How To Bleed Air From Baseboard Heating System – Proper Way

It’s a common issue that air gets trapped in the pipes of baseboard heating systems. When you hear a loud sound from the pipes, it indicates the problem with successful air passing. In this circumstance, you should keep a clear conception of how to bleed air from baseboard heating system. 

Getting the air out from the baseboard heating system is all about performing some constant steps. If you don’t fix this problem immediately, it’ll affect the desired efficiency. However, you can also bleed baseboard heat without using bleeders. 

The process starts with shutting off the boiler. Then, you need to find the relevant valves and turn on the corresponding zone spigot. You can also bleed baseboard radiators with a key or without a key. To understand the elaborated steps, let’s dive into the main discussion. 

How To Bleed Air From Baseboard Heating System

How Does a Baseboard Heating System Works?

If you’re wondering about the working process of a baseboard heater, there are two options. They’ll both offer the heat you require, but in different ways.

Baseboard Hydronic Heaters

A liquid provides the heat in hydronic heaters. They can be linked to a central boiler throughout a house. In a sealed system, the heat source in the boiler heats the water (or oil). Hot water is sent through tubes to specific rooms to provide baseboard heating. 

The water returns towards the boiler to be warmed when it cools. It functions in the same manner as old-fashioned radiators do.

They do take longer to heat up when compared to convection heaters. It will take a little longer to get to your desired temperature. Stand-alone hydronic baseboard heaters are also available.

Baseboard Electric Heaters

This is the most popular baseboard heater, and it is used to regulate the temperature of individual rooms. A heating element constructed of electric coils is located within each heating unit. 

They function similarly to the heating element inside a toaster. When the switch is flipped on, the coils heat up and dissipate heat around the room.

The thermostat upon that heater or on the wall controls these baseboard heaters. As the air in the room warms, it rises, and colder air is sucked into the bottom of the heater. There will also be heat emitted by the pipes, fins, & housing.

How To Bleed Air From Baseboard Heating System

Here, you’ll know multiple ways on how to bleed air from baseboard heating system. 

Getting the air out with a garden hose

The process starts with shutting the boiler off. Then, follow the mentioned steps serially to get rid of the problem.

Step:1- Cut power to the boiler

By cutting power to the boiler, you shut off the boiler to drain the baseboard pipes. It’s all about turning off the corresponding circuit breakers. Unless you do this step successfully, you may face problems while determining the necessary valves. 

Step:2- Determine the shutoff valve

Each zone of a boiler system comes with its zone valve and shut off valve. However, a boiler system comes with multiple zones as well as multiple shutoff valves. You need to close each shutoff valve to pass the stuck air permanently. 

Step:3- Grab a garden hose 

Now, grab a standard garden hose to drain water along with outing air from your baseboard system. You need to attach the garden hose with each spigot perfectly. The other part of the garden hose should be directed to a sink or drain. Stay careful at this point unless you want to be damaged by the draining water.

Step:4- Turn on the corresponding zone spigot

Set the zone valves to manual from auto mode to get water flowing through it. Then, turn on the spigot of each zone. Now, the boiler will be filled with water in several minutes. 

Step:5- Repeat the process

The last move is to drain the residual zones. You need to attach the garden hose with the next zone and repeat the previous steps. Once you’ve performed the steps with all the zones, you’re done. Feel free to turn on the boiler system after finishing everything precisely. 

Bleeding air using a key

Let’s see how to bleed baseboard radiators with a key. 

Step:1- Turn on the water heating system

By turning the thermostat up, you can ensure that the heating system is activated. As the baseboard heating system arrives with multiple zones, there will be multiple thermostats as well as zone valves. So, you need to turn all the thermostats periodically. 

Step:2- Check each radiator

It’s time to wait until each radiator gets warm. You need to ensure at this point that all the manual valves are open. Now, carefully check the baseboard radiators if you find one in cold condition. You should also check if any unit is creating unusual and loud sounds. 

Step:3- Turn the inlet valve counterclockwise

It’s time to turn the inlet valve fully counterclockwise to ensure the water flow. You should use a handle to do this part. It’s recommended to use the square socket valve key or bleeder key here. 

Step:4- Turn the key clockwise

After doing all the steps, you should close the bleeder valve by turning the key clockwise. 

Bleeding air without a key

Let’s see how to bleed baseboard radiators without a key.

Step:1- Ensure to turn on the heating system

Turn on the water heating system and let the radiators be warm. 

Step:2- Check the baseboard radiators

Once you find a radiator is warm enough, check all the radiators like the previous method. If you find any radiator with unusual sound or no heating issue, mark them separately. 

Step:3- Turn on the inlet valves

Now, you should turn on the inlet valves counterclockwise. It’s time to hold a cup next to the bleed valve. The inlet valves of each faulty unit should be turned on immediately. 

