How To Drain Tankless Water Heater

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

Please keep in mind that this content may contain affiliate links. This means that, at no additional cost to you, we may gain a small profit on purchases made via our links. Knowing how to clean a tankless water heatercan assist you in getting the most out of your investment in terms of efficiency and longevity. Consider the following steps in detail, as well as some helpful tools and crucial considerations.

The Importance of Flushing Tankless Models

Tankless water heaters are less expensive and more energy efficient to operate when compared to standard water heaters. They also demand significantly less maintenance and operating area. That is why it is essential to understand first why and when it is necessary, followed by how to flush a tankless water heater, whether it is gas or electric. 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

Anyone who has had a conventional water tank is aware with the necessity of flushing the tank on a regular basis in order to remove sediment. Tankless heaters are not an exception to this rule. Hard water includes minerals that can cause lime scale to build up on the surface of the water. An explosion from the accumulation is less likely with a tankless heater than with a tank model, but it can still result in some expensive complications with a tankless heater. The heat exchanger is particularly susceptible to scale buildup.

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.

How Often Should You Flush a Tankless Water Heater?

It is recommended that your tankless water heater be cleansed once a year to keep it operating at peak performance. However, the hardness of your water plays a role in this, and you may find that flushing twice or three times a year is preferable if your home’s water is of very low quality in this regard. To a certain extent, a sediment trap or a water softener can help with hard water.

Isolation Valves

It is critical that we explain isolation valves before proceeding with the rest of the processes. 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). 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.

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

A submersible pump is one of your greatest friends when it comes to flushing a tankless water heater. Instead of enormous volumes of water to sweep up and remove the sediment from a tank heater, a high-quality pump such as the91250 from Superior Pump can save you hours if not days of manual flushing and will save you money in the long run. 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.

These kits often include everything you’ll need, including a pump, bucket, descaler, and hoses, among other things.

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

Check the owner’s handbook for your water heater, since it may provide specific instructions on how to flush 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. 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. Discover where the gas isolation valve is located and close it. To prevent any water from entering the unit while you are working, locate the hot and cold shut-off valves and close them accordingly: 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
  2. 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. Fill a five-gallon bucket halfway with water and submerge your submersible pump. The cold water pipe should be connected to your pump. Into the bucket, insert the free end of the hot water line
  3. Pour four gallons of undiluted virgin food-grade white vinegar into a pail and set it aside. In addition, Noritz recommends diluting one gallon of CLR with three gallons of water for heavy-duty applications.

Phase 2: Flushing

  1. Make sure that the hot and cold service ports are open and that the pump is running. 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. Turn off the pump and empty the vinegar into a trash can. Close the cold water service port and disconnect the hose that is connected to it. 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. Close the cold water shut-off valve on your faucet. Allow the water to drain completely before disconnecting the second hose. Close the hot water service port on the boiler. Remove the cold water intake filter as well as the hot water inline filter (if applicable). 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. 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. Open your taps to let any water that has accumulated in the heater to drain
  3. Close the shut-off valve for the hot water supply. 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. Disconnect the wires from the heating elements by removing the screws that hold them in place. Extraction of the heating element is accomplished by loosening the hexagonal brass top of the heating element in a counterclockwise manner
  4. Make a visual inspection of the heating components for evidence of damage. A broken element should be replaced as soon as possible. Storage of the heating elements in the cooper chambers of the heater to allow for cleaning of the heating elements

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. Remove the vinegar from the mixture. Replace the heating elements and reattach the cables as necessary. Open the cold water shut-off valve and let the tank to fill up with cold water
  3. Observe the tank for any evidence of leakage (the paper towel test is quite effective in this situation)
  4. To turn off the hot water, turn the shutoff valve. 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. Close the cold water shut-off valve on your faucet. Clean any dirt from the cold water input filter by flushing the filter under a cold water faucet. Replace the filter in a secure manner. Power should be restored at the breaker once you close the access panel

How to Flush Out a Tankless Hot Water Heater

An on-demand hot water heater, as opposed to a tankless hot water heater, warms water on demand rather than holding it in a storage tank, resulting in significant energy savings. Tankless water heater manufacturers recommend that their units be cleansed at least once a year in order to prevent the buildup of calcium and other minerals within the unit – and even more frequently if you have hard water – to ensure that the device operates efficiently. There are certain units that have an indicator that the unit needs to be flushed.


