How Do I Flush My Tankless Water Heater?

How to Flush a Tankless Water Heater in 7 Simple Steps

  1. Have you noticed that your tankless water heater is no longer providing you with hot water?
  2. Did you notice a decrease in the amount of water that was flowing from your water heater as well?
  3. If you understand how to flush a tankless water heater, you can take care of these problems.
  4. Hard water minerals can accumulate on the heating elements and other components of the water heater, lowering the efficiency with which the water is heated.

Tankless water heater manufacturers recommend flushing and cleaning your tankless hot water heater at least once a year, which is why you should do so.Additionally, you may learn more about water heaters that are specifically built for hard water by visiting this page.This post will show you how to flush your tankless water heater and maintain it operating at peak performance.

Things You Need for This Tutorial

The process of flushing a tankless water heater is not difficult if you prepare the necessary supplies before beginning the real process. Here is a list of the supplies you will need to clean a tankless water heater:

Owner’s Manual

  1. When it comes to cleaning and flushing their equipment, tankless water heater manufacturers offer specific suggestions.
  2. They also have preferences when it comes to the cleaning solution that may be used on the water heating system.
  3. I recommend that you read the maintenance recommendations in your handbook before flushing the device.
  4. Also included are the tools required for such an activity as well as the safety considerations that must be adhered to during the process.

Cleaning Solution

  1. When it comes to cleaning the tankless water heater, several manufacturers only advocate pure, undiluted, virgin, and food-grade white vinegar as a solution.
  2. This vinegar-based product eliminates mineral deposits and limescale accumulation without endangering the health of your family.
  3. Some tankless water heater manufacturers, on the other hand, advocate using a specialized cleaning for their products.
  4. Because of this, it is always a good idea to consult the owner’s handbook for detailed instructions and suggestions.

Other Tools

  1. For a gas tankless water heater, you’ll need a big bucket, a submersible pump, and water hoses to connect the water heater’s service ports to your home’s plumbing system.
  2. The use of a screwdriver is also required for opening and shutting the access panel on the water heater.
  3. Additionally, a non-contact voltage detector will be useful in confirming that your water heater is entirely turned off before cleaning it.

Steps for Flushing a Tankless Water Heater

Step 1. Read the manual.

  1. The cleaning technique for tankless water heater systems differs from manufacturer to manufacturer.
  2. For example, Rinnai may have a different technique of cleaning its tankless water heaters than Rheem or other models, and this may differ from other brands.
  3. As a result, I always recommend consulting the owner’s handbook for precise cleaning recommendations pertaining to the device you wish to clean before beginning.

Step 2. Disconnect the tankless water heater from its power source.

  1. Contrary to popular belief, even a gas tankless water heater includes an electrical connection that powers the electronic components within the unit’s construction.
  2. Because of this, I recommend that you unplug the gadget from the electrical outlet.
  3. It would be better if the tankless water heater’s power source was disconnected from the circuit breaker panel before continuing.
  4. This technique is for an electric tankless water heater, which you will be installing.

Make sure the electrical current in your system is safe by opening the access panel and using a non-contact voltage tester to examine it.When it comes to determining whether or not voltage is present in a water heater, the Fluke 1AC-A1-II VoltAlert is a dependable instrument that homeowners may utilize.

Step 3. Close the gas valve, the water supply line, and drain the water.

  1. Locate and turn off the water shutoff valves on the tankless water heater if necessary.
  2. It is recommended that you close the shutdown valve on the main water supply line if your device does not have these measures.
  3. If you have a gas tankless water heater, I also recommend that you close the gas isolation valve on the water heater before turning off the water supply.
  4. Open all of the faucets in order to drain the water from the supply line.

In addition, I recommend that you carefully open the hot water pressure release mechanism in order to alleviate pressure from the system.

Step 4. Prepare the tankless water heater.

  1. If you have a gas tankless water heater, you may be able to skip this step.
  2. Remove the heating elements from the electric water heater by releasing the screws that hold the wires in place and unscrewing the hexagonal brass cap from the element.
  3. Cracks and other symptoms of deterioration should be looked for on the water heater components.
  4. After you have cleaned your tankless water heater, you may replace the heating element with a new one.

It is possible to clean the water heater components in the copper heating chamber if they are placed in the chamber.

Step 5. Set up the flushing system.

  1. The cold and hot water service ports on the tankless water heater should be located, and the flexible tubings should be connected to both.
  2. Get a huge bucket and put a submersible pump in the center of the bucket.
  3. Afterwards, connect the cold water line to the pump.
  4. The free end of the hot water line should be placed in the container or bucket.

Fill it with four gallons of a tankless water heater cleaner or four gallons of pure, food-grade, virgin white vinegar, if needed.Some water producers give suggestions for descalers or cleaners, although the majority do not.The majority of corporations, on the other hand, solely prescribe white vinegar.Open the copper heating chamber and fill it with pure, food-grade virgin white vinegar before putting it back together.You may also use a tankless water heater descaling solution that is recommended by the manufacturer.

Step 6. Flush the tankless water heater.

  1. Open the cold and hot water service ports on the tankless water heater, and then turn on the submersible pump to complete the installation.
  2. Allow at least an hour for the white vinegar or cleanser to circulate throughout the system.
  3. It’s possible that the water from cleansing the tankless water heater with vinegar becomes blue after a while.
  4. The fact that the solution contains dissolved copper oxide from your tankless water heater should not be a reason for concern.

Turn off the water pump and empty the cleaning or vinegar solution from the tankless water heater to prevent it from overheating.In order to proceed, switch off the cold water service port and disconnect the tubing from the pump.Allow at least 10 minutes to pass after turning on the supply line’s shutdown valve to drain out any residual vinegar or cleanser.Close the valve and continue to drain the water until the water is completely gone.Disconnect the hot water supply line from the service port and remove the tubing.Check the cold water input first, and then the hot water supply pipe to see whether there is a filter.

Remove these filters and thoroughly clean them in the sink, making sure there are no sediments or debris left behind.Make sure the white vinegar or cleanser has been sitting in the copper heating chamber for at least 90 minutes before using it.However, most experts recommend that you wait two hours to verify that any limescale and mineral deposits on the heating components have been completely dissolved.It is necessary to replace the water heater elements as well as reattach the electrical lines.

