Lull 944E-42 Service Manual User Manual download pdf (Page 463)

100

101

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.

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