Essential Tankless Water Heater Maintenance: A Complete Guide

Tankless water heaters have become increasingly popular due to their energy efficiency and endless hot water supply. However, like any appliance, they require regular maintenance to perform at their best. This guide will walk you through everything you need to know about keeping your tankless water heater in top condition.

3D animated plumber character performing tankless water heater maintenance
Your friendly maintenance guide assistant!

Why Maintenance Matters

Regular maintenance of your tankless water heater is crucial for several reasons:

  • Extended lifespan – Proper care can help your unit last 20+ years
  • Optimal efficiency – Prevents energy waste and keeps utility bills low
  • Consistent performance – Ensures reliable hot water delivery
  • Warranty protection – Many manufacturers require regular maintenance to honor warranties

Annual Maintenance Tasks

1. Descaling/Flushing the System

Mineral buildup (scale) is the biggest enemy of tankless water heaters, especially in areas with hard water. Flushing your system annually removes these deposits.

What you’ll need:

  • Two hoses
  • A submersible pump
  • A 5-gallon bucket
  • White vinegar or commercial descaling solution

Steps:

  1. Turn off the power and gas supply to the unit
  2. Close the hot and cold water shut-off valves
  3. Connect hoses to the service valves
  4. Fill the bucket with vinegar and place the pump inside
  5. Circulate the vinegar through the system for 45-60 minutes
  6. Flush with clean water to remove any remaining vinegar
  7. Restore normal operation

2. Cleaning the Air Filter

Gas tankless water heaters have air filters that prevent debris from entering the combustion chamber. Check and clean these filters every few months.

  • Locate the filter (usually at the bottom of the unit)
  • Remove and rinse with water
  • Allow to dry completely before reinstalling

3. Inspecting the Water Filter

Many tankless units have an inline water filter that traps sediment. Clean this filter regularly to maintain proper water flow.

4. Checking the Venting System

For gas units, inspect the venting system for:

  • Blockages or obstructions
  • Corrosion or damage
  • Proper connections and seals
  • Bird nests or debris at the exterior vent cap

Signs Your Tankless Water Heater Needs Attention

Watch for these warning signs that indicate maintenance is overdue:

  • Fluctuating water temperature – Water that goes hot and cold
  • Reduced water flow – Lower pressure than normal
  • Error codes – Check your manual for specific meanings
  • Strange noises – Clicking, humming, or rumbling sounds
  • Discolored water – Rusty or cloudy water output

Professional vs. DIY Maintenance

While many maintenance tasks can be done yourself, consider hiring a professional for:

  • Annual comprehensive inspections
  • Gas line and connection checks
  • Complex repairs or error codes
  • Warranty-required service

Tips for Extending Your Unit’s Life

  • Install a water softener if you have hard water
  • Use a sediment filter on the incoming water line
  • Avoid overworking the unit by staggering hot water usage
  • Keep the area around the unit clear for proper ventilation
  • Address issues promptly before they become major problems

Conclusion

Regular maintenance is the key to getting the most out of your tankless water heater investment. By following this guide and staying on top of annual flushing and filter cleaning, you’ll enjoy reliable hot water for years to come. If you’re uncomfortable performing any of these tasks yourself, don’t hesitate to call a licensed plumber or HVAC technician.

Have questions about tankless water heater maintenance? Leave a comment below or contact us for personalized advice!