  • After that, open the shutdown valve on the cold water line to allow water to flow into the heating chamber.
  • Afterward, open the hot waterline shutdown mechanism as well as all of the faucets in your home once a few minutes have passed.
  • Continually run the water for five to ten minutes, or until there is no longer any scent of vinegar or cleaner coming from the faucet.
  1. In addition, air is removed from your water line as a result of this procedure.

Step 7. Finish up.

  1. Before opening the shutdown valves for the cold and hot water lines, make sure the filters are properly installed and secured to the hot water line and cold water input.
  2. Reinstall the access panel and fasten it with screws to keep it in place.
  3. Turn on the gas supply line’s shutdown valve and reconnect the heating unit to the electrical outlet, if it has been disconnected.
  4. Alternatively, you can switch on the electricity at the circuit breaker panel.

Close all faucets and turn off the cold water valve to prevent water from leaking.Remove and thoroughly clean the cold water supply input filter to verify that no debris is left behind before reinstalling the filter.At the circuit breaker panel, secure the access panel and turn on your water heater to begin using it.Silver Cymbal’s video on cleaning and flushing tankless water heaters is really helpful, and I recommend it.I recommend that you take the time to view the five-minute video.


  1. Using vinegar or a suitable cleaning/descaling solution in the heating chamber or a bucket is all it takes to flush a tankless water heater, which is simple and straightforward.
  2. The final step in the tankless water heater cleansing process is to allow the solution to settle for several minutes before dumping the cleaner into the sink.
  3. I hope you enjoyed this lesson and will spread the word about it to your friends and colleagues.
  4. You may also send me questions or comments on this guide, and I would be pleased to respond to you and share my ideas on the subject.

How To Flush A Tankless Water Heater (Easy DIY Guide)

Tankless water heaters can represent a significant financial commitment. As a result, understanding how to correctly flush them might provide a significant return on your investment. By cleaning your tankless water heater properly, you can ensure that you are getting the most out of your installation. Continue reading for more information on how to install a tankless water heater.

Do Tankless Water Heaters Need to Be Flushed? 

  • In some cases, tankless water heaters can become clogged with calcium and other mineral debris from the water they heat. Keep your machine running efficiently and in good operating condition by flushing it once every year to year and a half, depending on how often it is used. When you flush your machine, the filter within will be cleared out, allowing it to filter water correctly once again. For example, cleaning your water heater may reduce clogging, scale build-up, and noise, improve heating speed, extend the life of your equipment, and significantly lower your utility bills, among other benefits.

Using a clogged drain to flush your heater on a frequent basis might impair its efficiency and cause difficulties in the future.

What Happens If You Don’t Flush Your Tankless Water Heater? 

  • Mineral deposits are found in the majority of water sources. It is possible that these mineral deposits will accumulate in your tankless water heater filters. The greater the concentration of minerals in these filters, the less efficiently the heater can perform its function. Tankless water heaters that are not cleansed regularly accumulate a significant amount of residue on their filters, which reduces the efficiency of the unit. The following consequences of failing to flush your tankless water heater on a regular basis: Less hot water in your pipes
  • higher energy bills
  • inefficient heating
  • leaking water heater
  • water damage
  • broken filters
  • and failure to flush your tankless water heater.

Because a faulty water heater might result in a pricey replacement, you should get into the practice of cleansing your system on a regular basis.

How Often Should You Flush Your Tankless Water Heater? 

  • You should cleanse your tankless water heater at least once every 12 to 18 months, depending on how often you use it. Mineral residue on your filters can have a negative influence on the functioning of your filters if left on for an extended period of time. Depending on the amount of water in your area and the frequency with which you use your heater, you may need to change your filter more frequently than once every 12 months. The following are some of the most common symptoms that you need to change your filters: no hot water
  • strange scents
  • loud noises from the heater unit
  • rusted or discolored water
  • decreased water temperature

It is possible that failing to flush your heater can result in long-term troubles and perhaps irreparable damage to the machine.

Preparing a Tankless Water Heater for Flushing (Safety Precautions & Tools) 

  • The following are some safety measures and tools to keep in mind before beginning work on your tankless water heater. Tankless water heaters produce extremely hot water, making it potentially hazardous to handle them. The water is quite hot, especially if it has only been flowing for a short period of time.
  • When flushing your tankless water heater system, stay away from using strong chemicals. Harsh chemicals, such as bleach, might permanently harm internal components of your water heater, necessitating the installation of a new unit.
  • Make sure you have your water heater manual on available in case you need to examine it or develop a new one.
  • The following tools are required: a wrench, pliers, screwdriver, a washing machine hose, a voltage tester, four litres of vinegar, a submersible pump.

How to Flush a Tankless Water Heater (Step-By-Step Guide) 

1. Gas-Powered Water Heater 

  1. Place the tankless heater’s electrical power in a convenient location and turn it off. Check the wires that are connected to the terminal with the voltage tester to ensure that it is not switched on.
  2. 2Close the shut-off valves for the hot and cold water. Close these valves to guarantee that cold water does not enter the unit and your home’s plumbing system. 3Open the how water pressure release valve to ensure that hot water does not enter the unit. Keep an eye on the submersible pump because any water that is released will be extremely hot.
  3. 4Connect one end of an extension hose to the cold water service port and another end to the submersible pump.
  4. 5Place the submersible pump into a bucket and connect one end of an extension hose to the hot water service port. Next, insert the end of the second hose into the bucket with the pump
  5. 6Fill the bucket with at least 4 gallons of food-grade white vinegar and run the pump until the vinegar is completely dissolved. It should not be necessary to dilute the vinegar.
  6. 7Open both the hot and cold service ports.
  7. 8Let the submersible pump operate for approximately 2 hours without interruption. 10Remove both ends of the second hose from the system and place them in the drain or outside to enable the vinegar to work its way through the system and dissolve any accumulation
  8. 9Close the pump and empty the bucket of vinegar down the drain or outside. Allowing water to run through to flush out any residual vinegar in the system after removing the hose connected to the cold water port, closing it, and opening the cold water shut-off valve
  9. 11 After about 10 minutes, turn off the cold water shut-off valve
  10. 12remove the second hose and turn off the hot water service port
  11. and Make sure that both the hot and cold water shut-off valves are open.
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2. Electric Tankless Water Heater 

