How To Bleed Hot Water Heater

How to Bleed a Hot Water Heater

Home-Diy When you use a hot water heater to heat the water in your home, “bleeding” your tank is essential to ensuring that the system continues to function properly. In addition to removing mineral deposits that settle at the bottom of the tank, bleeding can also assist to improve the heating capacity of the tank. if (sources.length) then this.parentNode.removeChild(sources); then this.onerror = null; this.src = fallback; )(,; )(,; )(,; (//$/, “), ‘/public/images/logo-fallback.png’) (//$/, “), ‘/public/images/logo-fallback.png’) ” loading=”lazy”> ” loading=”lazy”> Keep your hot water heater in excellent operating order by bleeding it on a regular basis.

A bleed should be performed on your tank at least once a year; however, if your hot water heater encounters a lot of sediment accumulation due to hard water, you should do this procedure biannually.

  • Work gloves, safety glasses and newspaper are all recommended. A large bucket (optional), wash towel and bowl are all recommended.


Your hot water heater’s bubbles or gurgling sound suggests that it needs to be bled. If your hot water heater does not instantly fill with water following the bleeding operation, you may need to add extra water until the pressure exceeds the level required by your system. Please refer to your owner’s handbook for instructions on how to obtain the proper pressure once more. This is normally accomplished by gradually increasing the pressure in the water supply line until the desired level is reached.

If you discover that you are unable to finish the procedure or that you require assistance with additional maintenance activities, contact a trained hot water heater expert.


If you want to prevent getting burnt, keep your hands and face away from the drain valve as it is being opened. Additionally, make sure that children and dogs are kept away from the area throughout the bleed-out operation.

  1. Dress in protective clothing and safety eyewear to keep yourself safe from the hot water coming out of your heater. Lay newspapers below the heater’s threaded nozzle (drain valve) to protect your floor, and connect a garden hose to the valve to collect any water that accumulates. Make sure that the hose is running outdoors, or place a large bucket below the hose’s entrance to catch any water that comes out. Turning off your heater is accomplished by pressing the “On/Off” control switch, which is normally situated towards the bottom of your storage tank. Shut down the cold water intake (labeled “cold”) on the water heater. If you have a gas water heater, switch the valve to “Pilot,” and if you have an electric system, turn off the circuit breakers. As a result of these safeguards, the heating components are not adversely impacted during the bleed-out procedure. Close and protect the drain valve opening with a wash towel before turning the valve to the left gently and starting the bleed procedure. When you hear a hissing sound, it means air is escaping, and then turn on the water and let it run until clear. Because of the silt that has been discharged, the water appears milky in hue. Close the drain valve by moving the handle back to the right, and then remove the garden hose from the drain valve opening. Reconnect the cold water supply line, and then turn the gas water heater knob back to the “On” position to complete the process. Re-energize the circuit breakers, if necessary.

The Drip Cap

  • In the event that you utilize a hot water heater to heat the water in your home, “bleeding” your tank can assist guarantee that the system continues to function properly. Don a pair of gloves and a pair of safety goggles to protect your eyes and skin from the hot water coming from your heater. Make sure that the hose is running outdoors, or place a large bucket below the hose’s entrance to catch any water that comes out. To begin bleeding, cover the drain valve hole with a wash towel and slowly turn the valve to the left to open it and start the bleeding process.

How to Bleed a Line on a Water Heater

A hot water heater that has trapped air inside it does not perform at its best efficiency level. To ensure that your water heater continues to perform properly and to minimize the accumulation of minerals and rust inside the tank, it is recommended that you bleed the line on your water heater once every year. Bleeding the line on the water heater eliminates trapped air and mineral deposits that might interfere with the water heater’s capacity to heat the water it is heating. A well-water system in your house should be flushed at least twice, if not more, every year.

It is well-known that well-water systems and pumps are infamous for injecting minerals and air into the hot water heater, causing sediment and air bubbles to build up inside the water heater.


  • Turn off the hot water heater if it is not already off. Locate the switch, which should be at the bottom of the aquarium. Assuming it is an electric tank, you may shut it down by turning off the circuit breaker at the electric service panel for the house. For gas-powered water heaters, turn the gas valve handle so that it is perpendicular to the gas line before shutting off the water heater. Remove the pilot light from the stove as well.


