Tankless Water Heater Maintenance – Problems and Their Solutions

In this guide, we have explained Tankless Water Heater Maintenance, the most common problems, and their solutions, exterior maintenance, and how often should you carry maintenance.

Tankless Water Heater Maintenance

The most significant feature of a tankless water heater is to provide hot water on-demand while saving energy more efficiently in comparison to the traditional tank-style water heater.

It is obvious that the more you take care of things, the more efficiently they will work. Similarly, a tankless water heater also requires routine maintenance. Both the inside and outside care matters for ensuring optimal operating efficiency.

Common Problems with Tankless Water Heater

By maintaining your tankless water heater you can easily avoid repair issues that can often occur. It helps to enhance the lifespan of the unit and conserves energy for efficient working.

The prominent factor that can cause problems is the hardness of the water. But by regular maintenance.

As you know that hard water is full of sediments, minerals, and calcium deposits, and these all result in scaling the inside of your unit. Hard water travels through pipes and reaches into faucets.

If proper maintenance is not being done over a specific period it can result in a heavy build-up of sediments damaging the whole functioning of your water heater.

How Maintenance is Beneficial?

You can schedule the maintenance and can also do it by yourself to perform its servicing. The major step of maintenance is cleaning the whole unit in different ways so no minerals and sediments can gather.

An inline filter can be beneficial for this purpose. These all maintenance ways can enhance the operating efficiency and effectiveness of your tankless water heater.

You can save yourself from extra expenditures over unnecessary wear and tear and the longevity of your water heater extends up to many folds.

If you want to know the maintenance difference between Condensing vs Non-Condensing Tankless Water Heaters, we have written an article on that too.

Supplies Required For Cleaning


Here’s the list of necessary things that are useful during the whole maintenance process:

  • Hoses
  • 5 Gallon Bucket
  • Descaler
  • Submersible Pump

You can buy these items easily or can get a flush kit that includes most of the items.


Descaling is a process of removing accumulated gunk stuck inside of your water heater system.

In an area where is plenty of hard water, the tankless water heater will require frequent descaling. In most cases, the minerals and sediments pile up in the system by causing a severe mess.

This process is quite similar to the flushing & cleaning that we are going to discuss next. Somehow, it involves water-vinegar to run through the unit. Vinegar will help to separate the stuck gunk from the unit.

For demineralization and removing vinegar from the system, you will need to flush the whole system for about 45 minutes.

Flushing the System:

In traditional tank-style water heaters, limescale deposits gather inside of the tank leading to massive explosions.

Luckily in the case of tankless water heaters, there is no chance of such explosion but there is a need to flush these sediments out of the system if you don’t want to compromise the functioning of your water heater.

Flushing not only helps to enhance the efficiency of your water heater but will also save you from many other troubles.

For this process, you need to install an isolation valve. If your unit lacks that valve, ask a plumber to install one for you. Shut off the valve to cut off the supply of water or gas to avoid any kind of hazard.

Then attach hoses to each isolation valve. Connect the small pump to the cold end of a water hose and then put both ends of a hot water hose and circulation pump inlet inside a bucket of 5 gallons filled with water.

Turn on the pump and allow water to circulate through it for an hour. The pressure or force produced by water will clean the system and help you to get rid of limescale build-up.

Cleaning Water Filter:


Never forget the water filter while doing some maintenance of your water heater. There is a feature in the screen of most of the tankless water heaters that prevent from any sediment coming in. There will be a need to clean those sediments time by time for proper efficiency.

If there is a build-up of those sediments, it can harm the functioning of your water heater. For removing a filter, turn off the water supply, remove the filter and then clean it properly.

A cloth or warm soapy water can be used for this purpose. If it is being difficult for you to find the water filter, check out the manual to find its location.

Cleaning Air Filter:

There is an air filter present inside that also requires cleaning. For its cleaning, first, you have to remove the air filter from the heater. Then get a soft brush and use water and soap solution to clean it.

Rinse the solution from the air filter and let it dry for some time before putting it back.

Clearing The Tank:

Cleaning the outside of the tank is also important to wipe out debris or dirt. Turn off the water supply; wipe down the tank all around. Wipe it thoroughly so there will be no dust and debris left to cause damage in the future by getting into the water heater.

Exterior Maintenance Also Matters

We find it important to mention the significance of exterior maintenance too. It does not require any trick or extraordinary supplies. You can do it easily within minutes by yourself.

Wipe down the cover with the help of a non-abrasive cleaner and a soft piece of cloth. It will help to avoid dust and rust buildup.

Check out the pipes. During winter it is important to inspect pipes so you can avoid frozen water inside pipes. It is also necessary to check for insulation.

Make sure to have a pressure relief valve in your tankless water heater.

This whole maintenance of the exterior will take 20 minutes or less but it will be worth it.

How often should you do its maintenance?

To keep up the efficiency of your tankless water heater you will need to do its maintenance at least once per year. While other tasks such as exterior cleaning can be done more often if the area is dusty.

If you are living in an area of hard water you may need to do its cleaning twice a year. Routine maintenance will extend the lifeline of your tankless water heater for more than 20 years without compromising its functioning. This statement is backed by experts.


Electric Tankless Model of 2022

About Fareed Nawaz

Aqua macho was started by Fareed, a renewable energy and clean environment geek who completed his degree in energy and environment in 2017. He has worked in EPA, water heater installation, and water treatment companies for 2 years before starting this website.

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