  1. 2Open all of your home’s taps to drain any remaining water from the electric tank. 3Close the hot water valve and check the heater unit with a voltage tester to ensure that all electricity has been turned off. 4Remove the heater’s electrical heating components. Using the wrench and pliers, carefully remove the heating element from the tank. Ensure that any broken or cracked parts are replaced.
  2. 5Place the heating elements in the unit chambers and fill them with white vinegar.
  3. 6Leave it soaking for at least 2 hours. 7. Drain the vinegar from your system and reinstall the heating components in their proper locations on the tankless unit. Do not dilute the vinegar by adding water. 8. Check for good wiring connections between the heating element and the circuit breaker. 9Opening the cold water shut-off valve and waiting for the tank to fill Once it has done so, open the hot water shut-off valve.
  4. 9While the tankless unit is filling up, be careful to check for any leaks.
  5. 10Turn on various hot water faucets throughout your home and let them run for 5-10 minutes. As a result, the vinegar will be flushed through the system and out the drains.
  6. 11Check the line frequently for air pockets that may have developed while you were draining the vinegar from the system.

Tankless Water Heater Flush Kits 

Tankless water heater flushing kits are available from a variety of manufacturers and are intended to assist you with the procedure. You may not always need a kit, but they can be beneficial because they include all of the hoses and cleaning solutions that you will need to get the job done.

3. How To Flush Rinnai Hot Water Unit 

  1. It is not difficult to flush a Rinnai water heater.
  2. First, turn off the hot and cold water shutoff valves on the water heater.
  3. Then attach a pond pump and a garden hose to the valve that has been serviced.
  4. After flushing a combination of about 4 gallons of vinegar through the system, attach a hose to the second service valve to complete the process.

The pump and the end of the hose should be placed in the bucket.When you’re finished, remove the hoses and re-open the shut-off valves if necessary.

4. How To Flush Rheem Hot Water Unit 

  1. Your heating unit’s electrical and gas supplies should be disconnected.
  2. Then, by moving the handle in the clockwise direction, cut off the cold water supply.
  3. Then put a garden hose through the drain valve and into the heater tank to drain the water.
  4. Drain valves are often found in the lowest portion of the tank, close to the gas valve on most Rheem systems.

Place one end of the hose outdoors and turn on a hot water faucet to fill the rest of the hose.Allow the water to drain from the heater before turning on the cold water supply line to the house.Allow it to circulate through the system through the hose until the water becomes clean.Finally, turn off and leave the drain valve open while the tank is filled with water.Removing the hose and reconnecting the electrical and gas supply lines will complete the task.

5. How To Flush A Navien Hot Water Unit 

  1. When it comes to flushing a Navien hot water heater, you should follow these steps.
  2. Remove the gas and electrical power wires from the system.
  3. Then, remove the lid and disconnect the machine from the wall outlet.
  4. Remove the cold air intake filter, thoroughly clean it, and replace it in its original location.

Afterwards, drain the water heater by shutting off the cold and hot water valves, attaching hoses to the service valves, and emptying the unit into a pail of water.Removing the dirt trap from your system and pumping vinegar through the system with a sump pump and hose configuration will help to clean it.Remove the cover and reconnect the electricity and gas to the unit after flushing the system and opening the valves.Replace the cover and restart the system.

6. How To Flush Noritz Hot Water Unit 

  1. Turn off the gas to the unit, as well as the hot and cold water valves on the unit.
  2. Remove the drain covers on both sides of the unit, turn on the drain valve, and allow the unit to drain into a large bucket.
  3. Hook up the pump with a hose and set it in the bucket to use it.
  4. Connect the hose’s other end to the cold water outlet on the faucet.

Connect a second hose to the hot water drain valve and place the other end of the line in a bucket to catch the water.Pour 4 gallons of vinegar into the system and let it sit for roughly 2 hours.Approximately halfway through the solution, change it.Take out the pump as well as the cold water line hose, but leave the hot water line hose in place.Open the cold water shut-off valve and allow the system to drain into a bucket until it is completely empty.

People also Ask (FAQs)

Where can I buy tankless water heater flush kits? 

Tankless water heater flush kits can be purchased at your local hardware shop, such as Lowe’s or Home Depot, for a little fee. It’s also possible to purchase them through internet merchants such as Amazon.

How much does it cost to flush a tankless water heater? 

If you do it yourself, it will cost you very little. A tankless water heater flush kit may be purchased for anywhere from $40 to $130.

What is the average life of a tankless water heater? 

If properly maintained, the typical tankless water heater may survive for up to 20 years in most cases.

Can I use CLR to clean and flush my tankless water heater? 

In addition to distilled vinegar for cleaning your water heater unit, you may use CLR to clean your water heater unit.


Water heaters are an integral component of your home’s water distribution system. Keeping your tankless unit clean is critical if you want it to last as long as it should. Cleaning the filters in your tankless unit can help to guarantee that it continues to operate efficiently for a long period.

How to Flush a Tankless Water Heater (Step-by-Step Procedure)

  1. Please keep in mind that this content may contain affiliate links.
  2. This means that, at no additional cost to you, we may gain a small profit on purchases made via our links.
  3. Knowing how to properly clean a tankless water heater will help you get the most out of your investment in terms of efficiency and durability as possible.
  4. Consider the following steps in detail, as well as some helpful tools and crucial considerations.

The Importance of Flushing Tankless Models

  1. Tankless water heaters are less expensive and more energy efficient to operate when compared to standard water heaters.
  2. They also demand significantly less maintenance and operating area.
  3. Therefore, it is critical to understand why and when a tankless water heater should be flushed, as well as how to flush a tankless water heater, whether it is gas or electric.
  4. Examine how the naturally existing sediment in your water impacts the heater, as well as how to make flushing more convenient and safer.

