How to Remove Lime Scale from a Tankless Water Heater

Lime scale is a white substance that builds up on items exposed to hard water. Over the course of time lime scale can damage a tankless water heater and lessen its efficiency. A tankless water heater, also known as a demand water heater, provides hot water as necessary. Tankless water heaters can be electric or gas powered.

Things You'll Need

• Bucket
• Pipe wrench
• Hoses
• Submersible pump
• White vinegar

Instructions

1. Turn off the power supply to the water heater. Allow the water heater to cool to room temperature before proceeding.

2. Shut off the water inlet and outlet valves. The shut-off valves are generally located near the hoses.

3. Place a large bucket or container under the water heater to catch excess water.

4. Disconnect the inlet and outlet hoses from the water heater with an adjustable pipe wrench.

5. Connect two hoses long enough to run from the base of the bucket to the water heater. Tighten the fittings with the pipe wrench and open the inlet and outlet valves. Pour excess water out of the bucket.

6. Hook up the inlet hose to a submersible pump and place the pump into a bucket along with the outlet hose.

7. Fill the bucket with white vinegar.

8. Turn on the submersible pump. Allow the pump to run white vinegar through the water heater and out through the outlet hose back into the bucket. Allow the pump to push vinegar through the water heater for 30 to 45 minutes. If during the flushing process the vinegar turns white or cloudy, stop the pump, discard the vinegar and replace with new vinegar.

9. Turn off the pump and discard the white vinegar. Fill the bucket with plain water. Place the pump into the water and turn it back on. Allow the pump to push clean water through to remove any residual vinegar taste from the water heater. Allow the pump to run for 15 to 20 minutes.

10. Turn the pump off and close the inlet and outlet valves. Disconnect the hoses with a pipe wrench. Reconnect the original hoses and tighten the fittings. Open the inlet and outlet valves. Restore the power to the water heater.

Tips & Warnings

• Clean your tankless water heater regularly to avoid lime scale build up. The degree of hardness of your water determines the frequency of cleaning.

References

• "Grandpa's 5001 Handyman Secrets"; Dr. Myles H. Bader; 2006
• "Reader's Digest Complete Do-It-Yourself Manual"; Family Handyman Magazine Editors; 2005