Lull 944E-42 Service Manual - Manual (Page 153)

8-37 944E-42
Hydraulic System
8.7.17 Accumulator Charge Troubleshooting
Problem Cause Remedy
1. Accumulator charging cycle
repeats frequently when
accumulator is not normally
being discharged.
1. Incorrect accumulator gas
charge on one or both
accumulators.
1. Check accumulator gas charge.
Refer to Section 8.7.16,
“Checking Pre-Charge.”
2. Joystick leaking internally. 2. Temporarily cap OFF “PIL” port
and hose on accumulator
charge /secondary function
valve to see if problem is
resolved. Troubleshoot joysticks
if it does.
3. Inoperative accumulator
charging valve “UP” cartridge.
3. Check cartridge and replace as
needed.
2. Accumulator starts to charge
but does not reach high limit.
1. Pump worn or inoperative and
not delivering full flow or
pressure.
1. Increase engine RPM to see if
pressure rises to high limit.
2. Inoperative relief valve in
accumulator charge/secondary
function valve. Valve leaking or
has low setting so full pressure
cannot be reached.
2. Check relief valve and/or
replace. Refer to Section 8.7.13,
“Accumulator Charge/
Secondary Function Valve.”
3. Inoperative accumulator
charging valve. “UP” cartridge
or valve adjusted too high.
3. Adjust or replace cartridge as
needed.
3. Accumulator charging time
too long.
1. Charge rate orifice or filter in
accumulator charge/secondary
function valve partially plugged.
1. Remove and clean charge rate
orifice and filter. Contact the
JLG Service Department if
needed.
2. Pump worn or inoperative and
not delivering full flow or
pressure.
2. Check pump flow and pressure.
Refer to Section 8.7.14,
“Accumulators.”
4. Accumulator fails to start
charging.
1. Inoperative accumulator
charging valve “EC” cartridge.
1. Check cartridge and replace as
needed.
2. Pump worn or inoperative and
not delivering full flow or
pressure.
2. Increase engine RPM to see if
valve starts charge cycle.
3. Charge rate orifice or filter in
accumulator charge/secondary
function valve partially plugged.
3. Remove and clean charge rate
orifice and filter.