How To Fix Rheem Water Heater 4 Flashes [Gas & Electric]

The Rheem 4 flashes error code indicates that the high-temperature limit has been tripped in gas water heaters. However, it can be caused by other issues in electric water heaters. So, how to fix Rheem water heater 4 flashes?

From many years of experience, I can tell you that the most common solution is replacing the gas valve. You may also be able to solve it by filling the tank completely with water or replacing the thermal well. However, I’ve also shared a trick to bypass this error code.

On top of that, you’ll also learn how to fix this error code if it comes up in your Rheem electric water heater. So, let’s dive in!

How To Fix Rheem Water Heater 4 Flashes [Gas Water Heaters]

We’ll look at the main reasons behind the Rheem water heater status light blinking four times in this section.

01. Exceeded Water Temperature Limit

A Rheem heater has many safety devices to prevent accidents. One of them is the water temperature limit safety device. It gets tripped whenever the temperature of the water is so high that it’ll cause scalding.

Generally, the water temperature limit gets tripped at 180 degrees Fahrenheit. The gas control thermostat cuts off the gas supply to the water heater when it happens. The four flashes error code from the gas control valve’s status light also comes up. The flashes will be in red color.

How To Fix:

The water temperature limit being exceeded is a serious issue. You should consult a technician if this error code won’t go away. However, I’ve shared a nifty little trick to make this error code disappear. Keep scrolling down to find it and read it.

First, try the tips mentioned in that trick. If that solves the problem, that’s great. Otherwise, you should hire a technician to fix the issue. More often than not, you’d have to replace the gas control thermostat to solve this problem.

02. Tank Is Not Fully Filled

The tank has to be completely filled with water for the heater to work properly. If the tank is not completely filled, the heat from the main burner won’t be distributed as much as it’s supposed to.

So, the water temperature can be too high and the limit switch can get tripped in this situation. That’s how the 4 flashes error code can also come up from this issue. Remember the flash code won’t be red in all types of gas valves. Depending on your gas valve, the flashes can also be blue.

How To Fix:

You’re very lucky is a tank that’s not fully filled is causing the issue. That’s because you couldn’t ask for a more simple fix. Check if the tank is completely filled with water. If it’s not, then maybe someone turned off the cold water supply and forgot to turn it back on.

So, turn on the cold water supply and wait for the tank to be fully filled. Hopefully, the error code will go away after that and you’d get hot water from your heater again.

03. Thermal Well Fault

The thermal well is the part of the gas control valve that connects to the tank of the water heater. Issues with the thermal well can also trigger the four flashes code in Rheem water heaters.

How To Fix:

Try power cycling the heater first and see if that solves the issue. That means you can turn off the heater, wait for a while, and turn it back on. If the code disappeared, it was due to a temporary issue, and the problem is solved.

If the code remains, your next line of action is to reset the gas control thermostat. You can follow these steps to do it:

1. Unplug the water heater from its power outlet and turn off the gas control valve.
2. Wait for a few minutes for the gas to clear out.
3. Connect the heater to its power outlet and turn on the gas control valve. You have to do this next step within 30 seconds:
4. Set the gas control knob to the lowest settings and turn it to the highest settings. Then, go from the highest settings to the lowest settings. Go back and forth like that seven times total. Feel free to use a flathead screwdriver to speed up the process of turning the gas control knob.

That’s how you can reset the gas control valve. Hopefully, resetting the gas control valve will make the code disappear. If it does, you can set the thermostat to your desired temperature and call it a day.

But if the four flashes code still remain, you’ll have to remove the thermal well in your water heater. You should hire a qualified technician if you don’t feel fine doing it yourself.

04. Defective Gas Control Thermostat

One of the most common reasons behind the four flashes error code in Rheem gas water heaters is a bad gas control valve. If the thermostat doesn’t read the temperature properly, it won’t send the signal to cut off the gas supply.

The main burner will continue to heat the water as there’s nothing stopping it. So, the limit switch will get tripped and that’ll trigger the error code.

How To Fix:

It’s simple – you’d have to replace the faulty thermostat. But keep in mind that the gas control thermostat is an expensive component. So, you should test it properly to make sure it’s bad before replacing it.

Check out my Rheem gas control valve guide to learn how you can test it. If it turns out to be bad, you’ll also find detailed instructions on how to replace it.

How To Override The Rheem 4 Flashes Error Code?

The gas valve will get into lockout mode when there’s an error code with the heater. The ideal solutions to this problem have been explained above. But you may not always have the budget and resources to change the gas control valve when it goes bad.

But wait, there’s good news. There’s a neat little trick that you can follow that may override the error code. If it works, you won’t have to replace the gas control thermostat.

If the status light is already off, that’s because the pilot is out too. You’ll have to relight it. As soon as you light the pilot again, the error code will appear again. Follow these steps to relight the pilot and override the error code:

1. Turn off the main gas supply to your water heater and set the gas control knob to the “Off” position. Wait for a few minutes for the gas to clear out from the pilot and the main burner area.
2. Turn on the main gas shut off valve and adjust the gas control knob to the “Pilot” position. Keep pressing the igniter button once every second until the status light starts to blink. You can confirm that the pilot is lit at this stage by looking through the viewport.
3. Turn the gas control knob to the “Very Hot” position immediately and wait for ten seconds. Then, turn the knob to the “Hot” position and wait for 10 seconds. Similarly, turn the knob to the “Pilot” position and wait for 10 seconds.
4. You can change the position of the gas control knob to your desired temperature settings. The main burner will come on if the error code was successfully overridden.

