BWT heating filling block 51955 DN15, installation horizontally with HT connection DN50 below

AQA therm HFB-1717 BA consists of a heating filling block, a Backflow Preventer , Pressure Reducing Valves and shut-off ball valve and is used for the safe and standard-compliant connection of the heating installation to the drinking water supply. The built-in Backflow Preventer the heating installation to be firmly connected to the drinking water installation. This means that the heating system can be easily refilled at any time. Backflow Preventer function: (AQA therm HFB-1717 BA) According to DIN EN 1717, the Backflow Preventer is a safety fitting and prevents contaminated water from being pushed back, flowing back or being sucked back into the supply line, into third-party systems or other system parts. The Backflow Preventer is divided into three chambers (pre-, middle- and rear pressure chamber). If no water is drawn off, the Backflow Preventer is at rest under operating pressure. The inlet and outlet side Check Valves and the drain valve are closed. The Backflow Preventer is in the flow position when water is drawn off. The inlet and outlet side Check Valves are open and the drain valve is closed. If the differential pressure between the inlet pressure and the medium-pressure chamber falls below 1930 , 14 bar, Backflow Preventer into the disconnected position (suck-back). The Check Valves closes and the drain valve opens. Pressure Reducing Valves function (AQA therm HFB-1717 BA) The Pressure Reducing Valves reduces the pressure on the input side (inlet pressure) to the desired pressure on the output side (back pressure). The Pressure Reducing Valves works according to the force comparison principle. The spring force of the control valve counteracts the membrane force the outlet pressure (back pressure) and thus the membrane force, the now greater spring force opens the valve. The outlet pressure increases again until a state of equilibrium between membrane and spring force is reached again. The inlet pressure (primary pressure) has no influence on the control valve in Pressure Reducing Valves . Pressure fluctuations on the inlet side do not affect the outlet pressure (inlet pressure compensation). According to DIN EN 1717, the AQA therm HFB-1717 BA can be permanently connected to the drinking water line using a hose or pipe (KTW approval for the hose required). After completion of the filling process, the shut-off device must be actuated to prevent uncontrolled refilling of the heating system.