How to Flush a Tankless Water Heater

Monisha
By Monisha
12 Min Read

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Tankless Water Heaters, often called demand-type or momentary water heaters, only generate hot water when required. They skip the surplus energy linked to storing water heaters, which can result in cost savings. This article helps you to flush your tankless water heater more efficiently. Let us explore how to flush a tankless water heater.

Just as the name suggests, water is heated in an instant without any need for a tank. When a hot water tap is switched on, the cold water inlet valve flows via a device called a heat exchanger inside the appliance and is heated by either a power source or a propane burner. Tankless water heaters are a proper heating substance that provides a hot water supply. There is no prerequisite for waiting for a repository to get sufficient heat. A tankless water heater’s output nevertheless restricts the flow rate.

1.1. Reliable Hot Water Supply

The tankless water heater has no tanks! Sounds weird? Yeah, it isn’t reliant on capacity because there isn’t a tank; instead, it functions on consumption. A tankless water heater heats water as you require it, swiftly delivering hot water to the device only in terms of your use, never failing to make you worthy of your wish.

1.2. Energy Efficiency

You might think the energy consumption will be higher as it doesn’t have a tank, but don’t worry. Here is the reason for lower energy consumption and its energy efficiency: Tank water heaters continuously heat their stored water regardless of whether one must require it. Maintaining temperature requires a lot of energy.

How to Flush a Tankless Water Heater
Source: Elnur/ Unlimphotos

A tankless water heater won’t heat up all day if you are not in need. Hence, you can go for it for the best low energy consumption and high energy efficiency hot water supply in blindfold. Coming to the point you ask yourself how to flush a tankless water heater, it may be a technical one, but you can make sure to flush or clean it yourself without raising any other questions. This process is used to eject mineral buildup inside the tankless water heater.

2. How to Flush a Tankless Water Heater: A Few Tips

The tankless water heaters are flushed in the heater’s internal and external areas. It is required to take maintenance on the tankless water heater once a year per the manufacturer’s mandate. Let’s learn about a tankless water heater’s internal and external flushing. Make use of the right tools provided in the materials required. Internal – Purging the water-touching areas on the tankless and External– Purging the ventilators and the filters of the appliance.

How to Flush a Tankless Water Heater

Note: You or a plumber can do the internal cleaning. However, the plumber can only do the external cleaning, as the components are fragile, so there may be some complications. Look at the water heater’s manual for more information and precautions regarding the flushing process. To avoid accidents, please turn off the electricity so that major accidents won’t occur.

Materials required:

  1. Vinegar solution
  2. Hose
  3. Bucket
  4. Cloth
  5. Submersible pump (optional).

2.1. Turning off the Power Supply

The power supply to your tankless water heater must be turned off before you do any maintenance. Identify and shut off the circuit breaker or power supply switch that controls the tankless water heater. This procedure protects against accidents and electric shocks, ensuring your safety during flushing.

2.2. Turning off the Water Supply

After the power is disconnected, turn off the water supply to stop the water flow. Figure out and close the water heater’s associated cold water service port. Now, you can prevent the cold water flow by using a cold water hose to enter the appliance and ensure no more cold water supply enters during the flushing process.

2.3. Linking the Flushing Hose

Next, start the Flushing process by attaching a hot water hose to the water service port departure isolation valve on the tankless water heater. The unit’s mineral deposit will be drained via this conduit. A bucket should be placed at the other end of the hose, and hoses should be connected to catch the water and debris that will spill from the water heater.

2.4. Actuating the Pressure Release Valve

Once the hose is firmly connected, open the tankless water heater’s gas isolation valves. Any internal gas that has built up can be released through these outlet valves. By opening the outlet valves, you can ensure a secure flushing operation to prevent unforeseen gas surges.

2.4.1. Using a Submersible Pump is Optional

If a Submersible pump is accessible, you could connect it to the bucket’s hoses. Installing a circulation pump to circulate vinegar solution in the tankless water heater constantly can improve its ability to be flushed. Yet it is optional, as this step can substantially enhance the flushing process in a replacement.

