Navien Tankless Water Heater Humming Noise [Fully Explained]

Hearing any abnormal sounds from your water heater will surely get you worried. Especially, if it’s a humming noise and it lasts for a while. So what causes the Navien tankless water heater humming noise?

Having worked on many Navien water heaters over the years, I can tell you that the main reasons behind it are:

  • A clogged or faulty blower fan.
  • Dirty heat exchanger.
  • Loose parts inside the water heater.
  • Gas supply issues.
  • Inadequate ventilation.
  • Disrupted water flow.

Apart from them, there are many other reasons that can lead to this issue in your water heater. I’ll talk about all of them in this guide along with the solutions. You’ll also learn how to take better care of your water heater to avoid this issue in the first place. So, let’s dive in!

navien tankless water heater humming noise

It’s normal for tankless water heaters to make a little noise when they start up and heat the water. But those noise levels are tolerable and they wouldn’t bother you much.

However, the noise coming on when the water heater isn’t used is a cause of concern. On top of that, the sound being too loud or the water heater vibrating are also issues that you should look into.

I’ve compiled a list of the most common reasons behind your Navien tankless water heater noise problem. Let’s take a detailed look into all of them along with the fixes in this section.

01. Clogged Or Faulty Blower Fan

There’s a blower fan inside the Navien tankless water heater. It’s a necessary component for proper combustion. It makes sure that the combustion air goes into the burner and the exhaust gases go through the exhaust pipes. So, it shouldn’t come as a surprise that this fan gets dirty with time.

One of the main reasons why you’d hear the humming noise from your water heater is due to a clogged fan. It could be due to dirt. Sometimes, small insects or lizards can also get inside the fan and make it clogged.

No matter what the reason is, you’d hear the humming noise when your fan won’t spin properly. So, try to hear the sound properly and see if it’s coming from the area where the fan is. If that’s the case, then there’s a strong likelihood your fan is clogged.

How To Fix:

You’d have to clean the fan if it has gotten dirty. Don’t worry, it’s not a hard job at all. I’ve done it many times and you can do it too if you follow the right steps to clean the blower fan. Here’s a rundown of the process you need to follow:

Step 01 – Locate The Fan

Turn off the power to the water heater and unplug it from the power outlet.

Remove the four screws that hold the front cover in place and take it out.

Locate the blower fan at the top of the water heater. If you’re having trouble locating it, here’s a picture to help you out:

blower fan of navien tankless water heater

Step 02 – Remove The Fan

Remove the screws attached to the fan. There will usually be three screws holding the fan in place. Then, disconnect any wiring connected to the fan so that you can pull it out. Remove the fan and blow compressed air into the fan to get the dirt out of it. 

Step 03 – Reinsert The Fan

When you’re done cleaning the fan, you can put it back in its original place. Then, tighten the screws and wiring connections to make sure it stays in its position and works properly.

That’s how easy it is to clean a fan. The only thing left to do is to restore the power supply to your water and see if the humming noise goes away. Hopefully, it will go away immediately after cleaning the fan.

If it still remains, it’s likely that you have another issue with your heater. In that case, you need to keep diagnosing the issue so that you can find the real culprit. So, let’s keep looking at the other reasons behind this problem.

02. Loose Parts Inside The Water Heater

All the parts in your Navien tankless water heater have to be installed tightly.  If any of them come loose, it can cause your water heater to hum. Moreover, the parts inside the water heater can also get dirty and create noise.

The most obvious sign that you’re facing this issue is if you see the water heater vibrating. The motion of vibrating indicates that something has come loose inside the water heater.

If you hear a  loud vibration, remove the front cover of your water heater. Then, try to look for the part that’s shaking a lot. If you’ve found the faulty component, you’ve already solved half of the problem.

How To Fix:

Once you find the loose component, your job is to tighten it. Use a wrench to tighten the loose fittings and make sure the connection is secure this time.

If you find that the inside of your water heater is extremely dirty, it’s also a good idea to clean it. That’s all you’ll have to do to get rid of the humming noise if the reason behind it is a loose part.

03. Dirty Heat Exchanger

One of the most common reasons behind your Navien water heater making a humming or buzzing noise is a dirty heat exchanger. It gets dirty with time as sediments and minerals pile up on it.

heat exchanger of navien tankless water heater

It’s not just the heat exchanger but even the pipes can get affected due to sediment build-up. You’ll face this issue more frequently if you live in an area that has a hard water supply.

