The major reason behind Rheem tankless water heater keeps turning off include:
- Loose or damaged wiring connection
- Low water flow
- Using too many hot water fixtures at a time
Before considering anything else, shut off the extra hot water fixtures that keep tripping the breaker. Plus ensure a minimum water flow to the unit. In case you suspect bad wiring or a short circuit is the cause of your problem, then you need to consult a professional electrician.
If still, the problem persists, improper gas & air supply, dirty combustion chamber, and plugged-up heat exchangers are the root causes behind your Rheem gas tankless water heater keeps turning off.
Besides, consider you have a bad circuit breaker or worn-out heating elements in case of Rheem electric tankless water heater malfunctions.
Let’s dig deeper to learn the solving process of each reason mentioned above.
Table of Contents
How You Fix Instantly:
From my own experience, I’ve discovered that a few particular issues lead to the system turning off randomly. Before getting details, let me make your reading shorter through this quick table highlighting all the reasons for this issue with the recommended solutions:
| Probable Reasons | Recommended Fix |
| Loose or damaged wiring connection | #Fix or replace the bad wiring |
| System overload | #Minimize the hot water demands by turning off extra hot water fixtures |
| Low water flow | #Inspect the water flow sensor and water filter for any obstructions and clean them. #Turn the water shut-off valve all the way. |
| Faulty gas supply (Gas Model) | #Inspect the LP tank for fuel amount and refill it if needed. #Check for gas pressure in the unit and adjust it. #Remove the obstructions from the gas supply line |
| Air blockage (Gas Model) | #Clean out the air filter screen and venting system. #Make sure the vents are not too short. |
| Dirty burners or igniter (Gas Model) | #Clean out the burner, igniter, and flame rods. |
| Plugged-up heat exchanger (Gas Model) | #Flush out your tankless water heater |
| Bad circuit breaker (Electric Model) | #Replace the bad breaker |
| Worn-out heating elements (Electric Model) | #Replace the non-functioning heating elements. |
Common Reasons For Rheem Tankless Water Heater Keeps Shutting Off [Fixed]
Here are the most common reasons for this issue in the case of both models (gas or Electric) with the effective fixes:
01. Loose Water Heater Connections
If your Rheem tankless water heater keeps turning off whether it is a gas model or an electric model, a loose connection in the water heater is the first factor that you need to concentrate on.
If there is any defection in the internal wiring or have a short circuit, you will encounter such an issue. This can happen for a number of reasons like improper handling of the heater or damages occurring during installation
Whatever the cause is, faulty internal wiring is certainly a serious problem that can even pose a fire hazard as well. Thus, quick troubleshooting is a must
How To Fix:
The safest thing is to turn the power off and let it off until you are fixing the issue. But the short circuit or faulty wiring should be accessible and fixable by a professional especially when you’re technically inclined.
Also, remove the access panel and figure out the loose connection to the water heater parts, and tighten them. If you find any signs of wear or damage on any elements, you need to inspect and replace them if required.
02. Running Too Much Hot Water Fixtures At Once
If your water heater is shutting off, the best chances are your hot water demand is exceeding the limit that the unit is capable of producing. The term is known as system overload.
Basically, every water heater has a minimum flow rate that defines the capacity of what the heater will produce at a time. Now if you are exceeding the limit by using too many hot water fixtures at a time, it will cross its minimum flow rate.
And when this happens, the unit will shut off or cycle in and off to protect the internal electronics. As a solution, you need to reduce the hot water demands to make the power to your tankless water heater stable.
Here are a few tips you can follow:
How To Fix:
First off, turn off the extra hot water fixtures that you are running simultaneously, and only use the needed fixtures.
In this case, After turning off the fixtures, I always reset the unit by the circuit breaker for my water heater for a short time. And then I turn it back on. This process gives me good results and my water heater should stay on.
In case, the problem constantly happens due to system overload, it signifies that you need to upgrade your water to a higher capacity one.
If you are using an electric tankless water heater system, you can switch it to the gas model. A gas water heater tends to have more capacity when it is about dealing with a significant amount of hot water demands.
