Is the water gurgling in the radiator or is it only partially warm? Then it may be necessary to bleed it. Actually, that's a tip that you only implement at the start of the heating season, right?
Air in the radiator costs valuable heat. According to TÜV Thüringen, this can increase energy costs by up to 15 percent. Therefore, the tip to bleed the heating is often given at the beginning of the heating period in autumn.
But it is also often appropriate during the winter, says Michael Pommer, home improvement trainer at the DIY Academy in Cologne in an interview. Unless you have an automatic vent valve.
If the heater is gurgling, you should bleed it. And again and again. Because if it makes these noises, it is a sign that there is air in the system and the radiators are no longer getting really warm. Then the heating costs can rise.
But you also have to check whether there is enough water in the system. That means you go to the central heating system and check whether the water pressure is right. There is a pressure gauge on the system for this. If the pointer is in the green area, there is usually enough pressure and therefore water. If not, you have to refill.
How much that has to be depends on the heating system and how many floors have to be supplied. Approximately 1.0 to 1.5 bar pressure is expected per projectile.
Among other things, if you switch off the radiator completely, i.e. turn the thermostatic valve to zero. As a result, the heating water gets cold. Water has a special physical property: warm or hot water expands, cold water contracts again. If you turn off several radiators in the system, the amount of water in the system can contract so much that the volume is balanced by air.
Normally the heater has an expansion tank. This is a round steel kettle with a kind of balloon inside. When the water loses volume, this balloon pushes up a little bit of water. However, if the expansion tank is not in order, the heater draws in air. But it is also possible that connections in the system are not tight, which means that air can get into the system.
If the noises occur several times during a heating period and the radiators are not working properly, then you should call a craftsman. So a heating or plumbing specialist who checks the whole system.
And you should always think about whether you are heating properly. This means that the radiator valves should always be slightly open and the thermostats should never be completely switched off. Not even in summer. It doesn't cost any extra energy either.
If the room temperature is usually around 20 degrees during the heating temperature, then when you're away, turn the thermostat down not to zero, but to level two - which stands for about 15, 16 degrees. You shouldn't fall below this room temperature anyway to avoid mold or other damage.