Clapper Valve Position Indicator - Task Force Tips OASIS HYDRANT ASSIST VALVE Instructions For Safe Operation And Maintenance

5.4 CLAPPER VALVE POSITION INDICATOR

The clapper valve automatically controls whether water is supplied to the attack pumper directly from the hydrant (at hydrant
pressure), or from a relaying pumper (at boosted pressure). When water pressure is supplied to the "HYDRANT" port and no boost
pressure is being supplied to the "FROM RELAY PUMP" port, the indicator will show the clapper shutting off the "FROM RELAY
PUMP" port and allowing water to fl ow directly from the "HYDRANT" port to the "TO FIRE" port.
When water is supplied from a relaying pumper to the "FROM RELAY PUMP" port at a pressure in excess of hydrant pressure, the
clapper valve closes an inner port that diverts all hydrant water to the assist pumper through the "TO RELAY PUMP INLET" port,
and allows water to fl ow directly from the "FROM RELAY PUMP" port to the "TO FIRE" port at a boosted pressure.
MODE 2 BOOST
Ball valve indicator showing crank rotated
counterclockwise, shutting off "TO RELAY
PUMP INLET". Clapper indictor showing clapper
shutting off inner port and diverting water from
"HYDRANT" port to "TO RELAY PUMP INLET"
port and allowing water to fl ow from the "FROM
PUMP RELAY" port to the "TO FIRE" port.
©Copyright Task Force Tips, Inc. 2010
MODE 1
Ball valve indicator showing crank rotated
counterclockwise, shutting off "TO RELAY
PUMP INLET". Clapper indictor showing
clapper shutting off "FROM PUMP RELAY"
port and allowing water to fl ow directly from the
"HYDRANT" port to the "TO FIRE" port.
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LIA-420 July 12, 2010 Rev00