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Tankless Water Heater Preventative Maintenance


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Knowing the in's and out's of preventative maintenance for your tankless water can make a big difference in keeping your unit running efficiently. With the proper installation and the completion of both the annual and preventative maintenance tasks, a tankless water heater can have a service life of up to 25 years.

With a service life of up to a quarter-of-a-century, it's clear to see that performing a few preventative maintenance tasks each year can save you huge amounts of money and future headaches. We also highly recommend installing a sediment filter to help protect your tankless water heater from poor water quality.

Tankless Water Heater Preventative Maintenance

How to Keep Your Tankless Water Heater in Peak Condition

Whether you own a gas or electric tankless water heater, the single most important preventative maintenance task you can do is to flush the unit on a regular basis.

We cover how to flush your tankless heater HERE with step-by-step directions. With that said, there are a few other important preventative tasks that should be performed, which is the subject of this article.

Although, the homeowner can perform many of these tasks, we strongly recommend hiring a professional to inspect your tankless water heater once a year.

You may also want to consider hiring a professional to walk you through the preventative maintenance tasks for the first time. You'll be able to observe, ask questions and take notes. The next time you need to perform the tasks, you'll know exactly what to do.

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Before working on your tankless water heater, be sure to turn off the electrical power by either unplugging the unit or turning off the circuit breaker. In addition, it's important to remember that the water within the tankless system can be very hot, especially if the heater was just operating.

As always, check your owners manual for specific instructions regarding your tankless water heater.

Electric Current

Electric Tankless Preventative Maintenance

A large part of preventative maintenance for an electric tankless water heater is the annual flush. This flush removes the limescale build-up and helps the heater operate as efficiently as possible. However, beyond flushing, electric heaters require very little additional maintenance.

Some manufacturers, such as Navien, use an air filter that requires regular cleaning. Checking your owners manual will alert you to any specific tasks that are recommended for your tankless.

Electric units run cleaner in general simply because there are no byproducts, such as soot, from combustion. Since the unit isn't "burning" the fuel, combustion is not needed to heat the water.

Electric tankless water heaters have an entirely different design than their gas fueled cousins, but without the need for combustion to operate, they run much cleaner. Cleaner units equate to less maintenance.

> > Learn How to Flush Your Tankless Water Heater HERE < <

Hands holding a gas burner

Gas Tankless Preventative Maintenance

Keeping your gas tankless water heater clean is an important, and often overlooked, part of preventative maintenance.

It's imperative that the burners, circulating air passageways and control compartments are clean and free of dust and debris.

All tankless water heaters require general cleaning, however, depending upon where the system is installed, yours may require more frequent cleaning due to an increase of dust build-up.

The process is simple and can be done with other maintenance tasks or as a stand alone procedure.

Here's what to do:

  • Turn OFF the electrical power and allow the tankless water heater to cool. The water trapped inside could be very hot. 
  • Turn OFF the gas supply.
  • Close the Hot and Cold Water Shut-off Valves.
  • Remove the front panel and double check that no electricity is reaching the heater by using a non-contact voltage tester
  • Remove and clean the Cold Water Inlet Filter on the cold water line. If your tankless system has an outlet filter on the hot water line, remove and clean it as well. Click HERE for instructions.
  • Use pressurized air/compressed air to clear any dust from the main burner, fan blades, and heat exchanger. Never use a wet cloth or cleaners on the burner. Volatile substances may ignite!
  • Wipe the cabinet with a soft, dry cloth.

> > Learn How to Flush Your Tankless Water Heater HERE < <

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Annual Preventative Checks

There are several checks that you should perform on an annual basis. As we mentioned above, you may want to consider hiring a professional to show you what to look for and how to solve the issues you may run across. 


Every year you should check your vent system to ensure that there are no blockages or damage. If you find any issues with your vent, you should contact a licensed professional to perform the repairs.


Check your owners manual for lubrication requirements. Most manufacturers install permanently lubricated motors into their tankless systems. If this it the case with yours, it should not require lubrication.

Fan and Motor

It's critical to check the fan and motor to ensure that they're free of dirt and dust.

We recommend cleaning it annually with pressurized/compressed air.

Depending on where your tankless system is installed and the amount of dirt and dust it's exposed to, you may need to clean these parts more frequently. 

Pressure Relief Valve

The pressure relief valve should be manually tested every year. We highly recommend hiring a licensed professional to perform this task as the water released will be under pressure and could be extremely hot and potentially scalding.

Severe burns may occur. It will be necessary to take precautions to ensure that the discharged water has an appropriate place to flow, and that it will not come in contact with your body or property, as damage and harm may occur.

Flame Inspection

The flame should be visually checked to verify proper operation. This task should be done after the tankless unit has be serviced.

A licensed professional will visually inspect the flame for you when they complete their annual maintenance. However, you can do it yourself by looking through the view ports to check that the flame is stable and evenly covering the entire surface of the burner.

The flame should be a clear, blue in color and without any yellow or orange. 

> > Learn How to Flush Your Tankless Water Heater HERE < <

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Special Considerations

If you live in an area that is prone to snow, it's critical to keep the area around the flue terminal free of snow and ice.

If the air intake or exhaust is blocked, or partially blocked by obstructions, including snow and ice, the tankless water heater will not properly function.

Read our detailed post on cold weather precautions for tankless water heaters HERE.

Homeowners who have a tankless system installed in a coastal area may need to perform additional maintenance. Coastal regions are prone to airborne ocean salt, which can be very corrosive.

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