We choose the expansion tank correctly

In the heating system of any house there is a certain amount of coolant. From the course of physics, it is known from school that when heated, liquids increase in volume, expanding at the same time. This additional volume should be somewhere placed, otherwise the system will be something like a homemade bomb. In order to avoid the danger of an explosion, a special expansion tank is used, into which the excess excess liquid forms.

The size of a suitable expansion tank should be selected individually for each individual case. It will depend on the total amount of coolant in a particular system.

In modern double-circuit boilers, this capacity is built into the housing. It is not immediately noticed by the owners, because it is hidden under a metal casing. The volume of the expansion tank in such boilers reaches an average of 12 liters. The manufacturers themselves know the approximate size of the room, on which the device is designed, so they install their expansion tank. It has a certain stock of space for an increasing volume of liquid. The expansion tank for heating, built into the wall-mounted boiler, can be increased or replaced by a larger, roomy model.

Types of devices

1. Previously, the most common model was the expansion tank of an open heating system. The principle of its operation is similar to the action of a pot with a lid or a container with a welded pipe. Surplus water flows through it in the case of heating, and then, when the coolant cools, for example, when the boiler is turned off, it goes back to the system. Often open-type tanks are built in overflow - another pipe at the top. Over it, the excess coolant is removed (usually into the sewer). Often, owners do without the expansion tank at all, setting "overflow" at the highest point of the system. It must be ensured that there is a sufficient supply of water in the pipes. The disadvantage of this model is the corrosion of the tank and the large evaporation of the coolant in contact with air. The advantage of this type of tanks is the simplicity of construction and the low cost of installation.

2. Modern models are equipped with closed-type tanks. Such an expansion tank for heating consists of two cavities. One of them is intended for circulation of the heat-transfer medium, the second contains air or nitrogen. The cavities are separated by a special membrane, which stretches when the volume of the coolant decreases or increases. At the same time, the pressure in the entire system remains practically unchanged. Such an expansion tank has certain advantages - the coolant does not evaporate, it is not necessary to put such a tank at the highest point of the system. The disadvantages of this design are a high price and a large volume, because a half tank holds a gas tank.

To calculate the required optimum volume of the expansion tank, multiply the volume of the coolant by 0.08. So, for a system per 100 liters of coolant, an expansion tank for heating of not less than 8 liters will be needed.