Tronair 5JX1 Series Installation and operating instructions

OPERATION & SERVICE MANUAL
For Spare Parts, Operations & Service Manuals or Service Needs
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Tronair, Inc. Phone: [phone] | 800-426-6301
1 Air Cargo Pkwy East Web: www.tronair.com
Swanton, OH 43558 Email: [email protected]
5JX1 Series
5J11, 5J21, 5J31, 5J41
Hydraulic Power Units
06/2023 −Rev. 04

REVISION DATE TEXT AFFECTED
01 12/2017 Original release
02 08/2021 Added section 5.13 Infrequent HPU Use and updated 9.0 Maintenance
03 02/2023 Major revision
04 06/2023 Updated 9.6 Hydraulic Hoses

Model: 5J41
Hydraulic Power Unit
02/2023 | Rev. 03
TABLE OF CONTENTS PAGE
1.0 PRODUCT INFORMATION ..............................................................................................................................................1
1.1 DESCRIPTION................................................................................................................................................1
1.2 MODEL & SERIAL NUMBER ..........................................................................................................................1
1.3 MANUFACTURER...........................................................................................................................................1
1.4 FUNCTION......................................................................................................................................................1
1.5 REQUIREMENTS............................................................................................................................................1
2.0 SAFETY INFORMATION..................................................................................................................................................1
2.1 USAGE AND SAFETY INFORMATION...........................................................................................................1
2.2 EXPLANATION OF WARNING & DANGER SIGNS........................................................................................1
2.3 COMPONENT SAFETY FEATURES ..............................................................................................................2
2.4 FUNCTIONAL SAFETY FEATURES...............................................................................................................2
2.5 PERSONAL PROTECTION EQUIPMENT ......................................................................................................2
2.6 SAFETY GUIDELINES....................................................................................................................................2
2.7 GENERAL COMMENT....................................................................................................................................2
3.0 PREPARATION PRIOR TO FIRST USE ..........................................................................................................................2
3.1 GENERAL .......................................................................................................................................................2
3.2 SERVICING RESERVOIR...............................................................................................................................2
3.3 CONNECTING ELECTRICAL LEADS.............................................................................................................2
4.0 TRAINING.........................................................................................................................................................................3
4.1 TRAINING REQUIREMENTS..........................................................................................................................3
4.2 TRAINING PROGRAM....................................................................................................................................3
4.3 OPERATOR TRAINING ..................................................................................................................................3
5.0 OPERATION.....................................................................................................................................................................3
5.1 OPERATING PARAMETERS..........................................................................................................................3
5.2 NUMERICAL VALUES ....................................................................................................................................3
5.2.1 Fluid.................................................................................................................................................................3
5.2.2 Physical...........................................................................................................................................................4
5.2.3 Hydraulic Pump ...............................................................................................................................................4
5.2.4 Electric Motor...................................................................................................................................................4
5.2.5 Filters...............................................................................................................................................................5
5.2.6 Hand Pump (Option M)....................................................................................................................................5
5.3 LOCATION & LAYOUT OF CONTROLS.........................................................................................................6
5.3.1 Front Panel Controls........................................................................................................................................6
5.3.2 Electrical Control Panel ...................................................................................................................................7
5.3.3 Hydraulic Control Panel...................................................................................................................................8
5.3.4 Rear Panel Controls ........................................................................................................................................9
5.3.5 Hydraulic Pump Controls...............................................................................................................................10
5.3.6 Hand Pump Controls (Option M)....................................................................................................................11
5.3.7 Split System Controls (Option C)...................................................................................................................12
5.3.8 Split System Crossover Check Controls (Option D).......................................................................................13
5.4 START UP PROCEDURES...........................................................................................................................14
5.4.1 Procedure for First Time or Different Electrical Supply ONLY.......................................................................14
5.4.2 Initial Start Up of the HPU..............................................................................................................................14
5.5 PRELIMINARY ADJUSTMENTS FOR OPERATION ....................................................................................14
5.5.1 Flow Control Adjustment................................................................................................................................14
5.5.2 Pressure Control Adjustment.........................................................................................................................15
5.5.3 Reservoir Selector Valve Operation...............................................................................................................15
5.5.4 Bypass Valve Operation................................................................................................................................15
5.6 BLEEDING AIR FROM SYSTEM ..................................................................................................................15
5.6.1 To Easily Purge the Unit of Air.......................................................................................................................16
5.7 SPLIT SYSTEM OPERATION (Option C) .....................................................................................................16
5.7.1 To Operate the Split System..........................................................................................................................16
5.8 SPLIT SYSTEM CROSSOVER CHECK (Option D)......................................................................................16
5.8.1 To Operate the Split System with Crossover Check......................................................................................16
5.9 HAND PUMP OPERATION (Option M).........................................................................................................17
5.9.1 To Operate the Hand Pump...........................................................................................................................17
5.10 SAMPLE VALVE............................................................................................................................................17
5.11 EMERGENCY SHUT DOWN PROCEDURE.................................................................................................17
5.12 DESCRIPTION OF ALARM SYSTEMS.........................................................................................................17
5.12.1 High Fluid Temperature Indicator (Option S).................................................................................................17
5.12.2 Voltage/Phase Monitor Indicator (Options G − J) ..........................................................................................17
5.12.3 High and Low Reservoir Level Indicator (Option L) .......................................................................................17
5.12.4 Clogged Filter Indicator Light (Option R) .......................................................................................................17
5.13 INFREQUENT HPU USE ..............................................................................................................................18