  • Then, at the breaker panel, turn off the electrical circuit that serves the water heater. To turn off the gas to the water heater if it is powered by a gas heater, spin the gas cutoff counterclockwise around the device.


  • Remove the cover plate from the water heater unit using a screwdriver in order to get access to the wiring within the unit. To test the wiring coming into the terminals, place the tip of a non-contact electrical tester against the wires. As long as the tester light is illuminated, keep turning off circuit breakers or the main circuit breaker for the home until checking all cables reveals that no power is being delivered to the system. Remove the cover plate and replace it.


  • The water supply valve that supplies cold water to the water heater should be turned off. Turn off the main hot-water valve, which is responsible for delivering hot water to the local fixture or many fixtures across the home.


  • Using a 6-foot garden hose, connect the output of a pond pump or sump pump to one end of the hose and the other end of the hose to a cold-water isolation valve. Connect a second garden hose to the hot-water isolation valve to complete the installation. An adjustable wrench should be used to tighten the garden hose couplers.


  • Fill a 5-gallon bucket halfway with water and add the pump and open end of the second hose. Fill the bucket halfway with 5 gallons of freshly harvested, pure white vinegar.


  • Start by opening the hot and cold isolation valves on the water heater, and then turning on the pump in the 5-gallon bucket to circulate the vinegar through the heater.


  • Allow the pump to circulate for 45 minutes, then switch off the pump and allow the vinegar to drain from the water heater via the hoses into a pail (see illustration). Close the cold-water isolation valve to prevent ice formation.


  • Remove the vinegar from the bucket and insert the open-ended hose back into the bucket to complete the process. Turn on the cold-water supply valve and allow the water to run into the bucket for five minutes while the valve is open. Close the cold-water supply valve and detach the garden hoses from the inlet valves to prevent them from bursting.


  • Turn off the hot-water isolation valve if it is still on. Remove the inlet filter screen from the water heater according to the instructions in the owner’s handbook, then rinse the screen to remove any sediment. Reinstall the screen if necessary.


  • The hot-water supply valve should be turned on first, followed by the cold-water supply valve. Open a few of hot-water faucets throughout the home to bleed any air out of the hot-water pipes before starting the project. Once there is no more air in the lines, turn off the faucets.


Ensure there are no leaks in the water heater’s connections by visually inspecting them. Turn on the gas supply valve, if the water heater is equipped with one, as well as the circuit breaker for it. Check to see whether there is hot water coming out of the faucets.

Things You Will Need

  • To make sure that there are no leaks in the water heater, inspect the connections. Install a circuit breaker for the water heater and activate the gas supply valve if it is fitted. Check to see whether the faucets are producing hot water.


  1. It is not recommended to cleanse the water heater without first shutting off the electricity and the gas (if it is a gas heater), as this might cause harm to the appliance. As a precaution, always open the unit and use a non-contact electrical tester to ensure that all power sources have been disconnected before proceeding with the system flushing. It is possible that the device will be damaged if all power sources are not turned off before flushing.

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.
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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.

6. Twist the purge port valves so that they are perpendicular to the positions of the cold and hot valves, and then close them. 7. 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.

  • Given that the majority of your home’s drinking and bathing water is most likely routed through your tankless water heater, employing chemical cleaning solutions might be highly hazardous to your health.