Whenever the humming noise arises due to this issue, it’s a cry for help from your water heater. The heat exchanger will be severely clogged and can even get damaged if you don’t do anything to fix it soon.

How To Fix:

There’s no reason to be in a total state of panic if there’s a build-up of sediments on the heat exchanger. All you have to do is to flush the heat exchanger. You can follow these steps to do it:

  1. Turn off the water heater, unplug it from the power outlet, turn off the gas supply, and close the water supply.
  2. Remove the front cover of the water heater and drain the water heater. I recommend that you clean the water inlet and recirculation filter while you’re at it.
  3. Pour the cleaning solution you’re using or 5 gallons of white vinegar into a bucket and connect it to the recirculation pump.
  4. Let one end of the recirculation pump go to the water heater and leave the other end in a position where the solution can come to the bucket.
  5. Let the recirculation pump run for 30-45 minutes. Once that period passes, you can turn it off.
  6. Disconnect the recirculation pump and open the hot water faucets. Restore the power supply of the water heater and use it.

So, that’s how easy it is to flush the heat exchanger in your Navien water heater. I have a guide on flushing a Navien water heater that you can check out if you want more detailed information on it.

Remember that it’s a good idea to flush the heat exchanger at least once every year. If you do that, you’ll be preventing many potential problems in your Navien water heater that could have happened otherwise.

04. Abnormal Dual Venturi Operation

Another component that’s connected to the fan assembly is the dual venturi. It’s attached to the underside of the fan motor where the gas pipe comes off the gas valve. Hopefully, you’ve located it by now.

You’ll see the error code E060 on the Navien water heater when this issue occurs. You can test the dual venturi assembly to see if it’s still functional. Follow these steps to test it:

  1. Press the “Wrench” button on the keypad of your Navien water heater and hold it for five seconds until you some letters being displayed on the screen.
  2. Tap the “+” button a few times until you see the letters “DVE” on the screen.
  3. Then, you can press the “Mode” button, and the letters “ON” should come on the display at this stage.
  4. Once you get there, you should hear some movements every time you press the “+” or “-” button.
  5. You’re supposed to hear a clicking noise shortly after you hit the button.
  6. Press the power button to get out of this testing mode.

If you don’t hear a clicking sound or the dual venturi continues to move, then it’s faulty. If it continues to move instead of making just one clicking noise, you can also conclude that it’s bad.

How To Fix:

The dual venturi assembly needs to be replaced if it’s faulty. It’s highly likely that Navien will send you the entire fan assembly if the dual venturi is bad. So, you don’t have to worry about replacing it as an isolated unit.

You already know how to remove the fan assembly if you’ve followed this guide serially. Instead of cleaning it and putting it back in, you’ll just replace it with a new one. That’s how you can stop the humming sound in your Navien tankless water heater.

05. Water Siphoning

There’s nothing unusual about a water heater making a little noise when it calls for hot water. That’s a part of the normal operation of the water heater. But when it makes a noise even when there’s no demand for hot water, that’s a cause of concern.

It’s possible that water siphoning could be the potential culprit here. You can check the other hot water faucets in your house to see if this could actually be the issue. 

How To Fix:

If you’ve figured out that you have this issue, you need to install a check valve. Doing that will make sure that the faucets don’t interfere with each other. Hopefully, that’ll also get rid of the humming noise.

I’d recommend that you let a professional plumber handle this job if you don’t have the technical expertise to do it yourself. Make sure you instruct the plumber to separate the hot water faucets and the other ones.

06. Gas Supply Issues

You may find it to be crazy but even a lack of gas supply can lead to your heater making a humming noise. If I am being honest, it’s more of a rumbling or whistling noise with a relatively low frequency.

gas supply issues of navien tankless water heater

This issue with Navien water heaters is particularly annoying as you’d hear this noise in your entire house through the walls. That’s one of the downsides of not using shock absorbers to isolate the water heater.

There are several potential mistakes when it comes to issues related to gas supply. The most common issue is to use gas lines of the wrong size. The other mistake is to not open the gas valve fully.

You may want to change the gas type of your tankless water heater. Another common mistake is to convert an LP heater to a natural gas water heater incorrectly. The reverse of all that is also a mistake. 

How To Fix:

First of all, you have to make sure that the gas line leading to your heater matches the recommendation of Navien. Don’t mess around with the gas settings in your water heater if you don’t have the gas line of the right size. It’ll only make the problem worse.

