Flush Hot Water Heater
Flushing Sediments

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How to flush hot water heater. Why flushing is important for your heater. Step by step instructions.

Sediment build-up inside the heater's tank results in decreasing efficiency and low performance is the number one reason why flushing should be done regularly - at least once a year. Flushing a water heater is easy DIY project that doesn't require any special skills or tools. 

You don't have to be an electrician or gas technician to flush the hot water heater. Just use the recommended tools, follow the guide and be careful when dealing with the hot water.

Why flushing is important

Flushing a water heater should be done regularly, per manufacturer's recommendations. Sediment deposits at the bottom of the heater's tank are the problem as it will lower the heater's efficiency and increase the cost of the heating. This is especially important with the gas heaters, as the formed deposits will be between the heat source (combustion chamber and gas burner) and water. Electric units will have deposits on the heating elements which also reduces the heat transfer.

Other symptoms of the sediment and lime build-up are the annoying noise and the clogged drain valve.

Most of the newer models, either from Rheem, AO Smith or Bradford White manufacturers utilize systems to reduce the deposits, but still regular flushing is recommended.


Step by step guide how to flush hot water heater

  • The most important step when flushing water heater, either gas or electric powered, is to turn the power OFF (gas and/or the circuit breaker).
  • Open the nearby hot water tap and leave it open for draining, until the temperature goes below 100 F.
  • Shut OFF the water supply to the heater.
  • Use the garden hose and attach one end to the drain valve located at the bottom of the unit and the other end to an open drain or outside the house.
  • Open the TPR valve at the top of the unit and drain valve at the bottom.
  • Once all the water is drained and sediments flushed away, close the drain valve and TPR valve. Flush hot water heater as much as needed to remove the sediments.
  • Open the nearby hot water tap and manual shut OFF valve for the cold water, to start filling the tank.
  • Once the steady stream of water is established from the faucet turn it OFF.
  • Resume power.
  • Sometimes it is needed to flush the hot water heater several times. During the flushing, you will see white particles coming out through the drain valve... this is normal. Flush hot water heater often, at least once or twice a year or based on the quality of the incoming water.

If you live in the area where water is very hard you might have to do the flushing more often. Installing a water softener is a good idea to prevent mineral build-up, while deliming solution, such as phosphoric acid at a food-grade level, will dissolve the sediments so it can be flushed away from the heater.

We also do flushing if water is discolored or contains chlorine odor after chlorination procedure, which was used to eliminate various bacteria accumulated in the heater.

How to maintain a water heater

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