8. To complete the flushing and draining operation, according to the directions provided in your manufacturer’s handbook. 9: When the flushing operation is finished, shut the purge port valves by twisting the T-shaped handles. 10. Disconnect and remove the hosing wires from each of the valves in the sequence listed. 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 or damage the rubber sealing discs that are contained within the caps, though.

12. Refer to your water heater’s owner’s handbook for specific advice on how to properly restart the unit.

  • If this is the case, you may need to rotate and open the cold and hot water valves so that they are parallel to one other and the main valve’s position.

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). It might take up to 2 or 3 minutes for all of the air pockets to be expelled from the system.

How to Flush a Tankless Water Heater

As a rule of thumb, you should clean your tankless water heater once a year (or more frequently if you have hard water or bad water quality). Not only does this remove calcium and other hard water mineral buildups, but it also has the potential to boost the efficiency and durability of the system. Using this method, you will be able to correctly flush a tankless water heater in a short amount of time while maintaining safety standards.

Gather Plumbing Supplies

For example, these are some of the items you will need to accomplish a tankless water heater flushing project:

  • Tools: a screwdriver, an adjustable wrench, and needle nose pliers are all recommended. Hose: Approximately 6 feet of washing machine hose is required. Electrical Tester: A voltage tester that does not make contact with the circuit. You’ll need a submersible pump for this project. A 5-gallon container to collect any extra water is provided. Vinegar (four gallons): virgin, food-grade vinegar or commercial deliming solution

Preparing to Flush a Tankless Water Heater

  1. Turn off the gas feed to your tankless water heater if it is powered by gas. Disconnect electrical power from electric water heaters by turning off the appliance and turning off the circuit breaker for the circuit
  2. Make use of the non-contact electrical tester to ensure that there is no electrical current flowing into the device after opening the access panel Next, find the shut-off valves for the hot and cold water. These should be closed in order to prevent water from entering the water heater. A pressure relief valve is installed on the hot water supply pipe. Using caution, open it to release any pressure that has built up
  3. Avoid contact with boiling water. You may now connect hoses to both the cold-water port and the hot-water port on the faucet. Place the submersible pump in the five-gallon bucket and fill it with water. Next, connect the cold-water line to the pump and insert the other end of the hot-water hose into the bucket to complete the installation. Fill the bucket halfway with the white vinegar that you’ve set aside earlier.

Flushing Your Tankless Water Heater

  1. When you’re ready to start flushing, open both the hot and cold water ports on the faucet, switch on the pump, and let the vinegar circulate for roughly an hour. It is necessary for any mineral scale in the copper lines to break down and for sediment to be cleaned away
  2. Remove the vinegar from the bucket and shut off the cold-water supply port to complete the task. Remove the hose and turn on the cold water shut-off valve to flush any residual vinegar out of the system. Allow it to run for approximately 10 minutes before shutting off the valve.
Once the water finishes draining:
  1. The second hose should be disconnected and closed, and then the cold-water input filter and, if your tankless water heater has one, the hot-water in-line filter should be removed. Using the sink, flush out the sediment. Replace the filters, reinstall the access panel, and reconnect the gas or electricity supply, depending on the unit
  2. Reinstall the access panel.

Note: When you need to flush a tanklesswater heaterthat’s electric, you’ll also need to remove the heating elements.

  1. To do this, unscrew the screws that are holding the wires to them and spin the hexagonal brass top of the heating element in a counterclockwise direction to release it. When you have finished examining the heating components for damage, place them in the copper chambers and let them soak in vinegar for 90 minutes to two hours
  2. Afterward, drain the vinegar out of the system and reconnect the heating elements and cables
  3. Start by turning on a couple hot water faucets and letting them run for about five minutes to flush the system of vinegar and air pockets
  4. Then switch off the water shut-off valves. Prior to removing/cleaning the cold-water input filter, turn off all faucets and shut off the cold-water supply valve. Replacing the filter, closing the access panel, and re-energizing the unit are all recommended.

