also damage your house’s floor, walls, and any furniture items.

Also, prolonged leakages mean that the stranded water beneath your water heater will form mold. And if you don’t do anything about it soon, it could cause you and other household members to fall sick.

Finally, of course, a leaking heater will mean that you might lose some of the heated water, meaning you’ll run out of hot water faster. Although, usually, leakages aren’t this severe.

How To Fix

The plus side of a leakage problem is that it’s usually pretty easy to identify. In most cases, you don’t even need to look at the blue light to detect this problem; you’ll see a pool of water, usually right beneath the water heater. 

Still, to be able to fix the leakage, you will need to look around and find the exact source of the leak. Most commonly, you’ll find the leakage source(s) in one of these places:

  • A damaged water tank
  • Loose pipes
  • Drain valve
  • Damaged temperature and pressure relief valve (T&P Valve)

Here are the steps you should follow to solve this leakage problem:

  1. Start by zeroing in on the source or sources of the leakage.
  2. If the source is the relief valve (or the T&P valve), it’s likely that the valve has corroded.
  3. Get a new T&P valve and replace the older one. You can do this yourself or by hiring a professional plumber.
  4. Plastic drain valves can crack over time and cause leakages too. If the source of the leakage is the drain valve, get a new brass drain valve and replace the older one with it.
  5. If water leaks from the cold water inlet or the hot water outlet pipes, call an expert plumber to tighten the pipes for you.
  6. Finally, if none of these outer connections seem to be the problem, the leakage is probably sourced from the inner tank.
  7. Unfortunately, inner tank leakages usually mean that the tank has corroded, meaning the only way to stop leakages would be to get a new tank. Call an expert plumber for the job.

If you’d like to see all of these steps visually, here’s a great YouTube video I found that I think will give you a good visual walk-through of all of these steps:

Rheem Water Heater Blue Light Blink Codes

In the sections above, I’ve only discussed the most common problems that the Rheem water heater’s flashing blue light indicates. 

However, the flashing blue status light signals other problems as well. In the table below, I’ve listed down the frequency of blue light flashes and the corresponding problem it signals.

Frequency of blue flashesMeaning
0Either the gas control is off, the pilot isn’t lit, or there is insufficient power.
1Normal function.
2Low thermopile voltage.
3Faulty pressure switch.
4Upper water temperature threshold is reached.
5Faulty temperature sensor. 
6Water leak.
7Faulty gas valve.
8Pilot flame signal isn’t working.


To sum things up, it is completely normal for your Rheem water heater’s blue status light to flash, provided that it flashes once every three seconds. 

Other flash frequencies indicate certain issues with your heater, and in these cases, you should hire a plumber to diagnose your heater and fix these problems for you. 
Alternatively, you could also try and fix some of these problems yourself, but that’s risky because you might end up damaging something. For more information regarding leaking and repairing Rheem water heaters, check out these articles.