Tankless Water Heaters and Scale Buildup

  1. Anyone who has ever had a conventional water tank is aware with the necessity of flushing the tank on a regular basis in order to remove silt from the system.
  2. Tankless heaters are not an exception to this rule.
  3. Hard water includes minerals that can cause lime scale to build up on the surface of the water.
  4. An explosion from the accumulation is less likely to occur with a tankless heater than it is with a standard tank model, but it can still cause some expensive complications.

The heat exchanger is particularly susceptible to scale buildup.As lime deposits accumulate in the unit, the heat exchanger is forced to work harder and more often in order to deliver hot water.This can result in a considerable reduction in the lifespan of this component, as well as a large rise in your electricity expenditures over time.To make matters worse, most warranties do not cover the effects of lime accumulation.

How Often Should You Flush a Tankless Water Heater?

Tankless water heaters should be cleansed at least once a year to ensure that they operate at peak performance levels. However, the hardness of your water plays a role in this, and if your home’s water is very low in quality, you may find it necessary to flush two to three times a year. To a certain extent, a sediment trap or a water softener can help with hard water.

Isolation Valves

  1. It is critical that we explain isolation valves before proceeding with the rest of the processes.
  2. As the name implies, an isolation valve allows you to isolate (isolate) a segment of your pipeline’s liquid or gas supply without having to shut down the entire supply line (as would otherwise be the case).
  3. Essentially, the word is equivalent with the term ″shut-off valve.″ From your stove to your toilet, a wide range of objects in your home are equipped with some type of isolation valve for maintenance or emergency purposes, depending on the item.
  4. These valves are available in a variety of designs, but they all fall into two fundamental categories: those that move in a rotational direction (such as a ball or butterfly valve) and those that move in a linear direction (ex: glove or diaphragm valves).

In some cases, depending on the manufacturer and if a professional installed your tankless heater, an isolation valve may or may not be put on your tankless heating system.If your heater does not have this function, we highly advise you to get one installed as soon as possible and to engage a professional to flush the system while you wait, since it may be a significant safety issue while doing a flush or other maintenance tasks.

Using Pumps and Flush Kits

  1. A submersible pump is one of your greatest friends when it comes to flushing a tankless water heater.
  2. Due to the fact that you do not have enormous volumes of water to sweep up and drag the sediment out, a quality pump such as the 91250 from Superior Pump will save you hours, if not days, of manual flushing time.
  3. Flushing will necessitate the use of a large bucket to contain the pump, since there is no easy drainage option available, as there is with a typical tank model, necessitating the use of a submersible model pump.
  4. A decent flush kit is yet another useful piece of equipment.

These kits often include everything you’ll need, including a pump, bucket, descaler, and hoses, among other things.When you own a tankless heater, having a maintenance kit on hand might be a fantastic investment, even if it is not strictly essential.My favorite kit is made by My PlumbingStuff, and it not only works well and is simple to use, but it is also ecologically friendly down to the last component, making it the greatest tankless water heater flush kit in my opinion.

How to Flush a Gas Tankless Water Heater

  • Consult your water heater’s instruction manual for precise directions on how to cleanse and descale the unit. Rinnai, Rheem, and Noritz are the three most popular manufacturers of gas tankless versions. For your convenience, we’ve included particular guidelines for each of the brands listed below: Procedures for flushing a Rinnai tankless water heater, a Rheem tankless water heater, and a Notritz tankless water heater are all available online.

No matter what type of gas tankless water heater you have, there are a few steps in the flushing process that must be completed in the proper order, but they are all rather straightforward to complete.

Phase 1: Preparation

  1. Disconnect the electrical power source that is feeding the heater.
  2. Remove the access panel and check the terminal with a non-contact voltage tester to ensure that there is no longer any power coming through it.
  3. Discover where the gas isolation valve is located and close it.
  4. To prevent any water from entering the unit while you are working, locate the hot and cold shut-off valves and close them accordingly:
  5. To release any pressure, locate the hot water pressure relief valve, which should be located somewhere along the hot water line. Take cautious, because the hot water will be quite hot
  6. The service port for cold water and the service port for hot water will be separate. Hoses should be connected to both of these ports.
  7. Fill a five-gallon bucket halfway with water and submerge your submersible pump.
  8. The cold water pipe should be connected to your pump.
  9. Into the bucket, insert the free end of the hot water line
  10. Pour four gallons of undiluted virgin food-grade white vinegar into a pail and set it aside. (Note: As a heavy-duty alternative, Noritz recommends mixing one gallon of CLR with three gallons of water.

Phase 2: Flushing

  1. Make sure that the hot and cold service ports are open and that the pump is running.
  2. Make sure the vinegar is allowed to flow through the heater for at least one hour (longer if the pump runs at less than four gallons per minute). As a result of this, the scale is broken down and the silt is flushed away.
  3. Turn off the pump and empty the vinegar into a trash can.
  4. Close the cold water service port and disconnect the hose that is connected to it.
  5. Open the cold water shutoff valve to let any residual vinegar to be flushed out through the second hose into your bucket for around ten minutes.
  6. Close the cold water shut-off valve on your faucet.
  7. Allow the water to drain completely before disconnecting the second hose.
  8. Close the hot water service port on the boiler.
  9. Remove the cold water intake filter as well as the hot water inline filter (if applicable).
  10. Remove any retained sediment by flushing the filters with water in a sink.

Phase 3: Cleanup

  1. Reinstall the filter(s) in a secure manner, and then turn off the hot and cold water valves
  2. Replace the access panel
  3. turn on the gas shutoff valve
  4. and remove the access panel.
  5. The electrical supply should be reconnected.

How to Flush an Electric Tankless Water Heater

  • Flushing out an electric tankless water heater is a little different than cleaning out a gas tankless water heater, and some disassembly may be necessary. Generally speaking, Navien models are easier to understand, however some Takagi models require additional steps in order to properly place the water control valve. Technique for flushing a Navien tankless water heater
  • procedure for flushing a Takagi tankless water heater

Descaling an electric model is similar to descaling a gas model in that it may be divided into three stages.

