Lull 944E-42 Service Manual - Manual (Page 463)

8.211 Model 644E-42/944E-42 Rev. 6/04
Hydraulic System
8.13.4 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.
2. Joystick leaking internally.
3. Inoperative accumulator
charging valve “UP” cartridge.
1. Check accumulator gas charge.
Refer to Section 8.13.2, “Pre-
Charging Accumulator.”
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. 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.
2. Inoperative relief valve in
accumulator charge/secondary
function valve. Valve leaking or
has low setting so full pressure
cannot be reached.
3. Inoperative accumulator
charging valve. “UP” cartridge
or valve adjusted too high.
1. Increase engine RPM to see if
pressure rises to high limit.
2. Check relief valve and/or
replace. Refer to Section
8.12.13, “Accumulator Charge/
Secondary Function Valve.”
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.
2. Pump worn or inoperative and
not delivering full flow or
pressure.
1. Remove and clean charge rate
orifice and filter. Contact the
JLG Service Department if
needed.
2. Check pump flow and pressure.
Refer to Section 8.7, “Hydraulic
System Testing.”
4. Accumulator fails to start
charging.
1. Inoperative accumulator
charging valve “EC” cartridge.
2. Pump worn or inoperative and
not delivering full flow or
pressure.
3. Charge rate orifice or filter in
accumulator charge/secondary
function valve partially plugged.
1. Check cartridge and replace as
needed.
2. Increase engine RPM to see if
valve starts charge cycle.
3. Remove and clean charge rate
orifice and filter.