2.5. Make the Flushing Solution

Fill the bucket with a vinegar solution following the manufacturer’s instructions. A mixture of equal parts of vinegar and regular water, but not hard water, can often be used to remove mineral deposits and slits. Use a four-gallon or five-gallon bucket large enough to hold the required amount of solution and mind to fill it all the way.

2.6. Open the Hot Water Isolation Valve

After making a four-gallon bucket of the vinegar solution, it is time to open the tankless water heater’s hot water isolation valve through the hot water side. This water valve permits the solution to flow through it, which helps it reach and dissolve the excess mineral deposits inside the water valve.

2.7. Turn on the Cold Water Supply

The hot water taps can be opened, and the cold water isolation valve is accessible. This will cause the tankless water to fill through the cold water isolation valve. This causes the excess mineral deposits and slip scale buildup to dissolve gradually.

The tankless water heater allows the vinegar solution, which takes at least an hour for super cleaning. Depending on the instructions provided by the manufacturer, there can be a small variance in the time. Mineral deposits have become loose in the solution, and large amounts of debris are seen draining out.

3.1. Rinse the Tankless Water Heater

Turn off the hot water valve to safely pause the flow of vinegar solution. If connected, this is the time to pull the submersible sump pump from the hose and bucket.

3.2. Flushing with Fresh Water

After the vinegar solution, rinse the entire water supply valve with fresh water to eject the remaining mineral deposits from the water heater. This demonstrates that the tankless water heater is clean and ready to use.

3.3. Verify Proper Valve Closure

Disconnect the hot water line hose from the hot water exit once the pressure relief from the gas isolation valve has been closed. While doing so, double-check, as the hose can still contain residue or debris from the vinegar solution. Having a towel nearby is a good idea to prevent splashes or spills.

3.4. Reassemble the Parts

Ensure all the inlet and outlet valves, including hot and cold water isolation valves, are shut properly before closing the procedure. A tight seal should be made at the pressure relief, cold water, and hot water isolation valves. Reattach all the separated parts with more care to avoid any leakage. Double-check that all the water lines or the connected hoses will be left unseen and start leaking.

4. Restoring Power to The Water Heater

Once the flushing process is complete, it’s crucial that you, as the homeowner or maintenance personnel, reassemble the tankless water heater. Disconnect two hoses and service valves. At this point, it’s your responsibility to turn the electricity back on, which will inevitably give the device the energy it needs to operate.

How to Flush a Tankless Water Heater 2
Source: Freepik

If a submersible pump is used, ensure it is securely stored or reconnected to another appropriate power supply to be used again. Locate the water heater’s power supply back to normal and turn it on to enable it to operate as intended.

Excellent job! You have successfully flushed the tankless water heater by following the above instructions. By carrying out this maintenance task, you will increase the lifespan and effectiveness of flushing a tankless water heater, which will run a steady and strong supply of hot water when needed.

Final Note

These guidelines should only be used as a general rule while flushing a tankless water heater. For the most precise and comprehensive instructions, it is crucial to consult the manufacturer’s guidelines, which are particular to your tankless water heater model.

If you need more specific instructions or run into any problems, consult the manufacturer’s manual for your water heater or call a licensed plumber. By adhering to the manufacturer’s instructions, you may correctly complete the flushing process and avoid any potential issues. 

FAQ

Q1. Why is it important to Flush a Tankless Water Heater?

A tankless water heater should be normally flushed as part of regular maintenance to guarantee optimal performance and lifetime of the water heater’s efficiency.

Q2. What can happen when a tankless water heater is not flushed?

Deposits of minerals may accumulate. The device could become overheated from fluctuating hot water, which would reduce its effectiveness.

Q3. Are tankless water heaters budget-friendly?

Absolutely! Long-term financial savings are possible with tankless water heaters. They have the potential to use as much as thirty-four percent less energy and last more than twice as long.

Last Updated on by Swati

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By Monisha ICY Intern
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I'm Monisha from Kanyakumari district, Tamilnadu. I'm a M.Phil graduate in English literature and fell love with writing. I worked as a Assistant professor of English in an Arts college. I reflect a varied personality including ambition, and the qualities of generosity and thoughtfulness.