Phase 1: Preparation

  1. Switching off the electrical power at the circuit breaker
  2. Close the cold water shut-off valve on your faucet.
  3. Open your taps to let any water that has accumulated in the heater to drain
  4. Close the shut-off valve for the hot water supply.
  5. Remove the access panel and check the terminal with a non-contact voltage tester to ensure that there is no longer any power coming through it.
  6. Disconnect the wires from the heating elements by removing the screws that hold them in place.
  7. Extraction of the heating element is accomplished by loosening the hexagonal brass top of the heating element in a counterclockwise manner
  8. Make a visual inspection of the heating components for evidence of damage. A broken element should be replaced as soon as possible.
  9. Storage of the heating elements in the cooper chambers of the heater to allow for cleaning of the heating elements
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Phase 2: Flushing

  1. Fill the cooper chambers with virgin food-grade white vinegar that has not been diluted
  2. Pour vinegar into the chamber and allow it to rest for 90 minutes to two hours. Using this method, you may break up any scales on the components.
  3. Remove the vinegar from the mixture.
  4. Replace the heating elements and reattach the cables as necessary.
  5. Open the cold water shut-off valve and let the tank to fill up with cold water
  6. Observe the tank for any evidence of leakage (the paper towel test is quite effective in this situation)
  7. To turn off the hot water, turn the shutoff valve.
  8. Fill the sink with warm water from various hot water taps and let the water run for about five minutes to flush out the vinegar and remove any air pockets from the line

Phase 3: Cleanup

  1. Turn off all hot water faucets in your home.
  2. Close the cold water shut-off valve on your faucet.
  3. Clean any dirt from the cold water input filter by flushing the filter under a cold water faucet.
  4. Replace the filter in a secure manner.
  5. Power should be restored at the breaker once you close the access panel

How do I flush clean my Rinnai tankless water heater? (R)

  • It is possible for a tankless water heater to collect mineral build-up over time, which can corrode the walls of the heating chamber within the tank. For regular maintenance and cleaning of your tankless water heater, it is necessary to rinse those mineral deposits out at least once a year using a hose. Follow this straightforward procedure to guarantee that your tankless water heater performs and operates at peak efficiency. Please take the time to go through all of the directions before starting, as you’ll want to ensure that you have all of the essential items on hand for the procedure. Remove the tankless water heater’s power supply by following these steps: 1. 2. Turn off the main gas valve or the circuit breaker for any electrical equipment that are not in use. 3. Turn off (close) the three water valves that are connected to your tankless water heater. 4. During the cleaning procedure, this stops cold water from entering the water heater and hot water from exiting the water heater.
  • The water valves are comprised of three parts: a cold water valve (which is colored blue), a hot water valve (which is colored red), and a main valve, which is responsible for bringing water into your home.
  • 4. Remove the purge port valve caps from the purge valves situated on each of the cold and hot water valves one at a time, taking care not to damage them. The purge valves are distinguished by their little handles that mimic the letter ″T.″
  • In order to alleviate any pressure that has built up inside the valves and to avoid excessive hot water from pouring out during the cleaning process, this step must be carried out.
  • Because there may be pressure when removing the purge port valve covers, it is critical to double-check that the hot water valve has been properly switched off for your safety.
  • Make sure to handle each cap with care to ensure that the rubber sealing discs remain in place. These are required in order for your valves to operate correctly.
  • 5. Connect a hosing line to each of the three valves in the system. Tankless water heater hosing lines are available at any home improvement store that carries water heaters if the manufacturer did not include them with your tankless water heater. There must be adequate length between the water heater and the bucket for the hosing lines to be effective.
  • Please refer to the tankless water heater manufacturer’s instruction manual, or contact the manufacturer directly if you require specific instructions on how to do this step.
  • In certain situations, you may be required to utilize a sump pump and connect hoses in order to discharge and flush water from the tankless water heater’s cold and hot water valves during this operation.
  1. 6.
  2. Twist the purge port valves so that they are perpendicular to the positions of the cold and hot valves, and then close them.
  3. 7.
  4. To clean your tankless water heater, fill a 4-gallon (15.1-liter) bucket halfway with undiluted white vinegar.

Never apply any type of chemical solution on your skin.Using chemical cleaning solutions in your house might be particularly damaging to your health because the majority of the water used for drinking and bathing is likely to pass via your tankless water heater.

8. To complete the flushing and draining operation, according to the directions provided in your manufacturer’s handbook. It is possible that this treatment will take up to 45 minutes.

  1. 9: When the flushing operation is finished, shut the purge port valves by twisting the T-shaped handles.
  2. 10.
  3. Disconnect and remove the hosing wires from each of the valves in the sequence listed.
  4. 11.

Attach the purge port valve caps to the purge valves using the hose clamps.Tighten the caps all the way down and securely.Take care not to overtighten the caps, as this might cause the rubber sealing discs within to crack or shatter.

12. Refer to your water heater’s owner’s handbook for specific advice on how to properly restart the unit. It may be necessary to rotate and open the cold and hot water valves such that they are parallel to the position of the main valve in order to achieve this result.

Pick a sink tap within the house and turn on the hot water gently, allowing enough time for air to travel through the pipe. Make sure to keep the water running until it flows consistently and there is no air escaping (you may recognize this by a slight sputtering sound). Depending on the size of the air pockets, it might take up to 2 or 3 minutes for them to all to escape.

Common Questions We Have Answers To!

What is a tankless water heater?

Return to the top of the page A tankless hot water heater, also known as an on-demand water heater or an instant hot water heater, provides hot water on demand. They do not require the use of a storage tank since they heat the water as it travels through the device.

Why install a tankless water heater?

Tankless hot water heaters provide clients with a limitless supply of hot water at a reasonable cost. A tankless hot water heater should be installed by a registered professional plumber so that you and your family may take back-to-back showers without ever running out of hot water!

Do tankless water heaters save money?

Yes! Tankless water heaters are more cost-effective in the long term than traditional water heaters. A tankless water heater’s base price may be more than the price of a regular hot water tank, but these water heaters can be up to 34 percent more energy efficient than a traditional hot water tank and can last more than twice as long as a traditional hot water tank.

