How to bleed a radiator
How to bleed a radiator in 5 simple steps. In this “how to bleed a radiator” guide we will demonstrate how to bleed a radiator like a professional. Bleeding a radiator is a simple process and knowing how to do so is essential for every home owner with a wet central heating system.
You are probably looking at this how to bleed a radiator web page because you have a central heating radiator that is not getting very hot. If your radiator requires bleeding then the upper section of the radiator will cooler than the bottom. If the top half is hot and the bottom half is cool then the radiator in question may actually be sludged up.
Many people assume that when we bleed radiators that we are actually allowing trapped air out of the radiator. Whilst this is sometimes the case more often than not it is hydrogen sulphide gas being bled from the radiators particularly in older heating systems. Knowing this one should exercise caution when bleeding radiators. Hydrogen sulphide having a lower specific gravity than air will float and if you are smoking a cigarette at the time of bleeding a radiator you could get a nasty surprise!
The human body harbors vast quantities of bacteria. Don’t panic. It is not all bad bacteria. Central heating systems are also a breeding ground for bacteria. You would think that the high temperatures of the central heating system would kill any bacteria but these “Extremeophiles” are very hardy indeed. Well after all they do eat the metal from within your central heating system. The anaerobic bacteria produce hydrogen sulphide as a waste product and it is this that collects in your radiators. Hydrogen sulphide has the characteristic smell of rotten eggs and is highly explosive. If you are careful and you know how to bleed a radiator you can try a little experiment. We take no responsibility for any injury or damage caused by this experiment. Make sure you are or have a responsible adult with you to supervise this experiment. If you upturn a plastic beaker and hold it over the radiator bleed vent when bleeding the radiator you can collect some hydrogen sulphide gas. If you put a lighted splint into the upturned beaker then there should be a small explosion.
Well enough of the biology lesson lets move forward and explain how to bleed a radiator. You will need a rag and a radiator key.
- First operate your central heating system and allow it to get hot. Identify any radiators that are cool at the top and hot at the bottom. Leave the central heating system on and calling for heat. You may need to turn up your room thermostat.
- Locate the radiator bleed vent. It will look something like this.
- Place a rag in front of the spout and use the radiator key to turn the square radiator bleed nipple slowly anti-clockwise. Under no circumstances completely remove the bleed nipple. It may become lost and you will be stuck holding your finger over a hole until help arrives.
- You will hear a hissing sound as the gases from the radiator escape. As soon as the gases run out then water will follow. When this occurs quickly turn off the bleed nipple in a clockwise direction. The water from the radiator may be hot and dirty so catch any escaping water in a rag.
- Dry off the area with your rag or tissue. Very quickly you should notice that the radiator becomes hot at the top.
Congratulations you have just bled your first radiator!
This concludes our how to bleed a radiator guide