Contact Home X PlumbingRooter

If you want assistance when flushing a tankless water heater, we are available to assist you. We’re also known for our water heater repair services in Anaheim and throughout Southern California. To make a service request, please contact us through the online or by phone at 714-515-7588.

How to Flush a Tankless Water Heater and Clean the Air Intake Filter

Water heaters that do not have tanks will accumulate calcium and debris on the heating components and filters within the unit. It’s critical to cleanse your system with food-grade white vinegar at least once every 12 to 18 months to keep it running smoothly. The performance and life of your water heater will be extended if you do this straightforward maintenance. This is also a good opportunity to remove and clean the air filter inside the tankless water heater while you’re conducting your regular cleaning.

However, this procedure may be used to any tankless water heater so long as you can identify the necessary components on your machine.

Step 1: Gather Your Materials

You should note that the knobs under your tankless water heater are color coded for your convenience. These levers are responsible for turning off the water and gas to your tankless water heater. If the levers are parallel to the pipe, it implies it is turned on, and if they are perpendicular, it means it is turned off. Make sure they are all perpendicular to the pipes before turning them on.

As a result, the gas (yellow handle on the right side linked to the silver pipes), the central yellow handle, the cold water input (blue), and the hot water outflow will all be turned off (red). During this time, you can also unplug your unit from the power outlet if necessary.

Step 3: Unscrew the Cold Water Service Valve

A service valve is located just above the red and blue levers. The service valve can now be opened once the levers have been rotated such that they are perpendicular to the pipe and the water has been turned off to the tankless hot water heater. But first, gather your stuff and get ready to start. Please keep in mind that there is an external pump that is hooked to the wall near the ground level. The electronic components of the gadget are visible via the vents located at the top of the device.

  1. Make sure you have a bucket ready to capture any excess water that may come out of the faucet.
  2. Even though it is a small amount, you do not want it on your garage floor.
  3. Make sure one end of the hose is inserted into the bucket so that when you remove the service valve cap, you may try to plug it into the opening fast and divert part of the water into the bucket.
  4. Our water heater is only set to 120 degrees Fahrenheit, which I believe to be the case.
  5. The water that comes out of the hot water service valve should not be too hot if you have been taking hot showers, using the dishwasher, and running the washing machine just before doing this.
  6. If the water is hot, you may want to unscrew the service valve carefully so that you don’t burn yourself while doing so.
  7. It occurred to me at that point that the water was not hot, but rather warm, so I completed unscrewing the service valve, plugged in the hose, and allowed the water to drain into a pail.

Step 4: Setup Your Vinegar and Pump

The hoses you used to connect to the service valves in the previous step should be ready to use for this step by now assuming you did so in the previous step. Make sure you empty your 5-gallon bucket of any water that has accumulated in it from the service valves. Approximately 4 gallons of food-grade white vinegar should be added to the bucket. I purchased a generic brand from Safeway, and the total cost for four gallons was $16. Attach the line that connects to the cold water (blue) service valve to the sump pump’s top outlet.

  1. Do not connect the pump at this time.
  2. Because there is no on/off button, it will automatically turn on as soon as you connect it into a wall outlet.
  3. It is not necessary to screw it into the pump; instead, it should be put loosely in the vinegar bucket.
  4. Connect the pump to the electrical outlet as soon as possible.

At the very least, you’ll keep it like way for at least 60 to 90 minutes. The handbook says 45 minutes, but I assumed because it had been so long, I’d simply leave it on for a little longer.

Step 5: Cleaning the Air Intake Filter

Additionally, while the vinegar is being circulated, you should wipe out the air intake filter. If you’ve been noticing an error message on your screen that says “027,” you’re not alone. This indicates that you should clean the air intake filter. The tankless water heater’s air intake filter is situated within the tankless water heater. Don’t worry, it’s not difficult to get to, but you must first remove the tankless water heater face plate before you can get to it. A total of four screws hold it all together.