Step:4- Go for an alternative of a socket valve key

In case you’re not owning a socket valve key, you can go for a screwdriver. Using needle-nose pliers or hex wrenches is also acceptable. After a while, air won’t come out anymore and it’s time to close the bleeder valve. That’s how you can resolve the air passing issue. 

How to bleed baseboard heat without bleeders 

In this section, you’ll briefly know how to bleed baseboard heat without bleeders. 

  • First, you need to confirm the absence of the bleeder valve in the system. The user may not find it unconsciously as it comes in hidden places sometimes. 
  • Now, you need to locate alternative valves on the baseboard heating system. You should find an automatic valve to do the work more precisely.
  • It’s time to use the pressure reducer valve to purge trapped air. The valve will convert high-pressure liquid into low-pressure liquid. In this way, the hydronic system will be protected. 
  • If this action doesn’t work, you may need to call experts to resolve the problem. 

Why Do I Need to Bleed air from my heating system?

For a boiler to operate correctly, proper air control is required. Not only will your radiators lose heat, but the gas in your system may also cause pressure issues with your boiler.

You can hear bubbling and gurgling in the heating pipes if a hot water heating system produces too much air in the piping. Furthermore, while the heating system is in high power mode, much more air may be in the radiators, heating piping, or baseboards that heat simply does not circulate at all.

So, if you’re a hot water heating system that circulates through baseboard heaters, air will become trapped in the radiators, and you will need to bleed them of this extra air regularly. You may mute bubbling or gurgling noises by bleeding the water baseboard heaters. 

Put a small container beneath the bleeder valve. Pull the valve counterclockwise using needle-nose pliers. Allow the air to escape by leaving the valve open. This is often a do-it-yourself project that will improve the efficiency of your heater.


Now, you’ll get introduced to some common questions about bleeding air from the baseboard heating systems. 

Does baseboard heating need to be bled?

Sometimes, air may get trapped in the radiators of the baseboard heating system. In that case, it’s essential to bleed off the excess air by following any conventional method. Performing this process is important because it may affect the desired efficiency and produce noise.

How do you clear an airlock in a central heating system?

The first responsibility is to turn off the central heating and wait for around 15-20 minutes. When the system is cool enough, place a towel beneath the desired radiator. Now, open the valve by using the radiator key and turning it anti-clockwise. Air will be passed when the irritating sound won’t be anymore. 

Can you hear water running through baseboard heating?

Yes, the boiler system with the baseboard allows you to hear water running through baseboard heating. You can hear the fluid running in case there are air pockets in the discussing system. However, bleeding the excess air from there will turn off the noise.

Do you need to bleed baseboard heaters?

The radiators that feed your apartment’s water heaters must be bled regularly. Otherwise, air will become trapped in the radiators, requiring you to bleed them regularly. This applies to both standing & baseboard radiators. Bleeding radiators ensure that air is eliminated from the system, allowing water to flow correctly through it. Letting your heater run more effectively usually is a do-it-yourself project.

How do I get the air out of my heating system?

Connect the hose to an appropriate drainage site, such as the basement floor drain or an outdoor storm drain. If necessary, walk upstairs and use a wrench or a pair of pliers to open the bleed valves on all heaters. Bleeding your radiator may be a dirty task, so take precautions to preserve your paintwork & carpet. You can also place a small bowl beneath the radiator to collect any water that may seep out.

How does baseboard heat get air?

In a nutshell, the reply is science. Convection is used in baseboard heating. As cooler air enters the room through the doorway, it is routed through a vent to the baseboard heater. A set of metal fins warmed by electricity heat the air inside the baseboard. The heated air is then expelled from the baseboard, and the process is repeated, resulting in a circular movement known as a convection current.

How long does it take to bleed a heating system?

Adjust the radiator to its highest heat setting and ensure the boiler is circulating water. Bleeding a radiator typically takes between 20 and 30 seconds. Based on the scale of the radiator and the amount of air that has to be bled, this can take up to one minute. You may bleed your radiators during any time of year, but the optimal time is around the start of winter.


Bleeding air from the baseboard heating system can be performed in various ways. You need to follow any of the depicted methods to the letter to get the best output. Unless you know how to bleed air from the baseboard heating system, the system will remain faulty. 

Whatever process you follow, you need to turn on the heating system first. Before finding the necessary valves, you should shut off the boiler first. You also have the vent option if you don’t find any bleeder valve on your radiator. 

However, hot water baseboard heaters are an efficient system in comparison to others. If you find a noisy environment inside its pipes, that’s a big problem. And without resolving the issue, you can’t efficiently use the heating system. So, now, we hope you can eradicate this problem easily by following our elaborate methods. 

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