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How to: Draining and Flushing
Updated over a week ago

Draining and Flushing of Eccotemp Tankless Water Heater Systems

WARNING: Hot water may be present in the system during this process. The risk is significantly higher if the heater has just been in use prior to the cleaning operation. Always use extreme caution when servicing a tankless water heater. Hot water can cause injury, damage to property or even death.

Note: Vinegar is the recommended cleaning agent, as no chemicals should be used because its likely someone will drink from water that passes through this unit and hazardous chemicals may remain inside a tankless water heater system after many flushes and rinses.

Below are instructions for the use of service valves for the draining and flushing of a Eccotemp tankless water heater.

  1. Disconnect the electrical power from the water heater. Close the main water valve handles on the cold water valve and the hot water valve by rotating each until they are perpendicular with the respective valve body. This shuts off the incoming cold water to the water heater and isolates the water heater from the hot water pipes going into the plumbing system.

  2. On the cold water valve, there is a purge valve with a small T-Handle. This is used as the flushing inlet and the opposite purge valve on the hot water side is used for the flushing outlet or return drain. Be certain that the outlet hot water purge port is closed (perpendicular to the purge port valve body) before removing the purge port valve cap.

  3. Slowly open the drain caps on each purge port valve. Be sure to inspect the cap to ensure that the rubber washer sealing disc stays in each respective cap.

  4. Continue with the manufacturer's recommended procedure for attachment of the lines and for specific draining and flushing instructions.To open the purge port valves, the T-Handles on the port outlet pipes are rotated so that they are parallel to each purge port valve body.

  5. When flushing is complete and before the lines are removed, verify that the purge port valves are closed. Remove the lines and reinstall the purge port valve caps, ensuring that the rubber washer is in the cap, and tighten. (NOTE: To prevent damage to the rubber sealing discs (washers), do not over tighten these caps.)

  6. Re-start-up & return to normal operation

  7. Before turning on the supply water to the heater, make sure that the main valve handles on both the hot & cold valves are closed (perpendicular to the main valve bodies). Also ensure that the purge port valve caps are tightened down and that the valves are in the closed position (T-Handle perpendicular to the purge port valve body). WARNING: NEVER RELY ON THE PURGE CAP TO STOP THE WATER FLOW

  8. For water heater start-up, refer to the water heater owners' manual.

  9. During normal operation, the main water valves are open when the main valve handle is parallel with the main valve body and closed when the main valve handle is perpendicular to the main valve body. To return the heater to operation, rotate the main water flow handles to a parallel position in alignment with the main valve body. At this time, water will begin entering the heater. Slowly open a hot water tap in the sink and allow the air to pass through the system until the water no longer is burping air. With the hot water tap opened and running, wait for several seconds to be sure that the lines are cleared of air. At this point, you should run the hot water tap for a minute or two to clear any residual air and cleaning agent from the system.

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