How to Complete Tankless Preventative Maintenance Tasks

Tankless Water Heater Preventative Maintenance

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 unit can operate for up to 25 years.

​A little preventative maintenance can go a long ways in saving you money and future headaches. Installing a sediment filter can not only provide you peace of mind, but also protect your tankless water heater from poor water quality.

Although flushing your unit regularly is critically important to getting the most from your tankless, there are a few other tasks that should be performed frequently. The homeowner can perform many of these tasks, but we strongly recommend hiring a professional to inspect your unit annually.

  • CONSIDER: Hiring a professional to walk you thru the preventative maintenance tasks 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.

Preventative Maintenance for Your Tankless Water Heater

  • WARNING: Use caution when working with your tankless water heater. The water within the system can be VERY hot, especially if the unit was just operating.
  • WARNING: Turn off the electrical power when you are working on the unit. This should be done by either unplugging the unit or turning off the circuit breaker. 
  • Always check your owners manual for specific instructions regarding your unit. 
Electric Tankless Water Heater

A large part of an electric tankless water heater's preventative maintenance is an annual flush to remove limescale build-up. However, beyond flushing, they need very little additional maintenance. Some manufacturers, like Navien, use an air filter that requires regular cleaning, so as always, you should check your owner's manual for details. 

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. 

Gas Tankless Water Heater

​Keeping your 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 need general cleaning, but depending upon where the unit is installed, it 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.​

Necessary Supplies



General Cleaning

  1. Turn OFF the electrical power and allow the tankless water heater to cool. The water trapped inside could be very hot. 
  2. Turn OFF the Gas Supply.
  3. Close the Hot and Cold Water Shut-off Valves
  4. Remove the front panel and double check that no electricity is reaching the unit by using a non-contact voltage tester.
  5. Remove and clean the Cold Water Inlet Filter on the cold water line. If your unit has an outlet filter on the hot water line, remove and clean it as well. Click HERE for instructions.
  6. 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.
  7. Wipe the cabinet with a soft, dry cloth.

​Annual Checks

Vents - 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.

Motor - ​Check your owners manual for lubrication requirements. Most manufacturers install permanently lubricated motors into their units. If this is the case with yours, it shouldn't require any lubrication.

It's critical to check the fan and motor to ensure that they are free of dirt and dust. We recommend cleaning it annually with pressurized/compressed air. Depending on where your unit is installed and the amount of dirt and dust it is 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 could be very hot.

  • WARNING: The water released during this test may be extremely hot. Potentially scalding hot water will be under pressure and severe burns may occur.
  • Precautions must be taken to ensure that the discharged water has an appropriate place to flow, and does 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 unit has been serviced. A licensed professional will perform this task for you when they complete their annual maintenance. ​

Look thru 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 color without any yellow or orange. Check your owners manual for specific information. 

Other Considerations

​Snow Accumulation - If you live in an area that is prone to snow, it's important 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 unit will not properly function. 

CLICK HERE to check out our more extensive post on cold weather precautions for tankless water heaters. ​

​Coastal Areas - If you live in a coastal area you may need to perform additional maintenance on your unit. Coastal regions are prone to airborne ocean salt, which can be very corrosive.​