  • Allow about 30 to 45 minutes for the hot water heater to cool before starting. Make contact with the tank’s exterior. You may start the procedure after it has cooled down.


  • Check the drain cock or hose bib on your hot water heater to make sure they are working properly. It is comparable to the faucets located on the exterior of a home, and it is used to connect a garden hose to the faucet on the exterior of the home. In most cases, it may be found at or near the bottom of the hot water heater.


  • Spread a small plastic sheet or a strip of plastic below the hose bib to protect it from the elements. In this way, spills or drips from the hose bib will not get down to the floor near the hot water heater
  • Nonetheless,


  • Attach the hose to the water heater by manually threading it onto the hose bib in a clockwise direction. If you want to make sure that the hose is completely tightened onto the drain cock, use wide-mouth pliers to do so.


  • Drain the tub by running the hose outdoors via a window or into the tub itself. Make certain that you are using a garden hose that does not have any leaks in it.


  • Open the valve on the water tank’s hose bib, which is located at the top of the tank. Allow the tank to empty completely. If you hear hissing or spitting at the end of the hose, replace the hose. This shows that there is air within the tank.


Keep an eye on the water that comes out of the hose and take note of its color. The water should have a reddish appearance at the beginning of the process. During the process of filling the tank with cold water, it flushes out the tank and flushes the system.

Allow the water to run continuously until the tank is completely flushed. The drain cock valve on the tank should be turned off once it has been filled with clean, cold water. It is safe to switch on the hot water heater again after the tank is fully stocked.

Things You Will Need

  • Water hose, small plastic tarp, wide-mouth pliers, gloves, and goggles are all required.


Using a bucket to empty the hot water heater is not a recommended method. As the bucket fills, the hose bib must be switched on and off several times, which is a time-consuming process that can bring air back into the tank. The best approach is to drain the tank using a garden hose in order to safeguard yourself and your home. Despite the fact that you can drain the tank by turning off the cold-water inlet atop the hot water heater, you run a greater risk of introducing air into your plumbing lines and hot water heater once the tank has been completely drained.

Leaving the cold-water intake turned on while the hot water heater is turned off provides a dual function.

It does this while flushing the system clean.

This prevents air from becoming trapped within the tank when the hose bib is turned off while cold water is flushing the system.

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  1. When it comes to draining the hot water tank, proceed with caution. If you don’t let the hot water from the tank cool down completely, it might cause scalds or burns.

How to Purge Air From a Hot Water Heating System

Photograph courtesy of Jupiterimages/Comstock/Getty Images A hot water heating system is one of the technologies that may be utilized to heat a home. Essentially, this sort of system involves running hot water-filled pipes from your boiler throughout the remainder of your home. Baseboards along the floor or radiators are used to disperse the heat throughout the room. As the water cools, it is returned to the boiler where it will be warmed once more. Occasionally, air will get into the heating system, causing noises such as bubbling or gurgling.

To resolve this issue, you should flush your heating system with water.

Step 1

Turn off your boiler and make a note of the water pressure you were experiencing.

Step 2

Ascertain that the boiler’s self-feeding water valve is linked to the boiler so that water is available to the boiler.

Step 3

Close all of the cutoff valves in your home once you have opened all of the valves that supply the various heating zones in your home.

Step 4

Using a small garden hose, connect it to one of the spigots that comes off the return line (which returns water to your boiler so that it may be heated again).

Step 5

Open the self-feeding valve as well as the spigot, and allow the water to drain into a bucket or down a drainpipe to collect. This procedure should be completed with utmost caution since the water will most likely be quite hot.

Step 6

Allow the water to flow out of the hose until you no longer notice any air bubbles in the water.

Step 7

Examine the water pressure to ensure that it does not rise beyond 25 psi; if it does, open the self-feeding valve until the pressure falls below 25 psi.

Step 8

When there are no more air bubbles in the water, turn off the self-feeding valve and close the spigot to which the hose is attached, allowing the water pressure to recover to normal levels.