  1. It is necessary to first remove all of the screws from the face plate before lifting upwards and releasing the hook that connects the top of the face plate to the top of the tankless water heater frame.
  2. Then you’ll want to look for the single screw that holds the air intake filter in place.
  3. As soon as you have unscrewed the one screw that holds the air filter, pull the whole thing slightly towards you and then slant it slightly so that it will slide over the motor, and you have successfully removed the air filter.
  4. Afterwards, I just strolled over to my water spout outside my garage and ran it on full blast, thoroughly rinsing the filter.
  5. Replacing the tankless water heater face plate and allowing the pump to continue to operate for the remaining 60-90 minutes is recommended.
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Step 6: Rinse Your Tanless Water Heater After the Vinegar Treatment

Now that the vinegar has been pumped through the tankless water heater for 60-90 minutes, it’s time to rinse the vinegar out of the tankless water heater. Remove the sump pump from the wall outlet by unplugging it and lifting it out. Allow it to drip into a vinegar bucket and save it aside for later usage. I made the decision to put the vinegar into the toilet rather than on the grass or plants in order to prevent hurting the plants or grass. Now that you have a bucket that is empty, place the bucket back beneath the tankless water heater to keep it there.

  1. Replace the service valve cap with a screwdriver and tighten it.
  2. Allow around 4-5 litres of water to flow through the tankless water heater and out the hot water line into a bucket by releasing the lever controlling the cold water intake.
  3. After everything has been completed, it is necessary to inspect the water filters.
  4. These may be unscrewed with just your fingers if necessary.

After removing the filters, make sure to thoroughly check the area for debris. Reinstall the filters by thoroughly rinsing them with water and screwing them back in.

Step 7: Reattach Everything and Turn It on – Moment of Truth

Following the complete descalement and cleaning of your tankless water heater’s air intake filter, it is time to reassemble everything. Before opening any valves, double-check that all service caps are securely fastened. After you’ve made certain that everything is properly sealed, you may begin opening valves. I’d start with the cold water valve and work my way up from there. You’ll hear the sound of water streaming inside your body. After that, turn on the hot water faucet. After that, the gas and central circulation valves are opened (yellow).

As soon as the display turns on and the machine begins to cycle, you may observe various symbols on the screen.

I hope everything goes as well for you as it did for me.

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With contemporary technology and electric gadgets, science has made life easier for everyone. It is imperative that you are familiar with the operation of these machines. Tank-less heaters are an example of these types of equipment, and you may already have one in your house. 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.

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.

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

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

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.

Tank-less Water Heaters and Scale Build-up

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. 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. Tankless water heaters are comprised of heat exchangers, which are very susceptible to scale buildup. 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.

Water heaters without tanks are available in a variety of configurations, and whether you choose electric or gas tank-less water heaters is entirely up to you.

When you Should Flush a Tank-less Water Heater

It would be beneficial if you rinsed out your water heaters on a regular basis, once a year. The hardness of the water, on the other hand, is quite important in this regard. 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. 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.

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 relieve any pressure that may be present. 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

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.

Apart from that, they require regular maintenance.

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 time-consuming operation that must be completed in order to achieve maximum 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.

More information may be found at: How to Increase Water Pressure From a Rain Barrel

Water Heater Flush: How To Do It Safely and Easily

Your water heater is responsible for delivering all of the necessary hot water to your home when you require it. You may only understand how crucial a piece of equipment is when it is not functioning properly or is backed up in some way. In order to guarantee that your water heater is operating at peak performance, you must ensure that it is thoroughly flushed and cleaned. For the purpose of assisting you in understanding the fundamentals of water heater flushing, we will first discuss why it is so important and how frequently you should perform it.

Why Do You Need to Do a Hot Water Heater Flush?