Model: 5J41
Hydraulic Power Unit
02/2023 | Rev. 03
5.13.1 Infrequent HPU Use Start Up Procedure.......................................................................................................18
6.0 PACKAGING AND STORAGE.......................................................................................................................................19
6.1 PACKAGING REQUIREMENTS....................................................................................................................19
6.2 HANDLING....................................................................................................................................................19
6.3 PACKAGING PROTECTION.........................................................................................................................19
6.4 LABELING OF PACKAGING.........................................................................................................................19
6.5 STORAGE COMPATIBILITY.........................................................................................................................19
6.6 STORAGE ENVIRONMENT..........................................................................................................................19
6.7 STORAGE SPACE AND HANDLING FACILITIES........................................................................................19
7.0 TRANSPORTATION.......................................................................................................................................................19
8.0 TROUBLE SHOOTING...................................................................................................................................................20
8.1 HPU WILL NOT START ................................................................................................................................20
8.2 NO FLOW......................................................................................................................................................20
8.3 REDUCED FLOW..........................................................................................................................................21
8.4 NO PRESSURE or REDUCED PRESSURE.................................................................................................21
8.5 FLUID OVERHEATS.....................................................................................................................................21
8.6 HAND PUMP (Option M) IS NOT PUMPING FLUID .....................................................................................21
9.0 MAINTENANCE..............................................................................................................................................................22
9.1 GENERAL .....................................................................................................................................................22
9.2 ELECTRIC MOTOR.......................................................................................................................................22
9.3 HYDRAULIC PUMP.......................................................................................................................................23
9.3.1 Hydraulic Pump Replacement Kits List..........................................................................................................23
9.4 HYDRAULIC FLUID.......................................................................................................................................24
9.5 FILTERS........................................................................................................................................................24
9.5.1 Pressure Filter ...............................................................................................................................................25
9.5.2 Return Filter...................................................................................................................................................26
9.5.3 Hand Pump (Option M) Filter.........................................................................................................................27
9.5.4 Desiccant Air Filter.........................................................................................................................................28
9.6 HYDRAULIC HOSES ....................................................................................................................................29
9.7 INSTRUMENT PANEL ..................................................................................................................................30
9.7.1 Electric Panel.................................................................................................................................................31
9.7.2 Hydraulic Panel..............................................................................................................................................32
9.7.3 Control Block/Flowmeter................................................................................................................................33
9.7.3.a System Pressure Relief Valve .......................................................................................................................34
9.7.3.b Check Valve ..................................................................................................................................................35
9.7.3.c Bypass Valve.................................................................................................................................................36
9.7.4 Flow Control ..................................................................................................................................................37
9.7.5 Pressure Control............................................................................................................................................38
9.8 RESERVOIR ASSEMBLY.............................................................................................................................39
9.9 RETURN MANIFOLD ASSEMBLY................................................................................................................41
9.9.1 Return System Pressure Relief Valve............................................................................................................43
9.10 PRESSURE FILTER ASSEMBLY (Single System).......................................................................................44
9.11 ELECTRICAL COMPONENTS......................................................................................................................45
9.11.1 Electrical Components With 100 ft Input Cord Option....................................................................................49
9.12 HEAT EXCHANGER ASSEMBLY.................................................................................................................52
9.13 EXTERNAL COMPONENTS.........................................................................................................................53
9.14 ADDITIONAL FEATURES.............................................................................................................................54
9.14.1 50 ft (15.24 m) Hoses (Option B)...................................................................................................................54
9.14.2 Split System (Option C).................................................................................................................................55
9.14.3 Crossover Check (Option D)..........................................................................................................................56
9.14.4 Hour Meter (Options E and F) .......................................................................................................................57
9.14.5 Voltage/Phase Monitor (Options G − J).........................................................................................................58
9.14.6 Pyrometer (Option K).....................................................................................................................................59
9.14.7 Electric Reservoir Level (Option L)................................................................................................................60
9.14.8 Hand Pump (Option M)..................................................................................................................................61
9.14.9 Towing Trailer (Option N) ..............................................................................................................................63
9.14.10 Calibration Port (Option Q)............................................................................................................................64
9.14.11 Electric Filter Clogging Indicator (Option R)...................................................................................................65
9.14.12 Electric Over-Temperature (Option S)...........................................................................................................66
9.14.13 Return Back-Pressure with Sight Gauge (Option T) available on model 5J31 Only ......................................67
9.14.13.a Item 16 Sight Glass Assembly Exploded View ..............................................................................................69
9.14.14 Return Sight Gauge (Option U) .....................................................................................................................70
9.14.15 Return Back Pressure (Option V) ..................................................................................................................71
9.15 REPLACEMENT LABELS PARTS LISTS .....................................................................................................72
9.15.1 Base Unit.......................................................................................................................................................72
9.15.2 Fluid Label.....................................................................................................................................................72
9.15.3 Filter Element Kit Labels................................................................................................................................72
9.15.4 Split System (Option C) and Crossover Check (Option D) Labels.................................................................73

