They are used for household installations and small municipal systems. Traditionally used in radiant heating systems. Diaphragm - non-replaceable, is rigidly fixed on the perimeter of the tank section. In one volume with air, in the other - coolant. The outer surface of the tank is covered with enamel and the inner surface in contact with the liquid - water-resistant epoxy paint. The initial position of the entire volume of the tank is filled with air.
The Amtrol under the influence of the air pressure is pressed to the inner surface of the tank. As the temperature in the fluid volume increases, pressure increases and the coolant enters the expansion tank, pressing Amtrol. At the same time the air in the opposite chamber pot shrinks.
The disadvantage of this design is its inability to replace the Amtrol Fill-Trol if it is the gap or high water permeability. However, in the heating systems in their normal operation, the maximum expansion of the liquid occurs only at the time of launch. In other cases, the pressure varies smoothly, without major shocks and fluctuations. Consequently, in the tanks are quite long. You only need to pre-season heating check the air pressure in the tank. In heating systems it is desirable to control the large amount of air pressure in the expansion vessel with a stationary gauge. The gas in the expansion vessel can shrink only to a certain value, due to security (strength) of the system. In most cases, this threshold is achieved by installing a safety valve set at a certain pressure value. In individual homes, this value usually is 3,5-4 bar.