03. Low Water Flow
Now at this point, let’s highlight one of the major points why your tankless water heater shuts off constantly. That is bad water flow. Yes! You get it right! If there is lower water flow than the minimum requirement, the heater fails to stay on or even won’t turn on at all.
During the troubleshooting steps, there are a few points that you need to concentrate on.
Here you go with the needed fixing steps:
i) The Water Shut-off Valve Is Not Opened
As for the first step, check whether the water shut-off valve for your Rheem tankless water heater to see whether it is open all the way or not. If not, just turn the valve lever counterclockwise to allow water to flow into the unit at full pressure. Also, check for obstruction in the water supply line and remove it.
ii) Obstructed Water Filter
Almost all the Rheem tankless water heaters equip a water filter that is mainly used to remove scale-forming minerals and sediment from the water. In such a way, it protects your tankless water heater from corrosion and diminished efficiency.
But as it is always in contact with the hard water, accumulating the hard particles in the filter from the mineral is quite obvious. This creates blockages in the filter which interrupts the normal water flow to the unit.
How To Fix:
Cleaning the clogged water filter is the only way to get rid of this problem. For instance, unscrew the water filter from the connection and clean it with running water.
If you find too much grim and hard particles there, you need to use a brush to clean the water filter effectively.
iii) Clogged Water Flow Sensor
The water flow sensor in the Rheem tankless water heater is an essential element that identifies the hot water demand and gives a read to the control board.
In case the water flow sensor starts malfunctioning, it will fail to give the actual water flow measurement to the controller, and why the heater may shut off randomly. Even at times, you may encounter an Rheem error code in the display as well.
How To Fix:
Check the water flow sensor to see whether it is jammed. If so, pull it from the connection and clean it properly with a toothbrush and vinegar. After cleaning, re-install the sensor back in place.
Now connect your Rheem tankless water heater to the power connection.
After ensuring all the above processes, we can hope your Rheem tankless water stops cycling on and off and get back into normal operation.
If not, you need to go through a deeper inspection. As such, the procedure will differ from the gas model and the electric model. Get details below.
Rheem Gas Tankless Water Heater Keeps Turning Off [4 Easy Solution]
First up, let’s highlight what are the other root reasons that are causing your Rheem gas tankless water heater keeps shutting off with the effective solutions:
01. Interruption In Gas Supply
If your Rheem gas tankless water heater keeps shutting off, an interruption in the fuel supply would be one of the root causes to blame for.
As your water heater is gas operated, it requires a fluent fuel supply in order to run efficiently. In case, if there is any interruption in the gas connection, be sure it’ll be the source of the problem when you are dealing with a malfunctioned tankless water heater.
Now various points can prevent your heater from getting enough gas. Either you don’t have sufficient gas in the LP tank or the gas supply for your water heater is being cut off.
Other major reasons would be:
- The gas shut-off valve is not open all the way
- Obstructions in the gas supply line
- Air in the gas line
- Otherwise, it may be an issue with the gas pressure.
How To Fix:
Start by inspecting the gas supply connection to your water heater. Make sure the gas supply is not being cut off or there has sufficient fuel in the LP tank. If needed, refill it and then purge the air from the gas line.
Then, look for obstruction in the gas supply line. Just remove the obstructions to ensure a fluent gas flow to the unit. When done, head to the gas shut-off valve and turn the valve lever counterclockwise to the “On” position.
Finally, you need to ensure proper gas pressure for your water heater. For instance, take a gas manometer and measure the gas pressure going through your unit.
Go through the manual for your Rheem tankless model and if you have any manual in the gas pressure measurement, adjust it to the recommended level. If needed, seek professional help to perform the tank for you.
02. Air Blockage
If there is all okay from the gas supply to your water heater and still the power is failing to stay on, check whether you’re experiencing blockages in the airflow. Unlike other tankless water heaters, Rheem gas tankless water heater also requires fresh air to fuel the combustion inside and blow it outside the house after ignition.
If there is no proper air circulation throughout the unit, the fresh air fails to enter the combustion air. Also, the combustion gas doesn’t pass out of the system which overheats the unit.
