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Descaling Tankless Water Heaters: the How’s and Why’s

Everything that uses water collects scale, or calcium and lime build-up, including your tankless water heater. To function properly, it needs regular descaling. However, it’s a bit more challenging to flush and descale a tankless water heater than a tank water heater. We’ll explain why and how you can descale your water heater.

Why Do Tankless Water Heaters Need to be Descaled?

Scale collects inside your tankless water heater slower than in a tank. However, the calcium-build up still gets in the way of the tankless water heater’s functioning. The build-up clogs up the heating elements, making them less effective.

This build-up will cause your heater to use more and more energy over time to get your water up to temperature. If you let your tankless water heater go a long time without maintenance, the build-up can also restrict the flow of water, so you receive less hot water than normal.

Eventually, the build-up may erode the walls of your tankless water heater to the point it needs to be replaced.

In Concord, water is relatively soft, so you don’t have to have your tankless water heater descaled as often as homeowners in other states. However, you will still have to get your heater descaled regularly.

Many water heaters have alerts that let you know when the scale is starting to impact their performance. Or, you can ask you plumber how often homes in your area typically need their tankless water heaters maintained.

How to Descale Your Tankless Water Heater

Your tankless water heaters were installed in your walls, where they have access to the pipe and water you want to be heated up. In order to access the tankless water heater, you may need a plumber’s help, both to locate it and open up the wall.

In fact, it’s best to get a plumber’s help for this process, as it involves disconnecting the tankless water heater and reconnecting it.

In order to descale your tankless water heater, your plumber will:

  • Turn off the heater and disconnect its power source
  • Close the valves that allow cold water to enter the heater
  • Close the valve that connects the tankless water heater to the home
  • Open the purge valves to relieve pressure, taking care to keep the rubber washers
  • Attach hosing lines that work with the specific tankless water heater model
  • Open purge valves again
  • Run vinegar through the tankless water heater to remove the scale
  • Flush and drain according to the manufacturer’s instructions for 45 minutes
  • Close the purge valves, disconnect the hose
  • Reconnect your heater to the house’s water system
  • Turn the power back on and restart the tankless water heater

Why Choose a Professional for Tankless Water Heater Descaling?

Your tankless water heater touches all of the drinking water in your home. You may accidentally do something to jeopardize your water if you descale your tankless water heater incorrectly. Common problems include using harsh chemicals to attempt to descale the heater (which you then drink) or leaving a valve closed that should be open.

It’s always better to trust a professional to descale your tankless water heater so that you know it has been done properly.