Pack Circuit Dump Valve; Pressure Switch; Pressure Switch Adjustment - Wittke StarLight Maintenance Manual

Part #: 90309
P C
ACK IRCUIT
The pilot operated check valve (dump valve) is fitted into the
pack hydraulic circuit for the purpose of speeding up the return
stroke of the packer.
Pressure in the pilot line during the return stroke opens the
dump valve and allows approximately 50 percent of the oil
exiting the cylinders to go directly to the hydraulic tank. The
dump valve is non-adjustable.
? Note: Symptoms of pack circuit dump valve failure include
poor payloads; slow cycle times; low pressure
readings during the pack cycle.
Location:
The pack circuit dump valve is fitted on to the front header
behind the driver side of the cab, on the street side of the
hydraulic valve.
P
RESSURE
The pressure switch ensures the packer returns to the "home"
position during a pack cycle, when the body is nearing capacity
and the is therefore unable to complete a full sweep.
Note:Symptoms of pressure switch failure include poor
payloads; premature return of packer during pack
cycle; failure of to return during pack cycle.
Location: The pressure switch is fitted on the pack circuit
dump valve.

Pressure Switch Adjustment

Both commercial and residential front loaders are equipped with
a pressure switch set to 2350 psi (S
(S ™).
UPERDUTY
? Note: This procedure must be carried out when the body is
full and the packer fully extended proximity switch is
inoperable due to insufficient packer travel.
To adjust the pressure switch:
1. Check the main pressure and verify that it is correctly set
to 2500 psi.
D V
UMP ALVE
S
WITCH
TARLIGHT
™) or 2600 psi
67