This results in the Rheem tankless water heater keeps going out. Plus, due to a lack of oxygen, the burner won’t ignite at all.
Whatever the fact is, it’s essential to figure out the actual reasons that are causing air blockage in the system.
Here you go!
03. Blocked Air Screen Filter
A blocked air filter screen is the root culprit for why there is a lack of combustion air in the system. The air filter screen is the major element that is designed to keep the bugs and dirt out of your system.
As it is always in contact with dirt, debris, and lint, clogging the screen is quite obvious which lowers the airflow to the unit.
But there is nothing to worry about. A quick cleaning will be enough to resolve the issue.
How To Fix:
Here is all how you’ll clean the air filter screen:
Step #1: First off, unplug your water heater from the power connection. Now, remove the front access panel and set it aside.
Step #2: Then, locate the air filter screen from the top right corner of the inside panel.
Step #3: Unscrew the filter from the connection and rinse it thoroughly under running water to wash off all the filths and grim stuck on it.
Step #4: If needed, use a brush to clean the screen properly.
04. Blocked Venting
Along with the air filter screen you need to concentrate on the system of the water heater as well. It is one of the major parts for proper combustion in the system which needs to inspect and clean on a regular basis.
Anyway, if it long time since you have not cleaned the vents of your gas tankless system, be sure the vents might be blocked with shoots, dirt, and debris that is causing the heater to turn off randomly.
How To Fix:
Inspect the venting system for any blockages, take a vacuum cleaner attached to an extension hose, and insert it into the vents. Gently vacuum out all the specks of dirt from the inside. If needed, use a duct cleaner for better cleaning.
05. Too Short Venting
Along with the cleanliness, you need to ensure the proper sizing of the venting. At times, improper installation of the venting causes air blockage in the system.
For instance, make sure that you’ve installed the vents in the correct order. If needed, go through the manual or contact Rheem customer service for better suggestions.
06. Dirty Burners/Igniter
If your Rheem gas tankless water heater keeps turning off, be sure there are some malfunctions from the ignition packs. Higher chances are the burners are blocked by debris that is preventing the flame from staying on.
Along with other elements, you need to inspect the burner orifice of your tankless water heater on a regular basis to check for any obstructions or damages.
If the orifice is filthy, you will never expect a healthy flame which eventually causes the water heater not to function efficiently.
Besides burners, the igniter is another susceptive element that would cause the issue.
If the igniter is damaged or blocked by soot, it will fail to create sparks on the tip, and for why the heater won’t stay on longer.
How To Fix:
Here is all to deal with the malfunctioning burner and igniter to keep the unit operating at peak performance:
Step #1: Clean The Burner Orifice
Cleaning your Rheem tankless water heater burner is a simple chore since you know the right procedures. Start by disassembling the water heater.
For instance, turn off the power supply to your water heater. Also, turn off the gas and water shut-off valve to your unit.
When done, remove the front cover to access the inside panel. Now locate the burner assembly and remove the three screws on the bottom back wall to pull the burner assembly out of the chassis.
Now take a compressed air and blowback down through all burner ribbons. Then, inspect the manifold fuel rails on both sides of the burner for any debris or clogging.
Now, clean with compressed air by blowing back through the nozzle. If needed, use a small needle or fine wire to clean the openings.
Step #2: Clean Out The Igniter
After cleaning the burner orifice inspect the igniter and flame rod for any damage. Use steel wool, emery cloth, or fine sandpaper to clean the ends of the igniter/flame rods.
But here make sure you are not damaging the ceramic base. Also, ensure a sig connection of all the igniter wires and flame probe wires to the PCB.
07. Plugged-Up Heat Exchanger
Last but not least, the plugged heat exchanger is also in the row of the major reasons why your Rheem gas tankless water heater is not staying on.
Whether you have a condensing or non-condensing Rheem tankless water heater, it equips one or two heat exchangers that are highly responsive for heating the water and ensuring running the heater efficiently.
But the heat exchanger tends to be plugged up easily by hard water minerals. This mainly happens if you are living in a hard water area.
