One of the important indicators ensuring the optimal functioning of the heating system is pressure.It can be static (affects the bottom of the container and depends on the height and volume) and dynamic (moving occurs when the coolant and the effect on the entire working area of the system).The system operating pressure must be below the maximum acceptable limit.Permissible to consider the upper value at which the operation of the pump and the entire system is still optimal.
Operating pressure in the heating system depends on the volume of coolant, power boiler, pipe diameter, the difference in height in the areas of supply and return water suction.The calculation of the volume of water produced in the autonomous system of conditions: 13 liters per 1 kW boiler output.And for the boiler capacity of 10 kW will be: 10 * 13 = 130 (L).Water meter to help you determine the amount of water present in the system.If the actual value is lower than estimated, it should be increased by adding a heating section.And vice versa.
The limiting pressure is listed in the passport of the boiler and rarely exceeds 1.2 atmospheres.The deviation from the set value leads to equipment failure (if the pressure is below normal), or destruction of the entire system (if the pressure is higher than normal).
For autonomous heating system start (trigger), the pressure is 1.5 atmospheres.As heating (up to 95C) and the expansion of the water (an average of 5%) in the system, this value can reach 2 atmospheres.At this point, the surplus diverted into the coolant expansion tank, designed to compensate for the operating pressure differential.Its capacity is 12% of the total volume of water plus 5% on the expansion of the coolant.For the 10 kW boiler capacity will be: (130 * 12%) * 5% = 16.38 (l).When calculating the initial pressure in the tank to the static pressure difference between the upper and lower levels of added of 0.2 bar.
The centralized heating system closed-under ideal conditions can reach a pressure of 9.5 atmospheres.Due to various leakage it often falls to 5.5 atm.The cause are: depreciation of equipment (pumps, generators, piping), the distance from the boiler house, the remoteness of the apartment from the central riser heating duct, pipe diameter change tenants, during battery replacement (reduced diameter increases the pressure and vice versa).All these figures take into account employees of the boiler to maintain the right (under GOST) pressure.