Tankless water heaters are an innovation for homeowners hoping to avoid high water bills. An important maintenance step in owning a tankless heater is flushing.

Flushing the water heater clears sediment from the tank. Calcium and other natural minerals filter into the tank in your water. These minerals build up and eat away at the interior of the tank. In short, by flushing them out, you extend the4 life of your tankless water heater.

At PlumbPRO Services we know a few things about tankless heaters and how to keep water flowing smoothly. Here, we’ll go through the steps to flush your heater at home.

What Exactly is the Flushing of a Water Heater?

Your tankless water heater needs to be flushed every year to clean and maintain the unit. The flushing process involves running a cleaner through the heater to remove scale and mineral buildup. This keeps water flowing naturally and reduces the risk of erosion.

Some of the benefits of annual flushes include:

  • Consistent water pressure
  • Extended lifeline
  • Fewer error codes on the status screen of the heater
  • Ongoing hot water availability
  • Fewer breakdowns and needs for maintenance
  • Shorter wait times for water flow

Hot water heaters require different types of annual maintenance, both internally and externally. Flushing the system takes care of a large part of the internal maintenance process.

Tools and Required Equipment

Before you attempt to flush your tankless water heater, you need a few tools. Gather the following items to get started:

  • White vinegar
  • Sump pump
  • Dual hoses to connect to the sump pump
  • Channel locks
  • Rubber gloves
  • Bucket

You should also take a moment to ensure your tankless heater has a pair of isolation valves visible. These should look like metal pipes with nuts and bolts screwed on. Each has a red or blue handle. 

Prepping the Heater for Flushing

With your tools at the ready, pull on your rubber gloves and prepare to flush the water heater. Begin by turning off the tankless heater by shutting off the:

  • Gas line (to extinguish burner)
  • Hot water line (red isolation valve)
  • Cold water line (blue isolation valve)

Now you can begin to drain the heater. To do this, you must remove the hot and cold water caps. Be careful during this step because, as the name suggests, your water heater might contain hot water.

Place a bucket beneath the cold water drain and turn it on. Once the pipes empty, repeat this step on the hot water drain.

Flushing the Heater

With preparation out of the way, it’s time to flush the heater. Before the flushing process commences, remove and clean the prefilter to get rid of any built-on mineral scale.

The pre-filter is on the bottom of the water heater. It needs to be unscrewed, possibly with the channel locks, if it’s difficult to remove. Take a look at the prefilter to assess the level of debris. Clear any scale by dipping and swishing it in the clean water you collected earlier in the bucket.

Now, follow these steps:

1. Empty the bucket, rinse if necessary and empty again.

2. Attach the two hoses to the hot and cold drain lines. Hoses need to be firmly in place to avoid splashing and leaks.

3. Place the end of the hot water hose goes into the bucket.

4. Connect the other end of the cold water hose to the sump pump

5. Pour white vinegar into the bucket.

6. Submerge the sump pump in the vinegar (add more if it doesn’t cover the pump).

7. Plug in the sump pump and run it for about an hour.

As the sump pump runs, it flushes white vinegar through the water heater. After flushing the interior, the vinegar drains into the bucket again.

Once the process completes, dump the bucket and put your heater back together. Remove the isolation valve hoses and replace the caps for hot and cold water. Turn your gas and water lines back on.

It helps to run the hot and cold water in your sink or tub for a few minutes. This expels any residual vinegar solution.

Contact an Expert

If you live in Ambler and are concerned your tankless heater needs to be flushed, we can help. Watch for symptoms like:

  • Low water pressure
  • Errors on tankless heater screen
  • Water that takes longer than usual to warm up
  • No hot water available when needed

If you experience any of these issues, don’t delay. Call PlumbPRO Services today to schedule maintenance.