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How To Maintain Your Tankless Water Heater For Optimal Performance

Tankless water heaters, also known as on-demand water heaters, offer significant advantages in terms of energy efficiency, space savings, and continuous hot water supply. However, to ensure they operate at peak performance and have a long lifespan, regular maintenance is essential. This comprehensive guide covers everything you need to know about maintaining your tankless water heater, including the benefits of regular maintenance, common maintenance tasks, troubleshooting tips, and best practices.

Tankless water heaters heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit, where either a gas burner or an electric element heats the water. This results in a constant supply of hot water, as long as the demand does not exceed the unit’s capacity. Tankless water heaters are known for their high energy efficiency, long lifespan, and compact size.

Benefits Of Regular Maintenance

Regular maintenance of your tankless water heater offers several benefits:

  • Enhanced Efficiency: Regular cleaning and descaling prevent mineral buildup, ensuring the unit operates efficiently and reduces energy consumption.
  • Extended Lifespan: Proper maintenance can significantly extend the life of your tankless water heater, protecting your investment.
  • Improved Performance: Regularly maintained units provide consistent hot water supply without temperature fluctuations.
  • Reduced Repair Costs: Early detection and resolution of issues can prevent costly repairs and potential system failures.
  • Safety: Maintenance ensures all components are functioning correctly, reducing the risk of malfunctions that could lead to safety hazards.

Common Maintenance Tasks

Flushing The System

Mineral buildup, especially in areas with hard water, can clog the heat exchanger and reduce efficiency. Flushing the system with a descaling solution removes these deposits.

Cleaning The Inlet Filter

The inlet filter traps debris and sediments from entering the unit. Regular cleaning ensures optimal water flow and prevents damage to internal components.

Inspecting And Cleaning The Venting System

For gas-powered units, the venting system must be inspected and cleaned to ensure proper exhaust of combustion gasses and to prevent blockages that could lead to dangerous carbon monoxide buildup.

Checking The Pressure Relief Valve

The pressure relief valve prevents excessive pressure buildup in the system. Regular checks ensure it operates correctly and prevents potential hazards.

Inspecting The Burner Assembly

For gas-powered units, the burner assembly should be inspected and cleaned to ensure efficient combustion and to prevent ignition issues.

Monitoring Water Quality

Using a water softener or filter can help reduce mineral buildup and improve the performance and lifespan of your tankless water heater.

Step-By-Step Maintenance Guide

Tools And Materials Needed

  • White vinegar or a commercial descaling solution
  • Bucket
  • Hose
  • Screwdriver
  • Soft brush
  • Cloth
  • Water softener (optional)
  • Gloves and safety goggles

Safety Precautions

  • Turn off the power supply (electric or gas) before performing any maintenance.
  • Allow the unit to cool down before handling.
  • Wear gloves and safety goggles to protect yourself from hot water and chemicals.

Detailed Maintenance Procedures

Flushing The System

  • Turn Off The Power: Turn off the electrical power to the unit or close the gas valve for gas-powered units.
  • Shut Off The Water Supply: Close the water valves to prevent water from entering the unit.
  • Connect Hoses: Connect hoses to the cold water inlet and hot water outlet valves.
  • Prepare The Descaling Solution: Mix white vinegar or a commercial descaling solution with water in a bucket.
  • Circulate The Solution: Use a submersible pump to circulate the solution through the unit for 45 minutes to an hour.
  • Flush With Clean Water: Disconnect the hoses and flush the system with clean water to remove any remaining solution.
  • Reconnect And Turn On: Reconnect the water supply, turn on the power, and restart the unit.

Cleaning The Inlet Filter

  • Turn Off The Power And Water Supply: Ensure the unit is off and the water supply is closed.
  • Locate The Inlet Filter: The filter is usually located at the cold water inlet.
  • Remove And Clean: Unscrew the filter, rinse it under running water, and use a soft brush to remove any debris.
  • Reinstall: Place the cleaned filter back into its position and secure it.

Inspecting And Cleaning The Venting System

  • Turn Off The Power And Gas Supply: Ensure safety by turning off all power and gas supply to the unit.
  • Inspect The Venting: Check for blockages, leaks, or damage in the venting system.
  • Clean The Venting: Use a brush or vacuum to remove any debris or obstructions.
  • Reassemble: Ensure all components are properly secured and reassemble the venting system.

