https://youtu.be/83JuPJC-Is4 If metering valves are not working properly or foam pump stops, the water pressure overcomes the foam pressure and water enters into the manifold. Consequently, a check valve is installed between foam manifold and each metering valve to prevent backflow of water into the foam system.
https://youtu.be/wLQg0KuT2Ec A pressure relief valve is supplied on the foam system and When system is set to the manual switch position, at pressure higher than 250 PSI the relief valve will open and foam flow is returned to the suction side of the pump to protect foam system components from over-pressure conditions. How does the…
https://youtu.be/N2Nlhllwx08 Foam concentrate is pumped from the tank or remote source and discharged through manifold and then, metering valves to the individual ratio flow controllers. Each water discharge, that is dedicated for foam operation is equipped with a ratio flow controller that proportions foam concentrate into the water line. Ratio flow controllers are modified venturi…