Tankless gas water heater or tankless electric water heater – which one?

Return to the top of the page This is one of the most often asked questions when it comes to water heaters. People are sometimes forced to choose between natural gas and electricity. If, on the other hand, you are given the option, there are certain things to consider.

Thermoelectric Water Heater with No Tank Gas units are designed to burn natural gas or propane, and the majority of manufacturers provide both a natural gas and a propane version of their product. The use of gas water heaters may be advantageous for big households with a high demand for hot water. These devices, on the other hand, require more maintenance and are less energy efficient.

Electric Water Heater Without a Tank Electrical water heaters are less complicated to troubleshoot and consume less energy than gas water heaters. Furthermore, electricity costs have a tendency to change less than natural gas prices.

What does it mean to winterize a tankless water heater?

  1. Tankless water heaters must be winterized in order to function properly in cold weather.
  2. Due to the fact that most manufacturers do not cover damage caused by freezing under their warranties, they may require a little additional attention during the colder months.
  3. Learn why winterizing your tankless water heater is so important, as well as how to get your tankless water heater ready for the winter, by reading this article.

What does flushing a tankless water heater mean?

Flushing a tankless water heater is simply the process of cleaning it out using a descaling chemical, which eliminates any sediment or buildup that has accumulated.

What happens if I don’t flush out my tankless water heater?

Mineral deposits may form over time. This might result in a clog within the unit, which could prevent regular heating activity from taking place. Your hot water might also vary, causing the system to overheat and reduce its overall efficiency.

What are the benefits of flushing out a tankless water heater?

  • Reduces the likelihood of clogging: Tankless water heaters can accumulate mineral backing, which can be flushed out using a descaling chemical to reduce the likelihood of clogging
  • and
  • Noise reduction: If your tankless water heater is creating noise, it is likely that there is a buildup of sediment within the tank. If the noise goes away on its own, it is possible that the accumulation has become so hardened that water is no longer able to travel through it efficiently.
  • Acceleration of the heating process: The greater the amount of buildup in the tankless water heater, the longer it will take for the heat to move. Flushing your tankless water heater on a regular basis might help it operate at peak efficiency.
  • Equipment lifespan: By flushing out the tankless water heater with a descaling solution, you are extending the life of the tankless water heater.
  • Cost: If your tankless water heater is clogged, it makes it more difficult for the water to move through, increasing the amount of energy required to create hot water, resulting in higher costs! Flushing on a regular basis boosts water flow and has the potential to save expenditures dramatically.

How often should I have my tankless water heater flushed out?

Tankless water heaters should be cleaned out once per year to two years, depending on their age.

Why should I have my tankless water heater flushed out so regularly?

Tankless water heaters need to be cleaned out more frequently in the areas near Rochester, NY that are supplied by the Monroe County Water Authority since the water is somewhat hard.

What is hard water and how does it impact my tankless water heater?

  1. Water hardness is a measure of the amount of minerals present in a body of water.
  2. Monroe County’s water is regarded to be somewhat hard by most standards.
  3. In one gallon of hard water, it comprises between 5.6 and 7.6 grains of calcium carbonate.
  4. Homeowners in Rochester, NY and Monroe County do not require a water softener; nonetheless, flushing out your tankless water heater with a descaling solution is extremely vital owing to the mild hardness of the water in Rochester and Monroe.

Do I need a professional for flushing out my tankless water heater?

Yes! It is always a good idea to contact a licensed professional plumber when you have a plumbing emergency.

Do I need to call a plumber near me just to have part of my tankless water heater cleaned?

Yes! If you are experiencing problems with your tankless water heater, it is possible that a specific section of it has to be cleaned. Because there are several parts to a tankless water heater, it is always recommended that you consult with a licensed professional plumber for assistance with your water heater requirements.

What brands of tankless water heaters does Pride Plumbing carry?

  • When it comes to tankless water heaters, we at Pride Plumbing of Rochester only provide the highest-efficiency models that are helpful to your house. The Navien brand of tankless water heaters is one that we sell
  • Navien tankless water heaters are energy star rated, which means that they save both energy and money over time. These tankless water heaters can also be used in conjunction with the RG&E rebate, which can result in a $200 savings! These water heaters also have a sleek appearance and are 80 percent less in size than standard tank water heaters.

Are you thinking, “who is a plumber near me that can help with my tankless water heater?”

We are here to assist you! Call (585) 271-7150 to speak with your local plumber, or use the online scheduling tool to make an appointment. Save $250 on a tankless hot water heater by using our promo code!

How to Flush Out Tank less Hot Water Heater

  1. With contemporary technology and electric gadgets, science has made life easier for everyone.
  2. It is imperative that you are familiar with the operation of these machines.
  3. Tank-less heaters are an example of these types of equipment, and you may already have one in your house.
  4. First and foremost, you should be aware of what a tank-less hot water heater is.

The solution to this question is A tankless water heater is also referred to as an in-line, instantaneous, continuous flow, flash, on-demand, or instant-on water heater, depending on the manufacturer’s terminology.These heaters rapidly heat water as it passes through the device, and they do not keep any moisture within the device itself, with the exception of the heat exchanger unit, which does.Knowing how to flush out a tankless hot water heater can assist you in getting the most out of your equipment and saving money in the long term.Most tankless water heaters are shielded against severe minerals and residues, therefore tankless water heater maintenance is often overlooked when thinking about tankless water heaters.Let’s have a look at the procedure, a few of handy instruments, and some important safety considerations to remember.

Importance of Flushing out Tank-less Models

  1. When compared to standard water heaters, tank-less water heaters are both less costly and more energy efficient.
  2. It is possible to save 108$ a year on heating expenditures by using tank-less gas water heaters instead of traditional tank water heaters.
  3. This increases their efficiency from 24 percent to 34 percent, regardless of where they work.
  4. This was proven by the Department of Energy of the United States.