Step 9

You will need to repeat this process for each zone until you have bled all of them.

Step 10

Once you’ve done bleeding each zone, close all of the zone valves and open all of the shutdown valves to complete the process.

Step 11

Re-test the water pressure to ensure that it is the same as it was before you bled the system, and then re-turn on the boiler.

How to Bleed a Radiator

In most cases, if your hot water heater is not heating up, it is because air has entered the system. Because air is more buoyant than water, it rises to the tops of radiators, where it prevents the hot water from flowing. The solution is simple: radiators are equipped with bleed valves at the top, which allow you to release trapped air.

What You’ll Need to Bleed a Radiator

The tools you’ll need are straightforward. Many bleed valves can be operated with little more than a straightscrewdriver. Make certain, though, that yours is the right size. Using a screwdriver with a slot that is too narrow will cause the slot to become worn to the point where you will be unable to spin the screw and will need to call a plumber. Radiator keys may be required for older radiators. These are available in a variety of sizes, and you may find them in places like old-fashioned hardware stores, home improvement stores, and plumbing supply stores.

Steps for Bleeding a Radiator

  1. Turn off the heat before attempting to access any bleed valves. If the system begins to move water while a bleed valve is open, it has the potential to suck in additional air. One option is to use the emergency shutdown switch (which is normally situated at the top of the basement steps), or simply dial down the temperature on your thermostat (or on both thermostats). It’s a good idea to bleed all of the radiators, not just the one that’s causing problems. To begin, start on the lower floor with the radiator that is the furthest away from the boiler and work your way closer in. Continue in the same manner on the upper floors. Slowly open the screw while holding a bowl or rag under the bleed valve’s spout with one hand. Closing the valve and moving on is recommended if a constant stream of water is coming out (be careful—if the system has been operating, the water will be hot). Air is leaving through the hissing sound you hear. Close and go on to the next radiator when you’ve established a constant stream of water with the valve open.

Simply said, that’s all there is to it. Paint and bleed valves do not go together, as you may have noticed. The hole in the spout may be covered with paint, and the screw can be painted shut with paint. Paint may be removed off the spout using a stiff wire or a small drill bit. It is possible to release the screw by scraping the paint from the edge of the screw. Occasionally, though, you may need to apply a few drops of acetone (nail polish remover) to soften the paint first before proceeding.

How Does Air Get into a Hot Water System?

How can air get into a plumbing system that is sealed off? In certain instances, the air isn’t even air at all. If your pipes are made of a combination of iron, copper, or brass, galvanic corrosion may be causing them to leak hydrogen gas. Alternately, if you have an older pressure relief tank, it may be dependent on a cushion of air to prevent harmful pressure from building up in the heating system. A portion of the air gets dissolved by the cooler water, and when the heating system is activated, the heat pushes the gas out of the solution.

Old steam systems are capable of sucking air into the system.

By ensuring that an air eliminator is placed immediately after the boiler, you may remove or significantly limit the accumulation of air and other gasses in your system.

How to Bleed a Hot Water Heating System

It’s winter, which means that heating problems are inevitable. The presence of air in a hot water heating system is a typical problem.

My Hydronic Hot Water Boiler System was leaking, and this Instructable will describe how I was able to repair and bleed the system. In order to determine whether or not you need to bleed your hydronic heating system, consider the following: There are a few tell-tale signs:

  • You can hear gurgling or other strange sounds coming from the radiator or plumbing
  • A sound that sounds like water draining from the heating pipes
  • And other strange sounds coming from the radiator or plumbing. insufficient heating, such as a radiator or baseboard that isn’t becoming hot enough.

In certain cases, if you have more than one heating zone in your home, you may need to bleed each one independently.

Step 1: Video

In this video, I demonstrate how I bled my hot water system, but I will also explain it in the following phases.

Step 2: Radiator or Hot Water Baseboard

The most common kinds of hot water boiler heating in North America are radiators and hot water baseboards. Additionally, there is in-floor heating, but I am not as familiar with it, so I am unable to remark on it directly. To bleed air from a radiator, a butterfly-shaped screw will be present that may be loosened to allow any built-up air to escape. A baseboard heater is similar in appearance to an electric baseboard heater, with the exception of the fact that it has an electric heating element, plumbing for a copper pipe, and aluminum fins.

