Descaling and Maintaining Your Tankless Hot Water Heater


Keeping your home’s tankless water clean is important for your and your family’s health, as your water heater comes into contact with all of the tap water in your home—the water you and your family drink, cook and clean with.

Over time, all water heaters will build up scale deposits that decrease their efficiency. Scale is a calcium and lime buildup. How quickly buildup forms in your tank depends on your specific area’s water hardness—if you do not know when the last time your water heater was cleaned, it might be time to have someone look at it. Or, you can even check and clean it yourself with some patience and the proper tools.

A benefit of a tankless water heater is that they collect scale buildup slower than a tank. That being said, just because you will need to clean it less often does not mean you can ignore it. The calcium buildup clogs the heating elements, hindering your heater’s functionality.

This buildup will cause your heater to use more energy and can, eventually, restrict your water flow, leaving you with less hot water than normal.

Regular maintenance is important so you do not have to replace your water heater more than normal. Read on for a few tips to help you descale your tankless water heater.

Descaling your tankless hot water heater does not have to be difficult. Your water heater is installed in your walls, so you may need one of our expert’s help to find your heater in the wall, as well as open the wall up.

Unless you feel comfortable disconnecting and reconnecting your water heater, it might be best to have one of our Armstrong team members assist you to ensure everything is completely shut off and disconnected beforehand so the job can be done properly.

Descaling Your Tankless Water Heater

  • Turn off the heater, and disconnect it from the power source
  • Close the valves that let cold water into the heater and that connect the heater to your home
  • Open the purge valves to relieve any pressure off the heater
  • Attach the hosing likes specific to your heater, and reopen the purge valves
  • Pour vinegar through your water heater to remove the scale, and then flush and drain according to your water heater’s manufacturer’s instructions
  • Close your purge valves, and disconnect the hose
  • Reconnect the heater back to your home’s water system
  • Turn your power back on and restart the tankless water heater

Scale buildup in your water heater is completely normal and nothing to be nervous about, as long as you are performing regular maintenance and either checking it yourself or having a professional check it annually. If you have any questions about your tankless hot water heater, would like advice on how to clean it, or want one of our team members to inspect it, feel free to reach out to us at (636) 538-5179, or fill out a form for more information.

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