Flush tankless water heater

Hi everyone, welcome back to Happi Plumbing Channel.

This time we specifically filmed a clear and comprehensive video to show everyone how to DIY flush and descale a tankless water heater. Doing it yourself can save you hundreds of dollars!

This is the connection diagram for the flushing process.

https://video.wixstatic.com/video/4c049c_82dfccd9223c4bf0b7019f48c18d49aa/480p/mp4/file.mp4

Step-by-Step Procedure

1. Turn off power to the tankless water heater.

2. Close the cold and hot isolation valves (V1 and V2), then remove the service port caps (service caps).

3. Pour 32 fl oz of descaling solution into a bucket containing 1 gallon of clean water.

4. Connect a hose to a utility pump, and connect the other end of the hose to the cold-water service valve (V3). Place the pump inside the bucket.

5. Connect a second hose to the hot-water service valve (V4), and place the other end back into the bucket.

6. Plug the pump into a properly grounded electrical outlet.

7. Allow the pump to circulate the descaling solution through the water heater continuously for 30–45 minutes. When finished, unplug the pump.

8. Close the cold-water service valve (V3) and reinstall the service port cap.

9. Disconnect the hose from the pump and remove the pump from the bucket. Properly dispose of the used descaling solution.

10. Flush the water heater with clean water for 3–5 minutes, or until the discharge water runs completely clear:

11. Open the cold-water isolation valve (V1).

12. Allow water to flow out through the hot-water service valve (V4) into a drain or bucket.

13. If using a bucket, empty it as needed during the flushing process.

14. Close the hot-water service valve (V4).

15. Disconnect the hose.

16. Reinstall the service port cap.

17. Open the hot-water isolation valve (V2).

18. Restore power to the water heater and return it to normal operation.

Note: Always consult your water heater manufacturer's maintenance instructions before performing any descaling or flushing procedure, as valve configurations and recommended cleaning solutions may vary by model.

Now you should be able to flush and descale your tankless water heater yourself.