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™
PP-7
VALVE MANUAL EMERGENCY
Double
Check
Valve
™
FIGURE 6 - PP-7
TRAILER SUPPLY VALVE MANUAL EMERGENCY
™
PP-7
VALVE PARK APPLICATION
Double
Check
Valve
FIGURE 7 - PP-7
™
TRAILER SUPPLY VALVE PARK APPLICATION
OPERATION - AUTOMATIC EXHAUST (NO
OVER RIDE)
If the driver holds the button of the PP-7
air pressure has dropped below the 40 P.S.I. automatic pop
out pressure, the control piston will move into the exhaust
position when control port pressure falls below 20 P.S.I.
4
Park
Control
Valve
To
Parking
Brakes
#1 Service
Reservoir
#2 Service
Reservoir
Park
Control
Valve
To
Parking
Brakes
#1 Service
Reservoir
#2 Service
Reservoir
™
valve in after supply
Supply
Port
Plunger
Inlet & Exhaust
Exhaust Vent
To Tractor
Protection
Control Port
Control
Piston
Supply
Port
Plunger
Inlet & Exhaust
Exhaust Vent
To Tractor
Protection
Control Port
Control
Piston
OPERATION - PARK APPLICATION
During a parking brake application, the park control valve
removes air pressure from the control port of the PP-7
The button of the PP-7
With air pressure removed from the control port of the PP-7
valve, the control piston moves away from the control inlet
and exhaust valve. The inlet valve seats and the exhaust
passage through the control piston is open. Air at the delivery
™
port of the PP-7
valve is exhausted at the exhaust port of
the PP-7
™
valve.
Control Inlet
and Exhaust
Exhaust
Port
Control Inlet
and Exhaust
Exhaust
Port
™
valve remains in.
™
valve.
™
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