Terex ASV SR70 Service & Repair Manual page 132

Flow Troubleshooting
If your readings differ from those listed on the charts,
identify the symptom you are experiencing in the list of
possible problems below and follow the steps to identi-
fy and correct the problem.
Problem 1:
Both high and low flow readings are less than
specified.
Possible causes:
1. Auxiliary relief valve pressure setting incorrectly
(see page 17-3)
2. Quick coupler block pressure release valve stuck in
down (release) position.
3. Auxiliary pump malfunctioning or faulty.
4. Engine RPM too low.
Problem 2:
High flow readings are less than specified (low
flow is within specification).
Possible causes:
1. Low charge pressure.
2. Control valve spool malfunction.
Note: Make sure that the high flow reading is greater
than the low flow reading. If they are equal, the prob-
lem is most likely electrical.
Problem 3:
Flow is within specifications in one direction, but
lower than specified in the other.
Possible causes:
1. Auxiliary line relief valve in need of replacement.
(see page 17-4 for test instructions and figure 17-8
for location)
2. Control valve spool malfunction.
Problem 4:
Low flow readings are less than specified (high
flow is within specification).
To correct:
1. Turn the adjustment screw on the pilot generation
block pressure reducing valve clockwise to increase
the flow within the low flow circuit until correct.
(see page 3-5, view D, item 5 to locate)
Problem 5:
Low flow readings are higher than specified (High
flow is within specification).
To correct:
1. Turn the adjustment screw on the pilot generation
block pressure reducing valve counter clockwise to
decrease the flow within the low flow circuit until
correct. (see page 3-5, view D, item 5 to locate)
Problem 6:
High and low flow functions only work in one
direction.
Possible causes:
1. Wire broken or disconnected at the pilot generation
block.
2. Solenoid coil malfunction. (see page 3-5)
3. Solenoid spool malfunction. (see page 3-5)
4. Faulty auxiliary hydraulic switch.
Problem 7:
Low flow works as intended when using the con-
tinuous switch, but does not work when using the
variable flow thumb switch.
Possible causes:
1. Variable flow fuse blown.
2. Power wire to variable flow switch broken or dis-
connected. (BU-16 see electrical schematic)
3. Variable flow switch malfunction.
4. If the switch works in one direction, but not the
other, check the pressure reducing proportional
valves and the wires that connect them to the
wiring harness for proper condition and function.
(see page 3-5, view B item 6, view D item 4)
17-7
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17. Hydraulic Pressure & Flow