Water heaters begin to acquire silt and accumulation that is naturally contained in the water supply over lengthy periods of time of usage. Sediment can accumulate in the heater and clump together, resulting in decreased efficiency or damage to the device, depending on the circumstances. When it comes to water heaters in Phoenix, where the water is extremely sediment-rich, this is a regular occurrence. When you flush out your heater, you are preventing excessive sediment building and ensuring that you are able to use the unit more efficiently while experiencing less fear about failure.

Water Heater Flush Cost

As you’ll see, a water heater flush is really inexpensive when you consider that it can be completed in a matter of minutes by following a few simple procedures.

How Frequently Should You Do a Hot Water Heater Flush?

If you consider how important your water heater is, you should not put off cleansing your system for an extended period of time. Every water heater has a varied lifespan, but making sure you clean out your water heater on a regular basis can help it last as long as it was designed to. A flushing of your heater should be done every couple years or so, on average. In order to guarantee the optimum performance from your unit, flushing it once a year is recommended, and the following instructions will demonstrate how simple it is to do.

See also:  How To Filter Water Using Charcoal, Sand And Gravel

Steps for Performing a Water Heater Cleanout/Flush

Your heater, like any other item in your home, will require some level of electrical power to operate properly. Depending on your unit, you may only need to complete one of these procedures during a water heater flush, or you may need to complete all of them. By turning off your gas, you can assure that the machine is not getting any gas and will not overheat or leak as a result. In most cases, turning off the electricity to your unit may be accomplished through your circuit breaker, which should include a switch labeled for the heater.

As you work on the equipment, this will help to avoid any electrical problems from developing. Keeping this step in mind will help to provide a safe working environment for whoever is responsible for finishing the flush.

Open a Hot Water Faucet

This is accomplished by tricking your system into believing it is required to be running, which requires you to open a hot water tap in your home. Despite the fact that water will flow out, it will not be heated at the time of the process. In addition, this procedure is critical because it prevents a vacuum from accumulating in the pipes, which might result in the formation of undesired air bubbles in your water system.

Turn Off the Cold Water Valve

Your water heater will have a supply valve that will connect to the unit and be used to feed cold water to the unit. You will want to turn off this valve while you are completing the flush. It should be positioned on or near your unit, and it will usually be towards the top of the unit’s interior. It will have the appearance of a typical faucet valve, with the possibility of being dyed blue to indicate cold water. It is important to turn this valve off during the flush process to avoid water running into the unit, which would make the whole procedure a lot messier.

Connect a Hose to the Heater

Find the location of your spigot as the next step. This will be located at the bottom of the unit and will seem to be a standard hose faucet in appearance. You may want to set a bucket below this before proceeding with the rest of the project because it may begin to drip as soon as the lid is removed. It is necessary to locate a garden hose that can be screwed onto this spigot since this is the most convenient method of draining the system. If your water heater is located higher up in your home, gravity should be able to facilitate the flow of water.

Make certain that the hose’s end is placed in some form of pail or containment area to prevent it from spilling everywhere.

Water Heater Flush for Sediment: Drain the Tank

It is at this point that you may begin draining the unit by turning the faucet to which the hose has been connected. It is possible to see the circumstances that your heater may be encountering when the water drains out of the tank during this period of time. If the water is largely clear and typical in appearance, it is likely that your water heater is in good working order. Water that is deeper in color and that contains silt, on the other hand, might be a much greater problem. The inside of the tank might be in far worse shape than you can remedy with a simple water heater flush for sediment if you are emptying the tank and a large amount of solid material is coming out of the tank.

This step will be skipped if you are flushing a tankless electric water heater, which is the most common scenario.

Flush the System

Now that the water has been removed from the system, you will begin the process of flushing the unit. Keep in mind that you already switched off the cold-water spigot. This is what you will be turning back on in order to allow the new water to clean out the system properly. It is recommended that you drain the old bucket and thoroughly inspect it for sediment before refilling it with the fresh cleansed water. Remove the tank’s fill valve and flush it for a few minutes until the water pouring out seems clean and typical.