Identifying the bleeder screws will be necessary if, for some reason, air seeps into the system and you need to bleed it back out.

If your system is not similar to mine, you will need to have these installed.

The bleeder should preferably be situated at the highest point of the heating system because that is where the air will gather the most effectively.

Step 3: Automatic Bleeder Vs Manual

Exactly as it sounds, the automatic bleeder removes air from the heating system through a passive bleed process. In the case of a large amount of air in the system, it will take some time before it is completely depleted of its contents. Maintain close watch on them and replace them every few years if they begin to deteriorate. In comparison, the manual bleed is significantly less difficult; nevertheless, it does need you to go through the process of blowing out all of the air by opening and closing the valve until water is released.

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On the baseboard heater, you will need to solder in elbows to keep it in place.

Obviously, this is not ideal, but if the air is able to circulate through the system, it will ultimately arrive up to the automatic bleeder if it was fitted inline since there is just enough space in them to gather the air.

I hope this information on how to bleed your heating system was helpful.

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The automatic bleeder does exactly what it says on the tin: it will passively remove air from the heating system. Because a large amount of air has been introduced into the system, the process will take some time before the air has been completely removed. Maintain close watch on them and replace them every few years if they begin to malfunction. In comparison, the manual bleed is significantly less difficult; nevertheless, it does need you to go through the process of blowing out all of the air by opening and closing the valve until water is emitted.

On the baseboard heater, you will need to solder in elbows.

Obviously, this is not ideal, but if the air is able to circulate through the system, eventually it will end up to the automatic bleeder if it was fitted inline since there is just enough space in them to gather the air.

The information provided should be of use to you in selecting your heating system.

Step 1 – Prep Your Boiler

It is necessary to turn off and locate the drainage valve on your boiler before you can begin bleeding it. In most cases, this valve is found at or at the bottom of the boiler, and it looks quite similar to a regular hose valve on the outside. Once you’ve discovered the right valve, gently screw your garden hose into place with your hands to avoid damaging it.

Step 2 – Bleed Your Boiler

Now that you’ve hooked your hose, drop the exhaust end into a large bucket or, if the line is long enough, place the exhaust end outdoors to catch any water. Place several disposable rags just beneath the drainage valve to mop up any leaks that may occur later on. You will now need to crank the boiler’s fill valve, which is positioned above the drainage valve, in a clockwise direction to allow more water to enter the boiler. A successful bleed of your hot water boiler will be evident once water and air bubbles have ceased emerging from the exhaust end of the garden hose that was used.

How to Purge Air From a Hot Water Heating System

There may be a variety of issues with too much air in your hot water heating system and pipe network, which can be quite frustrating for homeowners. One of the most visible issues is a hissing or gurgling sounds; nevertheless, this may be the least of your concerns at this point. What is the reason behind this? Because of the buildup of contaminants in a hot water heating system that has not been recently purged, the system’s capacity to perform its function may become compromised. This might result in decreased circulation across the system’s maze of pipes and individual radiators as a result of the reduced airflow.

Because most hot water systems are closed systems, water is always flowing between the pipes and the boiler, which is referred to as circulating back and forth.

This step is critical for the correct operation of your complete hot water heating system, as is the process of venting individual radiators and draining your boiler.

  • Begin with the radiator that is the furthest away from your hot water heating system’s boiler and work your way inward. Track down and turn off the bleed valves in each individual radiator unit. It is customary for the bleed valve to be situated in one of the upper corners of the radiator unit itself. Select the most appropriate tool for the project. Radiator bleed valves can be opened in one of two ways: manually or automatically. The simplest valves to open are those that have a straight-edge design on their screwdrivers. Some valves, on the other hand, require a square-figure and the usage of a radiator key to operate properly
  • As soon as you’ve opened the valve, you’ll want to place some sort of holding container (such as a cup or bowl) beneath the spout to catch the water. Even though your eventual aim is to purge the system of air, you may notice that trickles of water are coming out of the spout. Fortunately, this is quite typical and should not cause concern. You should continue to crank the valve with your straight-edged screwdriver or radiator key until you only observe water leaking out of the valve. When all that is coming out of the valve is water, it is an indicator that the air has been purged from that particular radiator unit. Now that you’ve successfully purged the air from one radiator unit, it’s time to continue upstream and repeat the process for following radiators that are closer to the boiler of your hot water heating system. Make a second pass over each individual radiator unit once you’ve finished with them all to confirm that just water is flowing out of the valve on the first radiator (then the second radiator, and so on).