Make sure you change the gas line depending on the instructions in your owner’s manual. Hopefully, that’ll be enough to solve the issue.

Inspect the gas control valve in your house and make sure it’s turned on all the way. A gas control valve is turned on when it’s fully parallel to the gas lines. If it’s only partially parallel, make sure you turn it all the way. Doing that may solve the humming noise issue.

Also, keep in mind that Navien has clear instructions and conversion kits on the heaters where you’re allowed to change the gas type. You need to follow those instructions properly so that you won’t run into any issues later when changing the gas type of your water heater.

07. Dirty Air Intake Filter

The humming noise is often created by a fan that’s not operating properly. One of the reasons that could cause that issue is when the air intake filter is dirty. You can see the error code E109 come up on your water heater when you’re facing this issue.

air intake filter of navien tankless water heater

The air intake filter gets dirty with time as there are impurities in the air. In severe cases, insects, bird nests, and wasps could get caught up in it. You may also find tree leaves if your air intake pipe leads outside your house.

How To Fix:

This problem has an easy fix. All you have to do is pull out the air intake filter and clean it. You can easily do it on your own without the assistance of a qualified technician. Follow these steps to do it:

  1. Turn off the power to the water heater and unplug it from the power outlet.
  2. Remove the four screws that hold the front cover in place and remove it.
  3. Locate the air intake filter at the top of the water heater right under the air intake pipe.
  4. Remove the set screw holding the air intake filter in place and loosen the other screw connected to the pipe.
  5. Remove the air intake filter and clean it under running water. If rinsing it doesn’t clean it all the way, you can use a toothbrush to get the dirt out.
  6. Reinsert the air intake filter in its original position after cleaning it and tighten the screws to secure its place.
  7. Attach the front cover of the water heater and restore the power supply to the water heater.

That’s how easy it is to clean the air intake filter on your own. You should clean the air intake filter once every few months so that your water heater operates well. Hopefully, the humming noise issue will go away once you clean the air intake filter. If not, keep on diagnosing.

08. Abnormal Air Pressure

Many of the issues that lead to the humming noise are the direct result of an imbalance in the air of the water heater. When there’s something wrong with the air pressure, you can hear that annoying humming noise from your heater.

You already know about some of the reasons that this issue is caused. It could be due to a faulty fan or a clogged air intake filter. However, it could also be the result of the presence of obstructions in the exhaust pipe.

How To Fix:

You already know what to do when something goes wrong with the air intake filter or the fan is dirty. When there are obstructions in the exhaust pipe, you need to remove them.

Go about solving this issue the way it suits you the most. The approach can be a little different depending on how your exhaust pipe is set up. The important thing is to get the dirt out. Once you do that, I hope that the annoying humming noise issue will go away.

09. Disrupted Water Flow

Your water heater is likely to make a humming or screaming noise if it doesn’t have a proper water flow. The most common reason behind disrupted water flow is not opening the valves all the way.

If you don’t open fully open the valves, the water will be forced through a very small area. So, the pressure will be high in that area and that’s why you’d hear the squealing noise.

How To Fix:

Thankfully, this issue has a simple fix. Since the problem is that the valves aren’t fully open, all you have to do is open them all the way. You’d have to check each of the valves until you isolate the faulty valve. Once you tighten the loose valve, the humming noise should go away.

10. Too Much Air

Your Navien tankless water making a noise is never a good sign. But it’s even more scary if the noise is coming from a fairly new heater that has only been used for a few months.

I know someone who had his Navien water heater making a screaming noise only after using it for three months. The model of that tankless unit was 240A. The main reason behind this issue is when too much air has accumulated inside the water heater.

How To Fix:

Luckily, this problem can be fixed easily. You’ll see an air bleeder valve at the bottom of your Navien water heater if you look carefully. Here’s a picture so that you can get an idea of the part:

air bleeder valve of navien tankless water heater

Simply unscrew the air bleeder valve and let the water and air out of the heater. If you let it drain for a few minutes, the air will no longer be in the system. Put the valve back on when you’re done and the screaming noise should come to an end.

11. Leaks In The Water Lines

It’s possible that you’d hear a humming or hissing noise if there’s a leak in any of the water lines of your water heater. While it’s a serious issue, the procedure to test leaks is fairly straightforward.

All you have to do is turn off the cold water supply for a while and turn it back on. If the water travels at a normal speed, it means there’s no leak. But if there’s a sudden rush of water, you can tell that there’s a leak.