Model: 5J41
Hydraulic Power Unit
02/2023 | Rev. 03
9.15.5 Pyrometer (Option K) Label...........................................................................................................................73
9.15.6 Hand Pump (Option M) Labels ......................................................................................................................73
9.15.7 Calibration Port (Option Q) Labels.................................................................................................................73
9.15.8 Back-Pressure Valve with Sight Glass (Option T) Label................................................................................73
10.0 PROVISION OF SPARES...............................................................................................................................................74
10.1 SOURCE OF SPARE PARTS .......................................................................................................................74
10.2 RECOMMENDED SPARE PARTS LISTS.....................................................................................................74
10.2.1 Spare Electrical Parts....................................................................................................................................74
10.2.2 Spare Parts....................................................................................................................................................74
11.0 CALIBRATION OF INSTRUMENTATION ......................................................................................................................75
11.1 SOURCE OF CALIBRATION ........................................................................................................................75
12.0 IN SERVICE SUPPORT..................................................................................................................................................75
13.0 GUARANTEES/LIMITATION OF LIABILITY..................................................................................................................75
14.0 APPENDICES.................................................................................................................................................................75

Model: 5J41
Hydraulic Power Unit
02/2023 | Rev. 03 Page | 1
This product cannot be modified without the written approval of Tronair, Inc. Any modifications done without written approval
voids all warranties and releases Tronair, Inc., it suppliers, distributors, employees, or financial institutions from any liability
from consequences that may occur. Only Tronair OEM replacement parts shall be used.
1.0 PRODUCT INFORMATION
1.1 DESCRIPTION
Hydraulic Power Unit (HPU)
Model Number Fluid Type
5J11 ..............................MIL-PRF-5606
5J21 ..............................MIL-PRF-83282
5J31 ..............................Aviation Phosphate Ester, Type IV and V
5J41 ..............................MIL-PRF-87257
1.2 MODEL & SERIAL NUMBER
Reference nameplate on unit.
1.3 MANUFACTURER
TRONAIR, Inc. Telephone: [phone] or 800-426-6301
1 Air Cargo Pkwy East Fax: [phone]
Swanton, Ohio 43558 USA E-mail: [email protected]
Website: www.tronair.com
1.4 FUNCTION
The Hydraulic Power Unit (HPU) provides a source of clean, pressurized hydraulic fluid for performing required
aircraft maintenance. An electric motor drives a pressure compensated piston pump. Filters are provided on the