While the heating process, the natural minerals from hard water pass through the heat exchanger fins and settle down there.
After a long time, all that turns into hard particles and loses its efficiency.
Deposits inside the heat exchanger cause to raise the inside temperature to an extreme level which turns off the system unexpectedly.
How To Fix:
Descaling and flushing out the heater is the only way to deal with the plugged-up heat exchanger. Flushing out the tankless water heater is straightforward and you can do it by yourself.
Also, you need to be regular to flush out the system once or better twice a year to maintain the functionality of the heater. Anyway, look at our comprehensive guide to learn the effective process to descale & flush your Rheem tankless system without even the help of a pro.
Rheem Electric Tankless Water Heater Keeps Turning Off [Reasons + Solutions]
If you have a Rheem electric tankless water heater, here are a few more major points that you need to concentrate on:
01. A Faulty Breaker
If your Rheem electric tankless water heater fails to stay on, a higher chance is it keeps tripping the breaker. If that is so, a faulty breaker is one of the root culprits to blame for this issue.
Keep note that, the usability of the circuit breaker certainly declines after a few years of usage. According to the Consumer Product Safety Commission (CPSC), the lifespan of the CB is approximately 30 to 40 years.
Even before reaching its life span, the problem starts when you are not ensuring the right size of breaker according to your tankless water heater. Smaller amp circuit breakers cause overload in the system that overall reduces its efficiency over time.
Whatever the fact, When you are dealing with a defective circuit breaker, it will constantly trip even before reaching the specified current limit.
How To Fix:
Head to the circuit panel of your house and locate the dedicated breaker switch for your tankless water heater. Flip it to the “Off” position, as safety is first! Now take a multi-meter and test the continuity of the breaker.
If the result shows negative, you need to replace the breaker ASAP. While doing that, make sure you are getting the right size of the breaker for your water heater.
02. Bad Heating Elements
If still, your Rheem electric tankless water heater is not staying on, be sure you are dealing with internal component failure in the system. Here one of the most common reasons would be the malfunctioning of the heating elements.
Unlike other electric tankless models, Rheem tankless water heater equips two robust copper immersion heating elements with a brass top for heating purposes. In case the heating elements fail, it will not only stop heating the water but cause the circuit breaker to trip constantly.
There are various reasons why the heating elements may fail.
Either there would be a short circuit or physical damage. There is also a situation where the heating element is working when it is not supposed to. This results in getting the water too hot which trips off the circuit of the heater, shutting off the water heater.
How To Fix:
Before assuming the heating element is faulty, it’s always advisable to test the elements electrically. Take a multimeter and verify the continuity. If the results show negative, nothing but you need to replace it to get your heater back into normal functioning.
FAQs:
How to fix the malfunctioning flame rods in a Rheem tankless water heater?
First off, inspect the burner chamber for any blockages that are blocking the flame rods and clean it. Check the flame rod for proper voltage. And finally, ensure it is touching flame when the unit fires.
Why is there a communication fault with the remote control of my Rheem tankless water heater?
If the remote control malfunctions, look for loose or damaged connections there. If needed, replace the faulty cable. Remove your heater power cord from the 3 prong outlet and disconnect the remote control. Then test the heater without Remote Control connected.
How to access the maintenance mode of my Rheem tankless water heater?
To access the maintenance mode, turn the unit OFF at Remote Control and turn off the water flow as well. Hold down the UP and DOWN arrow keys simultaneously for 5 seconds. You will hear a beep sound with all the information on the display.
In Closing
After thoroughly reading, we hope you are now all clear about all the responsive factors behind the Rheen tankless water heater that keeps turning off. Also, we’ve well-decorated our comprehensive guide with proven fixes that assist you in getting rid of this problem without seeking pro help.
But yet we recommend not dealing with a short circuit or damaged wiring by yourself. It’s better to hire an electrician to ensure the best task for you.
Well! That’s all from us here today. If yet not or if any other problem appears, you can take a look at our well-proven guide on Rheem tankless water heater troubleshooting.