How To Bleed A Home Radiator

A radiator is a device used for heating the air inside your house. There are different kinds of home radiators - steam radiators, baseboard radiators and hot water radiators.

In a steam radiator, a boiler is used to heat water until steam is produced. Since producing steam by letting the water boil, takes time, one cannot expect consistent heating. This system can only produce intermittent heating and cooling for your rooms.

Vented baseboards are used for installing baseboard radiators. The metal fins at the vent openings expand the surface area. Heat is absorbed and radiated from hot water-filled pipes. Accumulation of dust on the metal fins produces an insulating effect. Now, for the air to circulate freely, you should maintain cleanliness.

In a hot water radiator, there is a closed loop with entry and exit points for hot water. Water cools down due to heat emanating from the radiator. Water gets heated again when it goes back into the boiler. 

There are bleed valves on top of each radiator which release the trapped air. You may have faced this problem if you have used a hot water radiator. Letting out the air that is trapped inside the system is called bleeding. It should be done if you want to restore the functioning of the radiator. 

None of us wants cold spots due to trapped air. Finally, the question is how to bleed a radiator?

Here we have given steps for how to bleed a radiator at home. 

1. Make sure you have the correct diagnosis

If your radiator has cool air at the top portion of the radiator, it needs bleeding. But there could be other problems too. So, before going ahead with bleeding, confirm that there are no other problems. Check for other issues listed below:

• If you have more than one radiator in your home and none of them is heating well, then the issue is with the heating system. Either there is an accumulation of sediments within the system or the heater is malfunctioning. This kind of problem would need flushing.

• If you find water accumulating at the bottom of your radiator, it is probably a leak. Turn off the switch and try to tighten or replace the inlet valve nut.

• If there is adequate heating only on the lower floors of your home, then it means that the system doesn’t have enough pressure for hot water to reach the upper floors.

If none of the above issues matches with yours, simple bleeding is probably all you need to do. When you turn on the heat, either the radiator doesn’t feel hot at all or only the bottom region is hot.

2. The radiator key

The bleed valve on top of the radiator is where all the air gets trapped. So, first, you should find the key to unlock the bleed valve. We highly recommend you bleed all the radiators in your home if you have more than one. 

• You would easily find the key to open your radiator valves, in a hardware shop. Keys of different sizes are available for different radiators, so find one that fits yours. 
• If you do not find a key, other simple devices from your toolbox – like a wench or a screwdriver will work fine too. 
• If you are bleeding more than one radiator, keep 2-3 tools to open the valves.

3. Turning off the heat

• If your heating system is active, more air gets into the system. So, turn off the heat.
• Then, give some time to cool.
• After a while, touch and feel the radiator. If parts of it are still hot, wait until it completely cools down.

4. Open the valves of the radiator

• Set both – the inlet and the exit valves of the radiator to ‘open’ position.
• Use the radiator key or any other suitable tool. Place it into the screw in the bleed valve which is mounted on top of the radiator.
• As the air gets released from the radiator, you will hear a hissing sound.
• Once you open the bleed valve, the cold air that was trapped escapes, this gets replaced with the hot water from the heating system.

5. Catch the water droplets

• Water will splutter out of the bleed valve when the trapped air escapes from the radiator.
• Remember to place a bow under the screw or use a cloth to catch the water droplets.

6. Wait until all of the trapped air is released

• After a series of water splutters and air, a steady stream of water will be released from the bleed valve.
• At this point, you can be sure that all of the trapped air has been released from the bleed valve.
• Now, turn the screw clockwise to tighten the valve back into its original position.
• Check for any leaks. 
• If water has splashed around the radiator, wipe it with a cloth.

7. Repeat the above steps for other radiators as well.

• For ensuring proper functioning, it is advised to bleed all the radiators in your home even if you feel that only one of them isn’t working as it should.
• If you regularly bleed the radiators in your home, you will have a well-maintained heating system.
• You may even bleed your radiators annually.

8. Checking the pressure level of your boiler

• After you release excess air from all of your radiators, you may notice that the overall pressure of the heating system of your home has come down.
• If this is left without any action, the pressure may fall further and will not be enough for the hot water to reach the upper floor of your home.
• To set the pressure back to its normal level, top off your boiler with water.
• The pressure required is directly proportional to the height of your home. If you have a taller building, you will need more pressure.
• For a residential building, the usual pressure level maintained is around 12-15 psi.
• Some modern boilers come with automatic fill system, where the pressure is automatically maintained.