How to Clean a Tankless Water Heater

Water heaters make our lives pleasurable in their own way. However, over time, mineral and corrosion can build up inside the heating chambers. When that happens, you will be glad you learned how to clean a tankless water heater.

clean a tankless water heater


If you already have that issue, well, it’s your lucky day! Today, Vacuum Cleaners Advisor will show you the method professionals use to maintain and clean a tankless water heater.

By the time you’re done, you will be confident to go down the basement (or wherever yours is installed) and deal with the problem.

Without further ado, let’s get on with it.



Steps to Clean a Tankless Water Heater

  1. Turn off the power supply. You can either do that by shutting off the gas supply to the heater or you turn off the circuit breaker supplying power.
  2. Turn off all water valves attached to the tankless water heater. There is the blue valve for cold water, a red one for hot water, and then the main valve that flows water into your home. Turn the ‘T’ handle (the shut-off valve) to align with the purge cap to turn them off.
  3. Take off the purge port caps from the valves. The aim of this procedure is to release any pressure in the valves. So, be sure to turn on the service valve (the smaller handle) slowly. You should have a bucket by the cap to collect the water and prevent any hot water remaining in the pipe from splashing on you.
  4. Insert a hose in the valves. Some tankless water heaters come with hoses for this procedure. However, if yours doesn’t, you might have to purchase them from a hardware store (a washing machine hose will work perfectly). The other ends of the hoses should lead to a bucket. You might have to consult the user manual for your tankless water heater for the specific method of flushing water through the valves.
  • In a general case, connect the end of the hose in the cold valve to a utility pump and put the pump in the bucket while the end of the hose from the hot valve just sits in the bucket. WAYNE WWB WaterBUG Submersible Pump with Multi-Flo Technology
  1. Pour undiluted white vinegar into the bucket. You will need about a gallon or two of white vinegar for this process. This Harris vinegar is a potent option. Using any other cleaning agent is a no-no. You don’t want any chemical near your source of water.
  2. Restore power to the tankless water heater and turn it on. This will cycle the vinegar in and out of the heating chamber. Let this process continue for an hour. Remember to turn it off when the time is up.
  3. Let all the liquid from the heating chamber drain out and disconnect the hoses. When you come back, you will notice the vinegar has turned murky. That’s a sign of a job well done. Disconnect the hose from the utility pump too.
  4. Close the service valves and replace the purge port caps.
  5. Turn back on the water valves. It is best practice to start with the cold water valve. An indicator on the tankless water heater will let you know when it is full. Then, turn on the hot water valve.
  6. Finally, turn on the power supply and put on the tankless water heater. After the cleaning process, it is time to reap the benefit of all our effort. Turn on your tap indoor and notice the difference. You will get a smell of the vinegar initially but that will pass shortly. Now, you’re ready to use hot water like nothing happened.






This is all that is involved in cleaning a tankless water heater. If you find this information useful, kindly share with friends and loved ones. They will surely thank you for it. For more cleaning pro tips and vacuum cleaner reviews, kindly explore our site. Thank you for your time.