How To Fix:

Issues like leaks in the water line can be a complex and serious issue. It needs to be solved at a root level rather than sealing the leak as a temporary solution. So, contact a professional plumber to sort out this issue for you.

12. Dirty Flow Sensor

The sensors in your water heater need to operate properly so that the water heater stays in good condition. If the flow sensor in your water heater malfunctions due to any reason, it can lead to a knocking noise.

flow sensor of navien tankless water heater

The main job of the flow sensor is to keep track of how much gas enters the water heater is operational. If it doesn’t do that correctly, the water heater will not have the right amount of gas. Hence, the water heater won’t work properly.

The most common reason behind a malfunctioning flow sensor is when it gets dirty. It’s due to the dirt piled up on the main part of the sensor that it can’t get the right reading. Besides, they can also get damaged at times.

How To Fix:

The solution is simple – clean the flow sensor. Hopefully, that’ll take care of the problem. If your water heater still makes the noise, you can replace the flow sensor to solve the issue.

13. Water Hammering

If you can’t isolate the noise from the water heater, check the pipes. The noise can come from the pipes when there’s a case of water hammering. It’s a state where the water heater pipes bang too loudly and create noise.

There are a few reasons behind this issue. The main one is if the pipes aren’t connected in a secure manner. Secondly, too much water pressure inside the pipes can also cause water hammering.

Finally, turning on too many hot water faucets at a time will also increase the pressure of the water heater. It’ll also lead to water hammering. If you only hear the annoying noise when you turn on many faucets, this could be the issue you’re facing.

How To Fix:

Water hammering isn’t a serious issue that you need to correct right away. Yes, you’ll be annoyed when your water heater makes noise. But apart from that, it’s not something you need to act on immediately and take steps to solve it. 

Installing water hammer arrestors is the most efficient way to solve this issue. They’re little parts that you can install to relieve the pressure in the pipes. You can install them on both hot and cold water lines. It’s important that they have to be installed in the right locations.

water hammer arrestor of navien tankless water heater

You’d have to put them in the areas that are more prone to be affected by the water hammering issue. It’s unlikely that you’d be able to figure such spots on your own. So, I suggest you hire an expert plumber to help you with this one.

14. Inadequate Ventilation

It’s not the most common reason behind the humming noise in a Navien water heater. But I’ve seen it happen a few times over the years and that’s why it’s also worth mentioning.

The area around the water heater needs to be free and clear of any dirt. There should be sufficient clearance between the heaters and the objects next to it. Otherwise, the heater won’t have proper breathing room and it can lead to noise in some cases.

On top of that, the ventilation process can also be obstructed. Water heaters can also make a loud noise during that time.

How To Fix:

This issue is one of the easiest ones to fix. If there’s dirt around the area where your water heater is located, do a thorough cleaning job. If the water heater itself is dirty, you can clean it too.

Secondly, you have to check for obstruction in the ventilation. If there are any unwanted objects in any of the intake or exhaust pipes, you need to remove them. Make sure the connection of the vent pipes is secure as well.

If the humming noise stops after you do that, you’ve found the culprit and fixed the issue. If there’s not enough clearance for the water heater, move the objects next to it further apart. Especially, if there’s any object that’s directly touching the water heater.

It’s also a good practice to clean the heater and the area around it from time to time. If you’ve read this guide so far, I’d recommend that you try this solution first to get rid of the humming noise.

I’ve designed this guide in such a way that the most common reasons appear first. But this one is just an easy fix that you should try right away. If it works, you’re in luck. If not, then you already know about the other major reasons behind this issue.

What Causes Navien Tankless Water Heater Recirculating Pump Noise And How To Fix It?

The Navien humming noise can also come from the recirculation pump. It’s completely normal if the recirculation pump makes a little bit of noise. But if the noise gets too annoying, you need to look into it. Let’s understand the main reasons why the Navien recirculating pump makes noise.

recirculation pump of navien tankless water heater

i) Incorrect Primary Loop Installation

If you’re facing this issue in a fairly new water heater, not installing the primary loop correctly is a common culprit here. If the plumber who installed the loop sets the tees backward, the pump won’t work.

Not mounting the pump securely can also make it vibrate and cause an annoying humming noise. For the combi boilers, the returning water can mix with the boiler loop system and cause this issue. Using the pipe of the wrong size can also cause this humming noise in the Navien water heater.

How To Fix:

Check the primary loop and see if the tees are set backward. If they are, then 

adjust them to the right position. You have to double-check that the pump is mounted securely. You can do two things to separate the recirculation pump from the other components and ensure it doesn’t cause any noise.