They also require less area to operate and have a lower overall maintenance cost.Because of this, it is important to understand why, when, and how to flush out the tank-less water heater, as well if it is preferable to use electric or gas water heaters.The most significant advantage of utilizing a typical tank water heater is that it may save up to 50% on energy costs.As a result, keeping your tankless water heater in good operating order is critical to ensuring its longevity and the ability to flush it on a regular basis.It is required to clear silt and mineral formation that may have formed on the heater’s heating element.Allow us to take you through the entire procedure in order to offer you a better understanding.

See also:  How To Wire A 220V Hot Water Heater

Tank-less Water Heaters and Scale Build-up

  1. Everyone who has tank-less water heaters in their homes understands how important it is to clean the water heaters on a regular basis or at least once a month to eliminate sediments.
  2. The use of tank-less models eliminates the possibility of a buildup explosion, but they can result in increased costs; however, this is not the case with standard tank models.
  3. Tankless water heaters are comprised of heat exchangers, which are very susceptible to scale buildup.
  4. When limescale accumulates in the unit, it is forced to work harder to generate hot water, resulting in a shorter unit life and a significant rise in power expenditures for the homeowner.

As a result, lime accumulation is not covered by the majority of warranties.The usage of electric tank-less water heaters or gas tank-less water heaters is entirely up to you; there are many different options available for you to choose.They are available in sizes that are 80 percent smaller than standard water heaters, and they have a sleek appearance.

When you Should Flush a Tank-less Water Heater

  1. It would be beneficial if you rinsed out your water heaters on a regular basis, once a year.
  2. The hardness of the water, on the other hand, is quite important in this regard.
  3. If you have poor water quality in your house, it is preferable for you to cleanse your water heater three times a year to ensure maximum efficiency.
  4. A sediment trap can assist in reducing hard water to a point where it has a moderate value, hence reducing hardness in the water.

Isolation Valves:

It is critical to be familiar with hot water isolation valves.The isolation valve performs the same function as it does when it makes a sound.The isolation valve function allows you to turn off the liquid or gas supply from a segment of the pipeline without turning off the entire supply line at once.You may have a variety of household appliances that feature built-in isolation valves for use in an emergency or for routine maintenance.Furthermore, these valves are available in a variety of forms and customizations, such as rotatory movement valves and linear movement valves, to meet your specific needs.

The installation of these valves in your heaters should be done by experts and specialists, since it is an important safety component in the heater’s operation.They typically charge between $300 and $400 for cleaning a tank-less water heater, depending on the situation.

Using Pumps and Flush Kits:

The use of a submersible pump is one of the most effective methods of flushing a tankless hot water heater.It is not necessary to use a huge amount of water to swing up and draw the sediment out, as is the case with tank heaters.As a result, choosing a high-quality sump pump, such as the 91250 from the superior pump, will lower the cost of flushing a tank-less water heater while also saving you time.You will need a large bucket for flushing because the submersible pump does not have a drainage system, whereas the drainage system is included in the ordinary model pump.The navien tank-less water heater flush kit is another important piece of equipment.

This package includes all of the necessary equipment, including a pump, descaler, bucket, and hoses.

How to Flush Out a Gas Tank-less Water Heater?

You should consult the owner’s handbook of your water heater to ensure that you are following all of the appropriate instructions. Regardless of whether you use a gas water heater or an electric water heater, you should follow a few steps in the proper order.

Step 1: Preparation:

  • Disconnect the heater’s electric source from the mains power.
  • Remove the access panels and use a non-contact voltage tester to check the power supply coming to the terminals
  • then replace the panels.
  • Close and mark the location of the gas supply valve.
  • When you’re finished, find and close the hot water service valve as well as the cold water supply valve to prevent water from entering the unit.
  • Make a note of the hot water pressure relief valve, which is positioned on the hot water line
  • open it to release any pressure that has built up.
  • Connect the hoses from the cold water service port and the hot water service port together.
  • Fill the 5-gallon pump with water using the submersible pump.
  • The pump should be connected to the cold water line.
  • The free end of the hot water line should be placed in the bucket.
  • In a bucket, combine 4 gallons of white vinegar
  • set aside.

Step 2: Flushing:

  • Turn on the water pump and open the hot and cold water service ports
  • if necessary, add more water.
  • It is required to circulate vinegar through the heater for at least one hour in order to eliminate sediment from the device.
  • First, remove the vinegar from the tank and then turn off the pump.
  • The connecting line should be removed, and the cold water supply should be turned off.
  • The cold water shutoff valve should be opened in order to flush away any remaining vinegar from the second hose.
  • Close the cold water valve at this point.
  • Allow water to flow through the second hose as well for drainage purposes.
  • Removing power from the hot water service port
  • Remove the XSD34Y hot water in-line filter as well as the cold water intake filter
  • and
  • Remove any excess sediment residue from the filters by flushing them down the drain.

Step 3: Cleaning:

  • Discard any surplus paneling and filters, then turn on the hot and cold water shut-off valves.
  • Repair and reopen the gas shut-off valves after reconnecting the electrical supply.

The topic of today’s post is ″how to clean out a tank-less water heater.″ Furthermore, if a thin coating of scale is present in them, they perform at their peak efficiency, resulting in an increase in energy expenses of up to 30%.Using these procedures, you may simply flush out a tankless water heater without any difficulty.As a result, following the basic methods for clearing out water heaters can extend the overall life and durability of the appliance.Tankless water heaters, as opposed to tank-based heaters, are a more advantageous technology since they offer customers with a limitless amount of hot water.

How to Flush Out a Tankless Hot Water Heater: FAQs 

How do you flush a tank-less water heater?

We recommend that you open the cold and hot isolation valves on the water heater to alleviate the situation.Set the pump in the 5 gallon bucket to circulate the vinegar through the heater; it should be dispersed for 45 minutes after the pump is turned on.Next, close the water heater’s valve and allow the vinegar to drain from the heater via the hoses and into a large bucket.Tankless water heaters are turned blue when they are flushed with vinegar.

Do tankless water heaters need to be flushed?

Yes! Especially if you have hard water in your house, tank-less water heaters should be cleansed at least once a year to eliminate the excess quantity of calcium and other minerals that have built up inside the device.

