Flushing a Rheem Tankless Water Heater

How to Flush a Rheem Tankless Water Heater

Even if tankless water heaters are supposed to be more durable than traditional systems with tanks, they still pose a risk for mineral buildup. Truth be told, water doesn’t get to stay in the order in the case of tankless water heaters, but it still gets to affect the pipes and the unit per se.

Why is flushing important?

Water contains minerals (calcium and magnesium) that may buildup, altering the performance of your tankless water heater. Even if there is no tank and water doesn’t spend much time throughout the system, the hardness of water may still affect the efficiency of the water heater.

The deposits of lime and scale can block the water flow and worsen the performance of the water heater. Once a tankless unit struggles to heat the water, its durability will be significantly reduced unless you’re addressing the mineral deposit problem.

Moreover, in areas where the hardness of water is high, you need to install a water softener to help the tankless unit work properly. Using a water softener is essential, but it doesn’t eliminate the need for flushing.

Most tankless water heater manufacturers recommend the users to flush the units once a year for eliminating the buildup of calcium and minerals within the water heater. Should the hardness of the water in your area be high, you may need to do it even more often than once a year. Check the maps online to see the hardness of the water situation in your area.

Luckily for users, some manufacturers indicate when the unit requires flushing. Even if flushing isn’t complicated and doesn’t require special skills, you can also call a professional plumber for flushing the water heater for you.

What are the steps to take when flushing a Rheem tankless water heater?

Many Rheem tankless water heaters are mounted with isolation valves, which makes the flushing more straightforward. When your tankless unit doesn’t come with isolation valves, it\s better that you look for a professional plumber for flushing.

Here’s how to flush your Rheem tankless water heater correctly:

1. Begin with turning off the gas and electricity running to the tankless water heater. You should never flush with the power or has on. Otherwise, you may damage the water heater beyond repair.

2. Continue with the shutting off the primary water supply valve to your tankless water heater. Fundamentally, you check the instructions from the isolation valve manufacturer. It may contain valuable information regarding the valve assemblies.

3. Now it’s time to get a small garden hose on every drain valve. You have to make a connection between the cold water hose and the output of a small circulation pump. You can use a pond pump or anything else similar to the process.

4. Get virgin food grade white vinegar. You have to pour around five gallons of vinegar into the pail.

5. Continue with placing the inlet hose of the pump and the drain hose from the hot water into the jug.

6. You have to open the drain valves and to turn the pump on. It’s not a fast process, and you have to be patient. Let the vinegar solution to circulate through the system for 45-60 minutes.

7. Now you have to turn the pump off and to drain the vinegar from the tankless water heater. Don’t forget to close the cold water drain valve.

8. You also need to open the main cold water supply valve, letting the fresh water to run through your tankless unit. Let it circulate for at least 5 minutes so that it eliminates every trace of vinegar from the system.

9. Continue with closing the cold water main valve and removing the water filter screen placed in cold water inlet of your tankless water heater. You should remove any piece of dirt or sediment before putting the filter back on. Always check the manual that comes with the tankless water heater for all the details.

10. You’re getting close to the end of flushing. It’s time to turn the shut-off valves on and to run the hot water tap for removing any air from the water lines. Keep in mind to take a look at the system carefully so that there are no leaks.

11. It’s time to turn electricity, gas, and remote control thermostat on. You can safely set the temperature as planned.

12. Let the hot water run from various locations to see how your tankless water heater is performing.

Last piece of advice

Flushing a tankless water heater (no matter if it’s Rheem or not) is fundamental for its performance. Don’t skip it just because you don’t have the skills, and ask for professional help instead.

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