Tankless Water Heater Beeping (10 Common Issues)

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Written By John Roe Stephen

If you just installed one, you may hear a beeping sound coming from your tankless water heater. There is a variety of causes for this.

The most probable scenario is that someone tried to use the incorrect size, ran out of fuel, improperly vented, or had sediment buildups. The good news is that you do not need to call in a plumber since we have you covered.

The following are possible causes of beeping from the tankless water heater.

1. Insufficient Capacity of Tankless Water Heater

Getting rid of the beeping noise requires careful consideration of the tankless heater’s size. The BTU rating of your tankless heater determines how quickly it heats the water.

Consequently, if you have chosen a smaller unit, you may not be able to heat enough water. As a result, water flow slows down and creates a distinct beeping noise.


This issue can only be resolved by purchasing a new, bigger unit.

2. Water Gas, Or A Defective Sensor, Might Be Leaking

Leaks can also cause water heater beeps. There might be a leak of water or gas. A water heater with a leak detection sensor may help prevent water damage to your home.

Water dripping from your tankless water heater’s casing is a sure sign of something wrong with your appliance. Now that you know where the leak is coming from, you need to find a solution. 

Dry the machine first, and see if that fixes the beep. If your product is under warranty, you must contact the manufacturer. Whenever the water heater bursts, here is what to do.


There is a gas leak if you detect a rotten egg odor coming from a gas-fired model. Call the gas company to turn off the gas supply.

3. Venting In The Wrong Way

Proper venting is necessary on all tankless water heaters for rapid and efficient functioning. Venting may be hindered if your gadget isn’t operating correctly and the average room temperature. Make sure there are no jams or obstructions to avoid this kind of trouble in the future.


You must use a tiny brush to clean your vent—problems with condensate drainage.

4. Aerator Or Inlet Blocked Or Low Supply

It’s important to remember the scale buildup we discussed before. Your incoming water line may be clogged and blocked by scales that can cause a reduced inflow to the water heater, leading to overheating if there isn’t enough hot water getting to the heat exchanger. As a result, the water heater emits a beep to inform the user.


However, how can you be sure of this? Have you discovered that your fixtures are putting out less water than you expect or that the water is coming out hotter than you expect? You have a stumbling hurdle.

5. Extremely High Levels Of Pressure

Check the pressure valves first before making any significant adjustments to your unit if it is constantly beeping.


Your water pressure should be between 80 and 120 pounds per square inch.

6. Overheating

Gas outdoor boilers are often misused, resulting in this problem. It may sound an audible alarm before shutting down or resetting if your tankless heater goes into its ‘Overheat Protection Shutdown’ mode.


Please take a few minutes for the gadget to cool down, then switch it back on.

7. Low Rate of Flow:

A lengthy beeping sound is made by your water heater when it senses low flow rates. There are several possible explanations for this. If the valves are not entirely open or there is a blockage in the pipes, it must be addressed promptly.


Find out whether the intake and outflow valves are entirely open.

8. You Can Find The Error Code By Searching For It

Look for the trouble number E-1 on the LED display. If you hear a beeping sound, your device is now in its default state and has to be reset or contacted by customer support.


Press and hold the “ON” button for approximately 10 seconds to restart the device.

9. Water Heater Descaling Is Needed

The water heater keeps water stored or circulates continuously in the case of a tankless one. In this water, elements such as calcium and magnesium may corrode metal parts like heat exchangers.

Over time, these particulates buildup and reduce water heating performance if the water entering your house is hard (meaning it has a high proportion of the components listed above).


Error code “LC” is the most often seen. However, it might vary from brand to brand. The sediments need to be flushed and descaled in this scenario.

When it comes to flushing your water heater, you have two options: you may follow this advice here, or you can call in the pros.

10. Failure Of The Ignitor

Many factors might cause your water heater to fail to heat up. Check whether the propane tank remains full before doing something else since a gas shortage often causes this problem. If your gas or water valves aren’t entirely opened, your ignition may stop working.


Verify and completely open all gas and water valves. Your ignition package may have broken, or there is a more serious issue if following these methods doesn’t fix the ignition problem.

If the problem persists, you should seek assistance from technical support, which may perform diagnostics and arrange orders for new components as required.

Tankless Water Heater Beeping 11

  • High Heating Pressure

The Navien error code E011 indicates that there is a lot of pressure on the side of the heater. Switching off the device, emptying the water, and turning it back on may cure this problem code.


Make sure the sensor is working correctly if the problem continues. Replacing the sensor is an option if the old one fails.

  • Water Adjustment Valve Abnormality

Navien error code E011 indicates that the water control valve is malfunctioning. The Navien code E011 might be generated by a water adjustment valve that is either open or too short.


Look at the valve’s condition and wiring before turning off the tankless water heater. Make a service call if required.

Tankless Water Heater Beeping 29

  • The Exit Temperature Of The Heat Exchanger Is Too Low

Check the heat exchanger for any buildups if your Rheem shows an error code 29. If the intake filter has to be cleaned, do so. Temperature sensors and PCBs may need to be replaced in your heat exchanger. 

The device should be operating correctly if the water temperature is indicated in the maintenance information.


The most common remedy for this error number is to remove any debris or clogs from the containers and drain line. The drain line must be free of any flat runs and 90-degree elbows.

Why Is My Tankless Water Heater Beeping?

A heater can sound a beep if it detects a water leak. If the floor is moist near the water heater, the leak may be visible, but it may also be somewhere else in the system.

One possible cause is a flood protection system, such as a water heater shutdown function. A gas leak may also be detected by beeping.


As a result, the next time your portable water heater beeps at you, you’ll know exactly the problem. So, have a look at the error message on the screen. An error code can help you determine the nature of your system’s problem.

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