This will signal that the system has been completely cleansed and that the procedure is nearly completed. Always remember to switch off the cold-water supply before unhooking the hose and removing the bucket from the sink.

Reactivate Power and Gas

Now that the flushing has been completed, it is time to clean up. The first step is to cut off the drain to which the hose was attached in order to prevent any water from escaping through it. Also, remember to turn off the hot water tap in your house that you opened at the beginning of this process as well. Replace the cold water supply valve and let the tank to re-fill with cold water. When your tank is full, you’ll want to open the pressure valve on the tank to allow the air to leave for the machine to function properly.

Finally, re-start the gas and water lines heading to the storage tank.


Congratulations! This means that you have done all of the necessary procedures to cleanse your water heater in a reasonably short period of time. Now that you have a better understanding of the procedure, you will be better prepared the next time your heater requires flushing. The time spent flushing your heater will guarantee that it operates at peak performance and that it serves you for many years to come. If you enjoy what you’re reading, you may be interested in reading more of our posts, such as ” Choosing an HVAC Company in Maricopa ” and ” Must-See Historical Sites in Scottsdale ”

Frequently Asked Questions

It is recommended that you flush your water heater at least once a year, especially if you reside in a region with hard water and do not have a water softener. If your softener is in good working order, you can get away with flushing it once every couple of years, but flushing it more regularly won’t hurt.

How much does it cost to flush a water heater?

If you’re not sure in your ability to complete the task yourself, plan to pay around $100. When you consider how detrimental sediment may be to your water heater, this is a relatively insignificant expenditure.

What happens if you don’t flush your water heater?

If you fail to clean your water heater on a regular basis, sediment can accumulate in the tank and cause problems such as clogged drain lines.

How long does it take to flush a water heater?

While your first flush may take a little longer than usual, you’ll soon be able to complete the entire procedure in under an hour and a half.

How to Flush a Tankless Water Heater by Water Heater Experts

The information on how to flush a tankless water heater is provided in the papers that comes with your water heater under the heading “regular maintenance.” Remember? Maintenance and warranty information are included with every item we purchase. The question is, how many of us have truly READ it? And how many of us truly adhere to the recommended maintenance schedule? So, before we get into the specifics of “how to flush a tankless water heater,” we’ll go through some of the reasons why you should really do it.

What is the Purpose of “Flushing” or “Descaling” a Tankless Water Heater?

Tap water includes trace amounts of calcium, magnesium, and other minerals, depending on the source. The higher the mineral concentration of the water, the “harder” the water is. These minerals can build up inside the heat exchanger of a tankless water heater over time.

Initially, the mineral scale will prohibit the water heater from operating at peak performance. If the minerals are not drained out on a regular basis, however, they will actually eat away and destroy the interior of the water heater over the course of time.

What is Used to Flush or Descale Mineral Buildup in a Tankless Water Heater?

Pure white vinegar, much as it is used to flush out or descale mineral accumulation in other water appliances, is the most commonly used to flush out or descale the minerals. The specific directions for each brand and model are slightly different from one another. Commercial descaling products are sometimes recommended by manufacturers. Pure white vinegar, on the other hand, is the safest option. In order to properly flush a tankless water heater, you’ll also need a submersible pump. An hour or so is spent going through the procedure.

However, “flushing kits” are available for purchase on the internet for around $160.

Your Warranty May be Void if Your Tankless Water Heater isn’t Flushed Regularly

Yes, you are correct! Flushing your tankless water heater on a regular basis is an important aspect of routine maintenance. Failure to adhere to the manufacturer’s recommended maintenance procedures will result in the warranty being voided. This is true for the vast majority of tankless water heaters. If the failure of a tankless water heater is caused by a failure to “descale” the mineral buildup on the heat exchanger of your water heater, your warranty may not be valid and your investment may be at risk.

