How to Flush a Tankless Water Heater (Best Guide)

A tankless water heater is a modern and energy-efficient way to get hot water on demand. However, over time, minerals and sediment can build up in the heat exchanger, which can reduce the efficiency of your tankless unit. Red One Plumbing experts recommends flushing your tankless water heater once a year to help keep it running smoothly and efficiently.

What Tools do You Need to Flush a Tankless Water Heater?

You will need a few basic tools and supplies. Here is a list of the items you will need:

1. Hoses: You will need two hoses, one for the hot water side and one for the cold water side. The hoses should be long enough to reach from the water heater to a drain or outside.
2. Five-gallon bucket: You will need a bucket to catch the water and debris that is flushed out of the water heater.
3. Submersible pump or sump pump: A submersible pump is used to circulate water through the tankless water heater during the flushing process.
4. Vinegar: Vinegar is an effective solution for removing mineral buildup and other deposits from the heat exchanger of the tankless unit.
5. Power source: Depending on the model of your tankless unit, you may need to turn off the circuit breaker to the unit before flushing.
6. Isolation valves: Your tankless water heater may have service valves (isolation valves) that make it easier to flush the unit. If so, you will need to locate and use these valves during the flushing process. See picture attached of this isolation valves.
7. Wrenches and pliers: You may need a wrench or pliers to connect and disconnect hoses and to turn service/isolation valves.

Having these tools and supplies on hand, you will be prepared to flush your tankless unit and keep it running efficiently. Be sure to consult your owner's manual for specific instructions on how to flush your particular model of tankless water heater.

What is the Purpose of Tankless Water Heater Isolation Valves?

One of the most important components of flushing a tankless unit is isolating the inlet and outlet valves. These isolation valves control the flow of water into and out of the water heater. By turning off these valves, you can prevent water from flowing through the system while you're flushing it. This allows you to safely remove sediment and mineral buildup from the tankless unit without any interference.

Step-by-Step Easy Guide on How to Flush a Tankless Water Heater:

Follow these easy steps on how to flush a tankless water heater and become an expert today while also saving some money.

Step 1: Turn off the power supply

Turn off the power supply to the tankless hot water heater. This will prevent any accidental heating of the cold water during the flushing process.

Step 2: Turn off the water supply valves

Turn off the cold water supply valve and hot water supply valve to the tankless unit. These valves should be located near the water heater.

Step 3: Connect the cold water hose

Locate the cold water inlet valve and cold water isolation valve on the tankless water heater. Connect a cold water hose to the cold water isolation valve and connect the other end of the hose to a sump pump or a submersible pump.

Step 4: Connect the hot water hose

Locate the hot water isolation valve and hot water hose on the tankless unit. Connect a hot water hose to the hot water isolation valve and connect the other end of the hose to a drain or outside.

Step 5: Open the cold water valve

Open the cold water isolation valve, and then slowly open the cold water supply valve to the tankless water heater. This will allow cold water to flow into the tankless unit and push out any sediment.

Step 6: Turn on the pump

Turn on the submersible pump or sump pump to flush the water through the tankless water heater. Allow the water to flow through the tankless for about 45 minutes or until the water runs clear.

Step 7: Turn off the pump and valves

Turn off the cold water supply valve and the submersible pump or sump pump. Close the cold water isolation valve and remove the cold water hose from the tankless water heater. Close the hot water isolation valve and remove the hot water hose from the tankless.

Step 8: Turn on the water supply valves

Open the hot water supply valve and cold water supply valve to the tankless unit.

Step 9: Turn on hot water taps

Turn on the hot water taps or hot water faucets in your home to allow the tankless unit to fill with water again.

Step 10: Turn on the power supply

Once the tankless water heater is filled with water, turn on the power supply to the tankless hot water heater.

When flushing your tankless unit, it's important to use the right hoses. A hot water hose and a cold water hose are essential for connecting your system to the submersible pump and vinegar drain. These hoses should be the correct length and diameter to ensure that water flows smoothly through the system. Using the wrong hoses can lead to leaks, which can damage your tankless unit.

Flushing your tankless unit once a year can help keep it running efficiently and extend its lifespan. Remember to always turn off the power supply and isolate the water flow before flushing your tankless unit. You can use vinegar to clean the tankless unit if you prefer a natural method instead of using a descaling solution. By following these simple steps, you can keep your tankless in great shape for years to come.

What Happens if I Don't Flush out my Tankless Water Heater?

Tankless water heaters are a popular option for many households because they are efficient, take up less space, and provide an endless supply of hot water. However, like any other appliance, they require regular maintenance to function at their best. One essential maintenance task for tankless water heaters is flushing. If you don't flush out your tankless unit regularly, you may encounter several issues.

One of the most significant problems that can arise from not flushing your tankless is mineral buildup. Hard water contains minerals like calcium and magnesium, which can accumulate on the heat exchanger, causing scale buildup. Over time, this buildup can reduce the efficiency of your water heater, leading to higher energy bills and shorter equipment lifespan. If you don't address the mineral buildup, it can cause the unit to malfunction, leading to costly repairs or replacement.

Another issue that can arise from not flushing your tankless unit is damage to the heating element. When minerals accumulate on the heating element, it can cause hot spots that can damage the element. The longer you ignore the mineral buildup, the higher the risk of damage to the heating element. Additionally, ignoring flushing may also lead to clogging and corrosion of pipes, valves, and other components, which can be challenging to repair.

Conclusion

Overall, flushing your tankless water heater is an important maintenance task that can help extend the life of your system. Red One Plumbing, the expert Pearland plumber, can assist you with the process of flushing your tankless water heater and provide professional maintenance for your unit.

By using the right tools and techniques, such as isolation valves, submersible pumps, and descaling formulas, you can effectively remove sediment and mineral buildup from your water heater. With proper maintenance your tankless unit can continue to provide reliable hot water for years to come.

If you want to upgrade to a tankless water heater today give us a call now and get a free estimate for professional tankless installation in Pearland, TX by Red One Plumbing.

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