Expansion Tanks in Heating Systems: Essential for Pressure Management

The function of the expansion tank, in its two types, sanitary or for the heating system, is to create a kind of hydraulic spring capable of reducing the increase in water pressure in a circuit that is being heated.

The expansion tank of a boiler is a crucial component of the heating system to which the boiler is connected. Its main task is to compensate for water pressure variations within the heating circuit, caused by temperature variations of the water itself.

Practically speaking, when the water heats up, it tends to expand and occupy more space within the heating circuit. Without a way to compensate for this expansion, the pressure within the circuit would increase, risking damage to the pipes or the boiler itself.

The expansion tank solves this problem by providing additional space within the heating circuit, where excess water can be stored when it expands. Thus, the expansion tank helps to maintain constant pressure within the circuit, regardless of the temperature variations of the water.

The expansion tank can vary in size and shape, depending on the size of the heating system. It generally consists of a tank made of steel or other pressure-resistant material, fitted with an internal membrane that divides the tank into two compartments. One compartment is filled with compressed air, while the other is filled with water.

In summary, the expansion tank of a boiler is an important component of the heating system, allowing for compensation of water pressure variations within the heating circuit, caused by temperature variations. The expansion tank, with its tank and internal membrane, maintains constant pressure in the heating system.

Utility of the Expansion Tank in Heating

The expansion tank in heating is indispensable, and often additional units are added depending on the size of the heating system.

It is the most stressed component and must be kept constantly pressurized. Otherwise, if deflated or damaged, it could compromise the safety valve of the heating system, posing a risk of leaks.

What is the Correct Pressure of the Expansion Tank in Heating?

Manufacturers pre-charge the air chamber to about 1.5 bar, however, this pressure is excessive. The expansion tank in heating should be charged to a pressure of 1.2 bar to function optimally.

Undersized Expansion Tank in Heating

If the square footage of the house or apartment is substantial, the standard 8-liter tank accompanying a common boiler might not be enough. The effects of an inadequate hydraulic spring are seen when, despite a fully functional and inflated expansion tank, there is a pressure difference of more than 1 bar between cold and hot system.

In such cases, an additional expansion tank is added to the heating system.