It’s safe to assume that you’ve successfully purged the air from your hot water heating system and will be able to enjoy heat this winter season without having to worry about circulation issues or unpleasant gurgling noises in the pipes.

Air in Hot Water Lines? (DO THIS)

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Signs of Air in Hot Water Lines

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What Causes Air in Water Lines?

It’s difficult to give a straightforward response to this since various systems might have very different problems. There are several potential reasons of air in both hot and cold lines, each of which will necessitate a different type of treatment than if you just had air in the hot water supply.

Gravity-Fed and Other Municipal Water

Despite the fact that these systems operate in various ways, the underlying reasons remain the same. A frequent instance of air becoming trapped occurs when the water supply is turned off for maintenance. This problem may be resolved by just running your faucets for a short period of time.

Well-Fed Water

When there is air in your hot water lines, there are three possible explanations. A defective check valve has the potential to be extremely dangerous because it allows contaminants to enter the water supply. If you believe that the check valve is malfunctioning, you should get it examined and replaced as soon as possible. Another component is methane gas, which, while combustible, is a naturally occurring gas that is typically innocuous to the water supply in most cases. Third, the feed line may not be extending far enough into the well water, enabling air to enter the line.

Air in Hot Water Pipes Only

This indicates that you have air in your water heater while the problem appears to be limited to the hot water lines exclusively. When a heater hasn’t been purged in a long time, air and sediment might begin to accumulate. When it comes to well-fed systems, this is especially true, and the trapped air will often be replenished over a period of many hours.

How to Get Air out of Hot Water Lines

Purging the tank is the most effective method of removing unnecessary air from your hot water supply. If you get your water from a well, you should do this at least twice a year, if not more frequently. Cleaning out your tank of excess air is a somewhat different process from a routine clean-out and requires a few additional precautions to ensure that you are not replacing air with even more air throughout the purging process.

  1. Turn off the electricity. With a gas heater, this entails flicking the valve located towards the bottom of the tank to stop the gas supply and turn off the pilot light. Tanks that are powered by electricity can be turned off at the circuit breaker
  2. To avoid drawing air into the tank during the purge, leave the cold water supply turned on and do not turn on any hot water faucets in the home during the purge. Allow the tank to cool for 30 minutes to an hour for safety reasons. Locate the drain faucet, which should be located at the bottom of your tank. As well as placing some plastic or tarp behind it to prevent water from accumulating on the floor
  3. Connect a hose to the line and run it down to the sewer in your basement. Because shutting the tap repeatedly will worsen the situation, you will not want to drain straight into a bucket when purging trapped air from the system. Activate the drain valve and completely empty the tank
  4. As you drain the tank, the cold water will continue to fill it, driving sediment and trapped air out of the tank. It is possible to monitor the sediment levels by placing the hose in a bucket while it is draining and allowing the bucket to settle for a few minutes. Tank drainage occurs when the water flows clean (or when no sediment forms at the bottom of a bucket after several minutes of sitting) and the tank is completely empty. Turn off the drain valve and wait for the tank to fill up. When the tank is completely full, turn on the power and relight the pilot, if you’re using gas.
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How do you bleed a tankless water heater?

Asked in the following category: General The most recent update was on May 21st, 2020. To begin bleeding, cover the drain valve hole with a wash towel and slowly turn the valve to the left to open it and initiate the bleeding procedure. Wait for the hissing sound that indicates that the air has been expelled, and then let the water to flow until it is clear. Open a few of hot- water taps throughout the home to allow any trapped air to escape through the hot- water pipes. Once there are no more airis in the lines, turn off the faucets.

Turn on the gas supply valve, if the water heater is equipped with one, as well as the circuit breaker for it.

