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Keeping a Tankless Water Heater Efficient
Updated over a week ago

Credits to: Matt Risinger

The tankless water heater, also referred to as an on-demand water heater, offers homeowners the convenience of having hot water available whenever it is needed, without requiring a very heavy tank to hold water in storage and keep it hot. The compact size of these water heaters, along with their efficiency, are two primary reasons behind their popularity.

Removing lime scale from a tankless water heater

According to Speed Clean, an ongoing maintenance requirement is to make sure your heat exchange elements are free from scale buildup, usually lime scale. What looks like a light coating of scale buildup can have serious impacts on the efficiency of the system. If left unchecked, such buildup can cause longer burner cycles, leading to a strained system and a shorter lifespan.

Speed Clean writes: “As with most situations, limescale buildup will differ based on the quality of the water being used, location, use amount etc.”

Before starting a maintenance project, it is wise to obtain specific information from the manufacturer.

For those wanting to leave the greenest footprint, white vinegar is a greener cleaning option than chemical formulations.

Step-by-step Maintenance

  1. If available, carefully review manufacturer’s cleaning instructions.

  2. Turn off the power source.

  3. Remove the lid from the water heater (usually just with a couple of screws).

  4. Close off three water valves supplying the water heater.

  5. Slowly remove the purge port valve caps from the purge valves located on each of the cold and hot water valves. (Relieves any pressure that has built inside the valves and will prevent excess hot water from shooting out and coming into contact with your skin.)

  6. Attach hosing lines to each of the 3 valves. These are usually supplied by the manufacturer.

  7. Open the purge port valves, twisting them perpendicularly to the position of the cold and hot valves.

  8. Use 2.5 gallons (9.46 liters) of undiluted white vinegar to clean the tankless water heater.

  9. Flush and drain, following the directions provided by the manufacturer.

  10. Close the purge port valves by twisting the “T”-shaped handles after the flushing process is complete.

  11. Disconnect the hosing lines from each water valve.

  12. Replace the purge port valve caps onto the purge valves. Make sure everything is properly tightened.

  13. Find the filter (should be labeled), remove it by unscrewing it, and clean out the housing and inside screen of the filter by just running it under tap water in the sink. When done, replace the filter.

  14. Refer to manufacturer’s manual for exact instructions on safely restarting the water heater, including replacing the cover and affixing it with the screws you removed earlier.

  15. Slowly turn on the hot water tap in your sink so air passes through the pipe.

Top Tankless water heaters

As of this July, Bestreviews lists the top five tankless water heaters. This ranking includes natural gas and electric products (three systems are natural gas, two are electric), and provides readers with a pretty comprehensive perspective.

  1. Stiebel Eltron Tempra 24 Plus Electric Tankless Whole House Water Heater, 240 V, 24 kW

  2. Rinnai RL75iN Natural Gas Tankless Water Heater, 7.5 Gallons Per Minute

  3. Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas

  4. Ecosmart ECO 27 Electric Tankless Water Heater, 27 KW at 240 Volts with Patented Self Modulating Technology

  5. Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater

Remember, before starting any maintenance or cleaning work, make sure the power is turned off. Also, close and turn off the water valves.

Protect your Tankless water heater using a Descaler Solution.To purchase and to check for more of our Eccotemp Descaler Kit, please visit the link below or you may email us at [email protected] or call 1-866-356-1992 (Mon-Fri 9am-5pm PM EST):

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