How much does it cost to flush a tank-less water heater?

Repairs must, without a doubt, be carried out by specialists and experts. The typical cost of cleaning out tankless water heaters is between $150 and $800, with some models costing as much as $600. The minerals and sediments must be flushed out of the system on a regular basis in order to maximize efficiency and lifespan.

Types of Tankless Water Heaters by Fuel

A tankless water heater can be powered by electricity, natural gas, or propane, and there are three types of tankless water heaters currently on the market.Water Heater with No Tank (Electric) This sort of heater is quite affordable, with both the original investment cost and the ongoing operating costs being relatively modest.And, most importantly, power is readily available in your residence.It is possible, however, that you may be required to install large electric wires in your home.More information about these electric heaters may be found here.

Water Heater with No Tank Powered by Natural Gas Natural gas heaters have a relatively low cost, however the burning of natural gas adds significantly to the global warming impact.Apart from that, they require regular maintenance.Additionally, you may require additional pipes as well as suitable venting for this heater.

Tankless water heater powered by propane Tankless water heaters fueled by propane are ecologically beneficial, however if you don’t want to utilize the pipes, you may require a propane fuel tank to store the propane fuel.Once again, the installation and operating costs of this heater are less expensive than those of a gas heater.


To conclude the discussion on how to flush a tankless water heater, I will state that it is, indeed, a difficult operation that must be completed in order to achieve the highest possible efficiency and productivity.Tankless water heaters are the most energy efficient since they heat water on demand rather than storing it in tanks, resulting in significant energy savings.Like a result, just as with other household appliances, if you use the proper equipment and procedures, your tankless water heater will operate more effectively, requiring less maintenance and repair in the future.Your tankless water heater will function properly if you follow the procedures and precautions outlined above.More information may be found at: How to Increase Water Pressure From a Rain Barrel.

Easy Maintenance Tips for Tankless Water Heaters w/Photos

A little ‘how-to’ information may go a long way toward ensuring that your tankless water heaters operate at peak efficiency.As a result, not only will you save money on plumbing expenses, but you will also extend the life of your tankless water heater.You may be asking yourself right now, ‘what are some tips for keeping my tankless water heater in good working order?’ Is it necessary to do periodic maintenance on tankless water heaters?Tankless water heaters, like any other type of water heater, require periodic maintenance.When descaling a tankless water heater, it is necessary to remove limescale and other mineral deposits from the burner system located within the tankless water heater itself.

Because of hard water or the amount of hot water your household consumes, you should anticipate to do this once a year at the most.This is something that families of 1-2 persons may undertake once every 2-3 years.It is recommended that you perform this once every 3-5 years if your water is soft or if you have a water softening system installed.

Do you require the services of a Licensed Plumber?We can assist you!In your location, you may get a free estimate from plumbers that are top-rated, vetted, and licensed.It is feasible to service and clean a tankless water heater without the assistance of a professional.Let’s take a closer look at this in further depth further down the page.

  1. Step-by-step instructions will be provided to make it simple to understand how to remove limescale and other mineral deposits from your plumbing system.
  2. We’ll also talk about how often you should maintain your water heater and whether or not a tankless water heater is a good investment in the long run.

Do You Need to Flush Your Tankless Water Heater?

The majority of people are aware that they must flush a tank-style water heater.Most people, on the other hand, are unaware that they should also flush their tankless water heater.Yes, tankless water heaters do require flushing on a regular basis.It is necessary to flush the tankless water heater in order to eliminate limescale accumulation on the burners.Typically, flushing is required every 2 to 3 years in the majority of situations.

When flushing maintenance is necessary, tankless water heaters will automatically shut down and display an error code on the display.Minerals are transported by the water supply.The number of minerals present in the water supply has an impact on the hardness of the water in the tap.

The amount of minerals in the water determines how hard the water is.As the water warms, the sediment separates from the water in the same way as it does in a tank-style water heater.Tankless water heaters, on the other hand, do not have a tank for the silt to settle in.The silt eventually collects on the burners within the tankless unit as well as on the aerators on your faucets.This silt jams aerators, resulting in a reduction in water flow.

  1. If you find yourself cleaning your aerators on a regular basis, it may be time to descale your tankless water heater.
  2. For a household of four, you will most likely need to clean your tankless water heater once per year at the very least.
  3. A family of two may probably get away with flushing their tankless water heater every 18 months or so, according to the experts.
  • The only exception is if a water softening system has been installed in the home.
  • Because of the installation of an in-home water softening system, you may be able to get away with cleaning your water heater once every 3-5 years.
  • Now that you’re ready to learn more about how to manage your tankless water heater, let’s get started.

How to Flush and Descale a Tankless Water Heater

It is necessary to do periodic maintenance on a tankless water heater in order for it to operate properly. These instructions will guide you through the process of flushing your tankless water heater in order to clean and remove mineral deposits from the burner system:

Supplies You Will Need:

  • 2-inch clothes washer hoses
  • channel lock pliers
  • 5-gallon bucket
  • 3-gallon bucket of pure white vinegar or descaling solution
  • sump pump

Tankless water heater flushing kit – 32-ounce is available for purchase from My User Instructions for the J.C. Whitlam FLOW32 Flow-Aide System Descaler – Zoeller 42-0007 Floor Sucker Pump – 5-Gallon Bucket – Safe to Use. This practical set comes with a 5-gallon bucket, two hoses, a descaling solution, and a sump pump, among other things.

Directions for Flushing Tankless Water Heaters:

  • Approximate time: 2-3 hours
  • Difficulty Level: Easy

Step 1: Access your tankless water heater connections

The connections under the tankless water heater may be accessed by removing the cover on top of the unit. Some tankless types may not have a cover fitted at the time of purchase.

Step 2: Verify your tankless water heater has a flushing kit installed

If the flushing valves on your tankless water heater are not there, check to see if they have been installed. Stop what you’re doing and call a qualified plumber to install them.

Step 3: turn off the gas supply

Turn off the gas feed to the tankless water heater at the main shutoff valve. It will be necessary to switch the gasoline supply such that it is ″perpendicular″ to the fuel line. It is

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