Tankless water heaters provide an infinite supply of hot water while taking up less space, posing a lesser danger of leaking, being safer, and having an overall lifespan that is substantially longer on average.

How much does it cost to flush a tankless water heater, and how long does it take?

Because costs vary so much, I can’t give you a specific figure, but you should anticipate to pay between $100 and $200 to have your tankless serviced. What is the best way to remove air from a heating system? Cleaning and Bleeding the Boiler

  1. Place radiator on its highest temperature setting and verify that the boiler begins to circulate water. Shut down the air conditioning or heating system to prevent airflow or water from being forced through the device. By utilizing the valve, it is necessary to switch off the radiator that is nearest to the heating boiler.

How To Drain A Central Heating System Experts wrote this article. It was last updated in January 2022.

Why is it important to know how to drain central heating?

The vast majority of homes rely on a boiler to not only produce hot water, but also to heat the whole building by circulating steam or hot water through pipes and radiators throughout the building’s interior. It is essential to maintain your heating system in order to guarantee that it operates efficiently and that problems do not arise. As a result, you will need to empty your heating system on a regular basis. If this is the case, the cause for the shutdown might be anything from cleaning out sludge to correcting a leak or replacing the radiator.

To properly drain a central heating system, the following article gives a step-by-step tutorial, which includes the following steps:

  • The vast majority of homes rely on a boiler to not only produce hot water, but also to heat the whole building by circulating steam or hot water through pipes and radiators throughout the building’s structure. In order to maintain the efficiency of your heating system and avoid problems, regular maintenance is essential. Because of this, you will have to empty your heating system on a regular basis. A variety of factors can contribute to this, ranging from the removal of sludge to the repair of a leak to the replacement of the radiator. Knowing how to drain a boiler and radiators can help you to maintain your central heating system effective and operating at maximum capacity for your home’s heating needs and demands. Detailed instructions on how to drain a central heating system are provided in the following article, which includes:

How to drain central heating system

It is usually recommended that you turn off your boiler as a precautionary step before proceeding with any work. This will enable potentially scorching water to cool significantly, hence decreasing the likelihood of any discomfort.

Shut off the water intake valve

While you’re hard at work emptying the central heating system, you can be certain that no water will enter the system since you’ve shut off the water intake valve.

Locate the drain-off valve and attach a hosepipe or place a bucket under it

You’ll need to look for the drain-off valve for your central heating system in this area. Attach a hosepipe to it after you’ve completed this step. If you discover that your hosepipe is a little too slack at the drain-off valve, a jubilee clip can be used to tighten it down. This will prevent it from slipping off and splattering filthy water all over your floor and furniture. In addition, make certain that your hosepipe is long enough to reach the exterior to allow for drainage. It is best not to discharge the water into a flowerbed since some of the chemicals that will be dispensed are not suitable for plants.

When the bucket is completely filled with water, turn off the valve for a short period of time, empty the bucket, and restart the process.

Drain the radiators

First, make sure that all of the radiator valves in the house are fully operational. After that, return to the drain-off valve to which you’ve linked the hosepipe or positioned your bucket and turn it to the open position. After a few minutes, the water in your central heating system will begin to drain.

Open the bleed valves to speed up the process

Open the bleed valves on your radiators to accelerate the process of draining the water out of the system. When you do this, you will be able to plainly hear the air being sucked into the system. Keep in mind to keep containers beneath the radiators to prevent water from spilling out.

Complete the drainage process

Close the bleed valves once again when there is no more water flowing out of the hosepipe or filling your bucket, and you are satisfied that all liquid has been released from the system. Following the completion of all of the valves, return to your drain-off valve with the hosepipe attached and close that one as well, as shown.

When removing the hosepipe, take caution because there will most likely be some water remaining in it. That’s all there is to it! You now have the knowledge and expertise to drain a central heating system the next time the situation calls for it!


These suggestions will assist you in keeping your central heating system functioning at peak efficiency, therefore saving you money on repairs in the long term. More information about emptying your central heating system, as well as why it is necessary, may be found in the following sections: Instructions on how to safely drain a radiator without making a mess

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