Operation Under Usual Conditions (Cont)
2-121. FOAM SYSTEM GENERAL INFORMATION.
Do not mix different types or manufacturers brands of
foam agent in foam cells or piping. Mixing of different
foam agents (either type or manufacturer) may cause
deterioration of foam agent, improper proportioning
and poor performance in a fire situation. Mixing of
Class A and Class B foam agents may result in a
chemical reaction which can create globules, which
can clog orifices and cause system failure.
When in foam mode never open TANK FILL and
RE-CIRCULATING LINE valve. This will cause foam
agent to enter water tank. If recirculation is needed
to keep pump cool, open PUMP COOLER valve.
Foam system operation from cab (turret operation)
requires system pressure of at least 200-210 psi
(1,379-1,448 kPa) for proper proportion.
Foam system operation from pump operator's panel
requires system pressure of at least 125-250 psi
(862-1,724 kPa) for proper proportion.