Checking The Pressure Relief Valve

  • Turn Off The Power And Water Supply: Safety first.
  • Locate The Valve: The pressure relief valve is typically on the top or side of the unit.
  • Test The Valve: Lift the valve handle to ensure it opens and closes properly. If water flows out, the valve is working correctly.
  • Replace If Necessary: If the valve does not operate correctly, replace it.

Inspecting The Burner Assembly

  • Turn Off The Power And Gas Supply: Ensure the unit is safe to handle.
  • Access The Burner Assembly: Remove the cover to access the burner.
  • Inspect And Clean: Check for soot, debris, or corrosion. Use a soft brush to clean the burner.
  • Reassemble: Securely reattach the cover and ensure all connections are tight.

Monitoring Water Quality

  • Install A Water Softener: If you live in an area with hard water, consider installing a water softener to reduce mineral buildup.
  • Regularly Check Water Quality: Test the water quality and adjust the softener settings as needed.

Troubleshooting Common Issues

  • Check Power Supply: Ensure the unit is receiving power.
  • Inspect The Thermostat: Verify the thermostat settings and adjust if necessary.
  • Clean The Filter: A clogged filter can restrict water flow.
  • Examine The Heat Exchanger: Mineral buildup can cause the unit to overheat and shut down.

Fluctuating Water Temperature

  • Inspect The Flow Sensor: A malfunctioning flow sensor can cause temperature fluctuations.
  • Check For Mineral Buildup: Descale the unit to ensure efficient operation.
  • Verify Water Flow Rate: Ensure the unit’s capacity matches the household’s hot water demand.

Strange Noises

  • Air In The System: Bleed the system to remove any trapped air.
  • Mineral Buildup: Descale the unit to remove deposits that can cause noise.
  • Loose Components: Tighten any loose parts to eliminate vibrations and noise.

Error Codes

  • Consult The Manual: Refer to the unit’s manual to understand the specific error code.
  • Reset The Unit: Sometimes, resetting the unit can resolve minor issues.
  • Call A Professional: If the error persists, contact a professional technician for assistance.

Best Practices For Optimal Performance

Scheduling Regular Maintenance

  • Annual Maintenance: Schedule a professional maintenance check at least once a year.
  • DIY Checks: Perform regular DIY checks and maintenance tasks every few months.

Using A Water Softener

  • Install A Softener: Reduce mineral buildup by installing a water softener.
  • Regularly Check: Monitor the softener’s performance and adjust settings as needed.

Monitoring Usage And Adjusting Settings

  • Optimize Settings: Adjust the temperature and flow rate settings to match your household’s needs.
  • Monitor Usage: Keep track of your hot water usage to identify any unusual patterns or issues.

Keeping The Unit And Surrounding Area Clean

  • Clean The Unit: Regularly wipe down the exterior of the unit to prevent dust buildup.
  • Clear The Surrounding Area: Ensure the area around the unit is free of clutter and debris for proper ventilation and access.


Maintaining your tankless water heater is crucial for ensuring optimal performance, energy efficiency, and a long lifespan. Regular maintenance tasks such as flushing the system, cleaning the inlet filter, inspecting the venting system, checking the pressure relief valve, and monitoring water quality can prevent common issues and improve the overall functionality of your unit. By following the detailed maintenance procedures and best practices outlined in this guide, you can enjoy continuous, efficient hot water supply while protecting your investment. If you encounter persistent issues or need assistance, don’t hesitate to consult a professional technician for expert advice and service.

Experience Excellence In Tankless Water Heaters With Garcia Plumbing And Home Restoration!

We understand the importance of having a reliable and efficient water heating system in your home. Our dedicated team of licensed experts leads the way in providing exceptional tankless water heater solutions that ensure both energy efficiency and consistent performance.

Beyond just water heater installations and repairs, Garcia Plumbing and Home Restoration offers comprehensive home maintenance solutions. Our reputation in Contra Costa County is built on unwavering quality, unmatched expertise, and the trust of numerous satisfied clients. Don’t compromise when it comes to your home’s comfort and energy efficiency. Contact us today for outstanding tankless water heater services and embrace a worry-free plumbing future!

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