ASV PT-70, Service Manual

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6. If your reading is low, remove the cap and loosen
the jam nut on the posi-power adjustment screw
and turn it counter clockwise until it stops then
retighten the jam nut. (figure 17-11)
a) If the screw was already turned completely
out and pressure reads lower than specified,
the posi-power relief valve is faulty and should
be replaced.
b) If you were able to turn the screw out, recheck
posi-power pressure to see if the reading is
now within specification. If it is, the system
should function properly. If it did not improve,
the posi-power relief valve is faulty and should
be replaced.
To Adjust Posi-Power:
1.
Loosen the jam nut and then turn the screw to
adjust for more or less posi-power function.
(figure 17 -11)
a) Turn the screw clockwise to increase function
and limit pump flow during high load condi-
tions. (less likely to stall)
b) Turn counter-clockwise to decrease function
and maximize pump flow during high load con-
ditions. (more likely to stall)
2. Tighten the jam nut while holding the set screw in
place to keep desired setting.
Auxiliary Flow Test
The PT-70 and PT-80 are equipped with both high and
low flow auxiliary circuits. If an auxiliary flow problem is
suspected, the following procedures should be per-
formed.
Note: If an auxiliary circuit problem is suspected, per-
form all pressure test and adjustment procedures as
necessary prior to attempting the perform the flow test
procedure. Most issues will be solved with the pres-
sure test and adjustment procedures, but if a problem
still persists after all pressures are correctly set, pro-
ceed with the flow test.
Note: The charts above give the acceptable ranges for
fluid flow when loaded to the levels indicated. The low
flow values are to be understood as acceptable if with-
in 1 gpm of the specified value. The high flow values
are acceptable if within 2 gpm of the specified value.
To test flow:
1. Attach a flow meter to the quick couplers of the cir-
cuit to be tested. (high or low flow)
2. Start the machine and activate the circuit.
3. Record and compare your readings with those of
the charts above in both directions.
17-6
Rubber Track Loader
17. Hydraulic Pressure & Flow
L o w F lo w A u xilia
20
19
18
17
0
0
5
10
15
20
25
0 psi 1000 psi 2000 psi 2500 psi 3000 psi
S ystem Loa
H ig h F lo w A u xilia
31 31
30
26
0
0
5
10
15
20
25
30
35
0 psi 1000 psi 2000 psi 2500 psi 3000 psi
S ystem Loa
Required Tools
Flow Meter (with variable loading valve)