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8 typical errors when bleeding the radiator

How to Correctly Bleed a Radiator
A number of errors can occur when bleeding the radiator Photo: Getty Images/gevende

November 26, 2024, 5:31 pm | Read time: 5 minutes

As soon as the temperature drops outside, the heating is turned up inside. However, if it doesn’t get really warm, this may be caused by air in the radiator. However, mistakes can also be made when bleeding the heating, which must be avoided at all costs.

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To keep your home nice and warm in winter, you should make sure that the heating is working properly. If there is too much air in the radiator, for example, it may not get completely warm and therefore cannot heat the room properly. You don’t need to be a professional to bleed a heating system. It only takes a few simple steps. However, there are a few mistakes that sometimes happen when bleeding the radiator. Read here to find out what these are and how to avoid them.

1st mistake: Failing to bleed the radiator

There are several mistakes that can be made when bleeding the radiator. However, not bleeding it at all is one of them. If there is air in the heating system, only the air is heated instead of the water. This, in turn, means that the radiator does not get completely warm, and therefore, the room cannot be heated properly. You don’t need to be a professional to bleed a heating system – you can bleed the radiator yourself in just five steps.

2nd mistake: Not switching off the circulation pump

Before bleeding, you should also switch off the circulation pump so that all the air can really collect and then escape. Tenants generally don’t have access to the heating system – but that’s not a bad thing because: “Switching off the circulation pump is not absolutely necessary. If the pump is still running, air bubbles are carried along with the water flow and cannot be vented. If the pump is switched off, it is easier to remove the air bubbles ‘completely,'” explains Dr. Matthias Wagnitz from the Central Association of Sanitary, Heating, and Air Conditioning (ZVSHK) to myHOMEBOOK.

3rd mistake: Only turning the radiator halfway on

If you want to bleed the heating system, you shouldn’t make the mistake of only turning the thermostat halfway up. This prevents the system from calming down and collecting enough air to escape later. Instead, the thermostats must be turned up fully to the highest setting.

4th mistake: Starting to vent immediately

If you have the option of switching off the circulation pump, you should not start bleeding immediately afterward. It is recommended that you wait at least 30 minutes. This allows the heating water to cool down a little, as it can be quite hot under certain circumstances. In addition, the air in the radiators can settle before they are bled.

5th mistake: Failing to check the pressure after bleeding

Another mistake to avoid when bleeding the radiator is to ignore the pressure in the heating system. This is because it drops after the air escapes. “When a heating system is bled, air is removed from the pipe network. The heating water flows in from the expansion vessel and replaces this volume. However, the expansion vessel can only replace this to a limited extent. This leads to a drop in the system pressure, which in turn means that new air can enter the heating system in certain situations,” explains the ZVSHK expert. Then, the radiators would gurgle again.

For this reason, according to Wagnitz, the system pressure should be checked after bleeding. As a rule, tenants do not have access to the central heating system. In this case, he recommends that they inform the landlord or janitor.

6th mistake: Incorrect bleeding sequence

Before bleeding, all radiators that need to be bled should be turned up once and then proceed in a specific order. “If all radiators are turned on and the pump is switched off, air bubbles in the heating system can rise more easily to the top, where they can be vented,” says Wagnitz.

For this reason, it makes sense to switch off the pump or the heating, open all the valves, and then vent the radiators in order from bottom to top. “This gives the air bubbles a little more time to rise,” explains the expert.

But if you don’t do it this way, it’s not a bad thing. Then, you might not be able to remove all the air from the system. But tenants can’t go through the whole apartment building. They already benefit if they ventilate their affected radiators.

7th mistake: Incorrectly setting the valve

Some mistakes can also be made with the valve on the radiator when bleeding the radiator. If possible, you should make sure that the valve is set correctly before bleeding. The valve direction can be varied on some models so that the water jet does not spray uncontrollably onto the wall.

In addition, the valve should not be opened too far so that the water does not simply flow out in an uncontrolled manner. When closing the valve, make sure that you do not use too much force, otherwise it will be difficult to open again.

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8th Mistake: Refilling the radiator without authorization

Another typical mistake that the ZVSHK expert warns against when bleeding the radiator is refilling the heating system without having spoken to a specialist company at least once beforehand. “Desalinated or softened water may need to be used. The entire refilling process should be demonstrated once so that you know what to do. In extreme cases, incorrect topping up can lead to a loss of warranty or damage to the heat exchanger,” says Wagnitz.

This article is a machine translation of the original German version of MYHOMEBOOK and has been reviewed for accuracy and quality by a native speaker. For feedback, please contact us at info@petbook.de.

Topics Heat
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