Firstly, use a thick rubber between the pump and the area where it’ll be mounted. You can also use a flex connector to separate the pump from the other components. 

Make sure you’re using a pipe that’s  1-½ inches for the horizontal manifold. If you don’t feel comfortable doing it yourself, you can consult a professional plumber for this job.

ii) Not Bleeding The Recirculation Pump

You need to purge the recirculation pump and get the air out of it from time to time. If you don’t do that, it’s common to hear a humming noise coming from the recirculation pump in your Navien water heater.

How To Fix:

The solution is straightforward – you’d have to purge the recirculation pump. Thankfully, the process of doing it is extremely easy. Start by locating the air bleeder valve at the top of the recirculation pump.

Then, all you have to do is to loosen the cap so that air can get out of the system. Once that’s done, tighten the cap again. Make sure you don’t go too long without bleeding the air again to prevent this issue from happening again.

iii) Obstructions In The Pump

It doesn’t happen often but there are rare cases when obstructions like small pebbles or other dirt can get inside the recirculation pump. The humming noise you’d hear in this instance is of these things banging against the pump.

How To Fix:

If you suspect that this could be the issue, try to listen to the recirculation pump better. Notice if you hear any movement of objects. If your suspicion rises further, there’s only one way to find out about it.

You’d have to disassemble the recirculation pump and check if any foreign materials have gotten inside it. Clean the pump if you find such stuff and put it back together.

How To Prevent Navien Tankless Water Heater From Making The Humming Noise?

It’s nice to know about the fixes when you’re facing an issue. But it’s always better to prevent those issues from happening in the first place. Whenever your Navien tankless water heater makes a noise, it’s usually due to an imbalance in the water heater.

So, the key to making sure that you don’t hear that annoying noise is to maintain the water heater well. There are many maintenance tasks you should perform on your water heater.

The most important one is to flush the heat exchanger in your water heater. It’s an easy process if you know what you’re doing. You only need to do it once or twice a year depending on the hardness of the water in your area. Check out my detailed guide on flushing the Navien water heater to learn more about it.

flushing the heat exchanger of navien tankless water heater

Besides flushing the water heater, there are several other maintenance tasks you should perform. For example, cleaning the area around the heater and the air intake filter is important for Navien tankless water heaters.

Following those things should keep the possibility of that humming sound at a minimum. If you truly want your heater to last for a long time, you’ll have to take proper care of it. You’ll need to follow more maintenance tips for that.

Luckily, I have just the thing you need. I’ve prepared a detailed guide on maintaining your Navien tankless water heater. You’ll find everything you need to know about all the maintenance procedures. So, make sure to check it out and follow the tips if you want to increase the lifespan of your water heater.

Can You Take Additional Steps To Stop The Humming Noise?

Maintaining your heater will reduce the possibility of your Navien water heater making a noise. It’s also a step in the right direction to get the most use of your water heater. But if that’s not enough, I’ve got some additional tips for you to stop the humming noise. Let’s take a look at them.

01. Use Rubber Gaskets Or Anti Vibration Mounts

The sound your water heater makes will normally have a major impact on your house. That’s because most tankless water heaters are mounted directly to the wall. So, you’d hear the noise throughout your entire house.

But you can reduce the level of sound by a great deal if you choose to install rubber gaskets or anti-vibration mounts. Neoprene or Rubber are used to make such anti-vibration mounts and you can install them to lower the noise.

If you use them, the humming noise will be limited to the water heater. It won’t travel through the halls as it normally would have otherwise. You can also place a rubber gasket between the walls and the tankless water heater to limit the sound.

Hopefully, that’ll do the trick. That’s an easy hack that anyone can implement. Another thing you can do is to place a piece of foam between the heater and the walls. You can use it as a temporary solution and it should also reduce the noise by some degree.

02. Use Soundproofing Material

If you don’t want to install anti-vibration mounts or rubber gaskets for any reason, another option is to use soundproof material. You can install things like rock wool insulation or acoustic foam around the water heater to reduce the sound coming from it.

So, those were the two easiest additional things you can do to turn down the noise your water heater makes. Honestly, the first solution is much better than using soundproofing material.

Because it directly reduces the sound that would otherwise travel through the walls. I am sure you’ll notice a big impact if you install anti-vibration mounts or rubber gaskets. So, give it a try so that your ears can have an easier time.

What Causes Navien Tankless Water Heater Beeping?