If that’s the case, you’re putting a large amount of money at danger!

So make sure to safeguard your warranty as well as your investment!

Flush a Tankless Water Heater at Least Once a Year

At the very least, it is necessary to flush a tankless water heater once a year. The reason behind this is as follows: The presence of calcium and other minerals in tap water causes corrosion of the heat exchanger in a water heater. A tankless water heater’s lifespan is reduced as a result of corrosion.

If you Live in Fallbrook, Bonsall, Oceanside, Vista or Temecula Flush Your Tankless Water Heater Twice a Year

The hardness of tap water has an influence on water heaters. A water heater’s corrosion rate increases with the hardness of the water because calcium and mineral scales build up more quickly in hard water. Any measurement of waterhardness more than 180 mg/L is regarded to be the hardest water. Fallbrook has the greatest level of hardness in this area, with a score of 205. Oceanside isn’t far behind with a score of 172, which puts it into the “challenging” level. Vistatap water has a dissolved oxygen concentration of 170 mg/L.

(Soft water has less than 60 mg/L of sodium chloride.) In addition, the hard water in our area is another reason to consider building a whole-house water treatment system or water softening system.

In fact, according to the Department of Energy’s website, “annual maintenance can increase the life of your water heater while also reducing energy use.” Furthermore, water heating is the second most expensive source of energy in our houses, accounting for up to 18 percent of our total energy consumption.

Flushing a Tankless Water Regularly Helps Extend its Life and Reduce Energy Costs

So whatever we can do to increase the efficiency of a water heater while also extending its life saves us money! And the goal of our website is to save you money while also alleviating the worry associated with prospective plumbing problems. As a result, we are known as the most inexpensive plumber in the neighborhood (learn more about the various ways we demonstrate our status as the most economical plumber). Here’s what the heat exchanger of a tankless water heater looks like when minerals accumulate and cause corrosion.

However, this is not the case here.

Because of the corrosion, the water heater began to leak, thereby causing the water heater to die.

How to Flush and Descale a Noritz Brand Tankless Water Heater

For the majority of people, we recommend a Noritz brand hot water heater. There are several models to pick from, and we can assist you in selecting the one that best meets your requirements. Because this is the brand that we install the most frequently, we are specialists at flushing and descaling them. Listed below is a video created by the Noritz maker that explains the flushing procedure. However, this video should only be used as a learning tool. Different models necessitate the use of slightly different processes.

Tankless Water Heater Flushing Best Left to Professionals at Least First Time

Allow us to flush your tankless water heater for you–at the very least the first time it has to be flushed after installation. Keep an eye on us during the flushing procedure. After that, you’ll know whether or not you want to do it yourself the next time around. Consider it a risk-free approach to learn how to cleanse your tankless water heater the proper manner without taking any risks. Flushing and descaling should be completed in a timely manner, which may take around an hour. Although it appears to be straightforward in the video, it does need some planning and technological know-how.

Flushing/descaling instructions for the majority of brands begin with shutting off the electricity and, in some cases, even turning off circuit breakers.

The next step will be to educate yourself on how to properly utilize the equipment.

Check Your Manufacturer’s Website for Specific Tankless Water Heater’s Model for Specific Flushing Directions

We have extensive experience with ALL brands of tank-style and tankless water heaters. In fact, we’ve installed and serviced more different brands and types of water heaters than any other plumber in the region, maybe more than anybody else. As a result, we’ll flush and descale your tank or tankless water heater in the most effective and efficient manner. Sure, there are other movies and websites that provide general information on flushing a tank or tankless water heater, but this one is just for you.

However, it is recommended that you follow the precise instructions provided by your manufacturer. This is something you don’t want to get wrong. It’s a significant financial commitment. You want to enhance its energy efficiency while also ensuring that it lasts as long as possible.

Call US – Experts at Flushing Minerals from tank and tankless water heaters!

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