How to Flush a Tankless Water Heater

If you have a tankless water heater, it is important to maintain it to keep it from clogging. Plumbers suggest flushing tankless water heaters annually to keep them at maximum performance. Anyone with some DIY experience can flush a tankless water heater without using chemicals. Here are tips to flush a tankless water heater.

Prepare to Work

For this project, you need:

  • work gloves
  • screwdriver
  • adjustable wrench
  • two six-feet long garden hoses
  • three buckets
  • old towels
  • three to five gallons of undiluted white vinegar
  • sump pump or pond pump

Shut off the main power to the house from the breaker box, Turning off the main house power supply is safer, since water heaters use more than one power source.

To ensure no current exists, detach the screws on the access panel. Touch the probe tip of the voltmeter to the wiring. No sound indicates no current is present.

For gas water heaters, switch the gas valve, which is located on the bottom of the unit over the burner compartment, to "PILOT". If you prefer, set the valve to "OFF", but you will have to relight the pilot. Let the water cool.

Attach the Hoses

Shut off the cold and hot water supplies to the water heater. Lay down old towels and set a bucket under the drain valves. Attach one end of the first to the cold water valve, and connect the other end of the hose to the sump pump or pond pump outlet.

Attach another hose to the hot water valve, and lay the other end in a bucket. Pour five gallons of vinegar in this bucket. Twist the garden hose couplers with the wrench.

Pump Water

Open the hot and cold water supplies. Place the pump in the bucket of vinegar.

Switch the pump on, and let it run for about forty-five minutes. The pump will circulate vinegar through the water heater.

Shut off the pump, and let the vinegar finish draining out of the hose. Shut off the cold water valve. Discard the vinegar, then lay the hose end back in the same bucket.

Close the hot water valve. Open the cold water valve; allowing remaining water to drain in the bucket. Turn off the valve, and remove the hose from the valves.

Close the hot water valve, and detach the filter screen on the inlets. Rinse sediment from the screen, and reattach it. Turn on both water valves, and open a tap for several minutes to remove air pressure. Reattach the hoses to the hot and cold valves, and relight the pilot or restore power.

Flushing the tankless hot water heater helps your system run smoothly. If the water heater still seems clogged, or you don't trust your skill, call a plumber.

About Me

what goes into adding a bathroom to your home?

Having a house that only has two bathrooms and three teenage girls reached a point where I thought I was going to lose my mind. In all seriousness, I thought I was going to go crazy listening to the girls battle over whose turn it was to shower or who used whose makeup. After several months of dealing with the insanity every single day, I finally talked my husband into hiring a plumber to run the plumbing we needed to install a third bathroom. Adding a bathroom was a lot of work, but it was worth it. Our blog will help you understand what goes into adding a bathroom to your home.