Apart from the humming noise, you may hear the water heater beeping. I’ll talk about why Navien and other tankless water heaters in general make a beeping noise. Let’s take a look at them.

i) Water Leaks

The most common reason behind a tankless water heater beeping is leaking water. It can be very easy to spot water leaks sometimes. If you find a pool of water puddled around the area where your tankless water heater is installed, you can confirm that there’s a leak.

water leaks of navien tankless water heater

But the leak won’t always be so easy to detect. Sometimes, the leak can be somewhere in the line. So, you’d have to go into detective time and find the area of leak in such cases.

If there are leaks, you need to take the appropriate steps to seal the leak. Turn off the water heater first and then, clean the water. Try to identify the leak source as early as possible and fix it.

If there are no leaks, the problem can also be with the leak sensors of the water heater. If the leak sensor is faulty, it needs to be replaced. You’d have to check what’s causing the issue and fix it. 

ii) Scale Build Up

You already know about the presence of minerals in the water that goes into the tankless water heater. They can make the heat exchanger malfunction with time. Your water heater may sometimes beep due to this reason. The solution is to flush the heat exchanger and you already know how to do it.

iii) Excessive Pressure

You can only push your tankless water heater to a certain limit. As it produces hot water on demand, it can’t give you an unlimited supply of water. If you open too many hot water faucets at the same time, you’ll overload the system. Hence, the water heater may make a beeping sound.

The solution here is to turn off the faucets and lower the demand for hot water use in your house. Make a plan with the other members of your home so that there’s minimal overlap when using hot water.

The heater can also get overheated during this time as it has to work harder. The heat exchanger will generate a lot of heat and it could cause further issues. So, you’re always better off keeping the number of active hot water faucets down to the least you can.

iv) Air Intake Or Exhaust Blockage

If the combustion process of your water heater is interrupted, it won’t be able to produce hot water effectively. Even if it produces hot water, it will happen at a much slower rate.

One such reason behind the combustion process not going smoothly is obstructions in the air intake or exhaust blockage. If the air intake has blockage, the heater won’t be able to draw in enough air for combustion.

If the exhaust is blocked, it won’t be able to get rid of the exhaust gases completely. So, inspect those areas for bird nests, dead insects, dust, and lint. If you find any blockages, clean them.

v) Low Flow Rate

You know how opening too many hot water faucets can increase the flow rate and cause issues with your water heater. Just like that, a low flow rate is also bad and can cause your water heater to make a beeping noise.

You’ll be able to check the minimum flow rate required for your water heater. Its unit is GPM or Gallon Per Minute. If the flow rate is lower than the recommended amount, you’d barely get any hot water.

A low flow rate is also dangerous because the water can easily become overheated. Since it’ll be passing through the heat exchanger for a longer period, it’ll be more hot than you desire. So, check the flow rate and fix it if you’re facing this issue.


Are there any error codes if your Navien fan motor goes bad?

Yes, certain error codes pop up on the display of your Navien water tankless water heater if the fan goes bad. The error codes E009, E010, and E027 all indicate that the fan motor is malfunctioning.

Can the humming noise in the water heater be caused only by water supply issues?

While water issues can cause the humming noise, it’s evident that other problems can also make the noise. Gas supply and ventilation problems can also cause it. You need to diagnose them both properly as shown in this guide.

What kind of minerals are accumulated on the heat exchanger of a Navien water heater?

It’s usually Calcium and Magnesium that pile up on the heat exchanger of your water heater. You have to flush the heat exchanger at periodic intervals to make sure it doesn’t get damaged.

Should you use a water softener to protect the heat exchanger from getting clogged?

Installing a water softener will surely help if you live in an area where the hardness of the water is high. If you feel the need to flush the heat exchanger once every six months, I’d recommend using a water softener.

Will the water heater make a humming noise if it’s not mounted correctly?

Yes, your Navien water heater needs to be set up securely in its position. If it’s loose, you’ll hear a humming noise from it. In that case, you’d have to install the water heater tightly to eliminate the noise.


Now, you know the main reasons that cause the annoying Navien tankless water heater humming noise. Be patient with the diagnosis until you find the culprit and solve it when you do. Hopefully, it’ll be a simple issue that you’ll be able to fix easily.

Follow the maintenance procedure and additional precautions to prevent this issue from occurring in the first place. Another common problem is that your Navien water heater makes a loud banging noise. Check out my guide on it to learn how you can solve that issue.

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