Now, there are a few things you should keep in mind if you want to use this trick. Ideally, you should set the temperature “Low” and “Hot” points in the gas control knob.

Setting the knob over the “Hot” position tends to trigger the error code again. How soon it’ll come back varies on the heater. It could be an hour, a few weeks, or even a year. 

With that said, a round of applause for you if that removes the error code. Hopefully, you’ll be able to use your heater for a while in this condition. If the code comes back again, you can always retry this trick.

But keep in mind that this trick will only work for so long. You should use it as a temporary solution if you’re not ready to change the gas control valve. For a long-term solution, it’s a good idea to replace the gas valve.

How To Fix Rheem Water Heater 4 Flashes [Electric Water Heaters]

There are some Rheem electric heaters that are equipped with an electronic control system. You’ll see error codes on such heaters when there are some specific issues with the water heater.

If the heater flashes four times, it usually points to issues with the element wiring or the emergency cut-out. Here are the main reasons behind this error code along with the fixes:

i) Wiring Issues

If you’re facing this issue in a new water heater, there’s a good chance that it’s due to wiring issues. It’s possible that the person who did the installation did a poor job. There are many types of wiring mistakes that can trigger this four flashes error code.

For starters, switching the upper or lower heating elements wire with one another will cause this problem. If any of the heating elements are disconnected from their respective wires, that’ll also throw this four flashes code in Rheem electric heaters.

How To Fix:

First, make sure that the upper and lower heating element wires aren’t switched. If they had been switched, place them back in the right order.

Secondly, inspect the connection between the heating elements and the wires. If any of them are loose, tighten them. Hopefully, that’ll fix the issue.

ii) Tripped ECO

The Emergency Cut Off or ECO is a safety device in Rheem electric heaters. It gets tripped when the water temperature inside the tank becomes too hot to handle.

The water is usually at such a high temperature for it to trip that it can cause instantaneous scalding. The heater won’t be operational after the ECO trips. It can also trigger the four flashes code.

How To Fix:

You’ll have to reset the thermostat to continue using the heater if the ECO has tripped. Hopefully, that’ll also erase the error code and you’ll be able to use your heater without further problems. Follow these steps to do it:

• Turn off the circuit breaker attached to the heater to disconnect the power supply to it.
• Remove the screws holding the upper thermostat cover in place.
• Take out the cover and the insulation to have access to the reset button.
• Press the reset button and you should hear a clicking sound when the heater has been reset.
• Attach the insulation, the cover, tighten the screws, and restore the power supply to the water heater.

So, that’s how you can reset the heater. However, the bigger question here is what caused the ECO to trip in the first place. The water isn’t supposed to get so hot to trip the ECO. Check out my Rheem reset button guide to learn more about why it happens and how you can fix that issue.

iii) Heating Element Failure

The heating element is arguably the most important component in the water heater. It gets powered by electricity and uses that energy to heat the water. There are two heating elements in most Rheem heaters.

If any of the heating elements fail to do its job, the hot water won’t be properly heated. If any of them are shorted, the hot water can be overheated. So, failure of any one of the heating elements can lead to many hot water issues. It can also trigger the dreaded 4 flashes error code.

You should check if the heating element in your heater is actually bad to be certain about it. All you need to do is a multimeter. You can follow these steps to test the heating element:

1. Turn off the power to the water heater and remove the screws holding the thermostat covers in place.
2. Pull out the thermostat covers and remove both the insulation and the plastic covers.
3. Set the multimeter to the lowest resistance settings and connect its probes to the heating element screws.

Now, it’s time for the big reveal. If the resistance was within the range of 10 to 16 Ohms, that means the heating element is absolutely fine. Otherwise, there are issues with it. Make sure you check both the upper heating element and the lower heating element as both of them are potential culprits here.

How To Fix:

If the test reveals that you have a bad heating element, you’ll have to replace it. Make sure you get the right replacement heating element for your water heater. Once you do that, here’s how you can complete the replacement procedure:

1. Turn off the power to the heater. Remove the access cover, the insulation, and the plastic cover.
2. Close the cold water supply valve and open a hot water faucet to relieve the system pressure.
3. Drain the tank all the way if you’re replacing the lower heating element. You can just drain half the tank if you want to remove the upper heating element.
4. Use an element wrench to loosen the heating element and pull it out. Put the new heating element in place of the old one.
5. Tighten the new heating element and reverse engineer the above steps to put everything back together and complete the installation.

That’s how easy it is to replace the heating element on your own. However, not everyone will feel comfortable doing it. If that’s you, hire a qualified technician to do the job. The error code should go away after that and hopefully, you’ll get plenty of hot water from here on.

FAQs:

Conclusion

The status light blinking four times in Honeywell gas valves of Rheem water heaters is a common issue. But now you know how to fix Rheem water heater 4 flashes with detailed instructions.

You can fix this problem not just in gas water heaters but in electric water heaters as well. Hopefully, you won’t have to replace the gas control valve to solve this issue. Check out my Rheem 8 1 flashes error code guide if that comes up in your water heater.