Rinnai Flush Routine - Tankless Maintenance DIY

Introduction

This tutorial outlines a DIY maintenance routine for tankless water heaters, specifically focusing on flushing the unit to remove scale buildup. Regular maintenance ensures your tankless water heater lasts over 20 years, and this process is applicable to various brands, including Rinnai, Takagi, and Rheem.

Step 1: Prepare for Maintenance

• Power Off: Unplug the tankless water heater to ensure safety.
• Turn Off Gas: Locate the gas line and turn it off. The valve should be perpendicular to the line when off.
• Shut Off Water Supply: Turn off the water supply to the unit by closing the valves connected to the hot and cold water lines.

Step 2: Check for Flush Valves

• Inspect for Flush Valves: Ensure your unit has flush valves installed. If not, you will need to have them added by a plumber. This is crucial for performing the flush.

Step 3: Set Up the Flush Kit

• Connect Hoses:
  • Attach one hose to the hot water flush valve (where water exits).
  • Connect the other hose to the cold water valve (where water enters).
• Connect to Pump:
  • Attach the cold side hose to a submersible pump.
  • Place the pump inside a 5-gallon bucket filled with water and Flow-Aid descaling solution. For every gallon of water, add one quart of the solution.

Step 4: Start the Flushing Process

• Create a Loop:
  • Run the hose from the hot side back into the tank to create a closed loop.
• Open Flush Valves: Open the flush valves to allow the solution to flow through the system.
• Power the Pump: Plug in the pump and let it run for 30 to 45 minutes. For effective descaling, aim for the full 45 minutes.

Step 5: Flush with Fresh Water

• Disconnect the Pump: After 45 minutes, unplug the pump.
• Flush with Cold Water:
  • Close the isolation valve on the cold water side and disconnect the hose.
  • Turn on the cold water supply to flush fresh water through the system for about 2 minutes. This helps wash away any loosened debris.

Step 6: Clean the Filter

• Access the Filter: Locate the filter at the inlet of the unit. It may require a tool to remove.
• Clean the Filter: Rinse the filter under running water or blow it out to remove any collected debris.
• Reinstall the Filter: Once cleaned, securely place the filter back into the unit.

Step 7: Restore Power and Water Supply

• Reconnect Hoses: Ensure all hoses are properly disconnected and stored.
• Open Isolation Valves: Turn on the cold and hot water supply valves.
• Turn On Gas: Open the gas valve to the unit.
• Plug In the Unit: Reconnect the power to the heater.

Conclusion

Regular flushing of your tankless water heater every 12 to 18 months is crucial for maintaining efficiency and prolonging its lifespan. Following these steps will help you perform this maintenance task easily. For more information or to purchase a flushing kit, check the links provided in the video description. Happy maintenance!