pressure and return systems. A bypass (dump) valve allows starting and stopping of the unit under a no-load, safe
condition. The unit may use either the aircraft or on-board HPU reservoir. Cooling is provided for continuous
operation.
1.5 REQUIREMENTS
Adequate electrical power must be provided for proper functioning of the HPU. See the unit nameplate for proper
voltage and frequency. See Section 3.0 for proper sizing of electrical supply and protection equipment in the
facility.
2.0 SAFETY INFORMATION
2.1 USAGE AND SAFETY INFORMATION
The HPU provides pressurized hydraulic fluid for performing aircraft maintenance.
To ensure safe operations, please read the following statements and understand their meaning. Also refer to your
aircraft manufacturer’s manual for other important safety information.
WARNING! —Warning is used to indicate the presence of a hazard that can cause severe personal injury,
death, or substantial property damage if the warning notice is ignored.
CAUTION! —Caution is used to indicate the presence of a hazard that will or can cause minor personal injury
or property damage if the caution notice is ignored.
2.2 EXPLANATION OF WARNING & DANGER SIGNS
Accidental Starts! Before servicing the HPU or equipment, always disconnect electrical power supply to prevent
accidental starting.
Rotating Parts! Keep hands, feet, hair, and clothing away from all moving parts to prevent injury. Never operate
the HPU with covers, shrouds, or guards removed.
Electrical Shock! Never touch electrical wires or components while the HPU is attached to the power source.
They can be sources of electrical shock. DO NOT operate HPU with cabinet panels removed.
Pressurized Fluid! Before servicing the HPU or equipment, always open the bypass valve to relieve any residual
pressure in the hydraulic system.

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Hydraulic Power Unit
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2.3 COMPONENT SAFETY FEATURES
•Pump/Motor coupling guard •Control circuit fuses
•Sheet metal panels •Motor overload protection
•Pressure and return system relief valves
2.4 FUNCTIONAL SAFETY FEATURES
•Emergency shut off switch •Calibration port shut off valve
•Floor lock •Fluid sample shut off valve
2.5 PERSONAL PROTECTION EQUIPMENT
•Safety glasses must be worn when operating the HPU.
•Additional equipment recommended by the fluid manufacturer (gloves, etc.).
2.6 SAFETY GUIDELINES
•Operator must be properly trained prior to operating the HPU.
•HPU power switch must be in "Off" position when connecting or disconnecting hoses to the aircraft.
•Bypass valve must be in the "Open" position when starting or stopping the HPU.
•Electrical power must be disconnected from the HPU and the bypass valve must be in the "Open" position
before servicing the HPU. (Reference Technical Manual for details on servicing the HPU.)
2.7 GENERAL COMMENT
The HPU is intended to be operated by personnel trained in the proper use in conjunction with the aircraft
maintenance manual.
The HPU must be used in accordance with the Technical and Operator Manuals and the intended aircraft.
3.0 PREPARATION PRIOR TO FIRST USE
3.1 GENERAL
Prior to operating the HPU, the user should become familiar with this Operator Manual.
3.2 SERVICING RESERVOIR
Fill the reservoir with the correct fluid (see label next to reservoir fill for correct type of fluid) until fluid level is above
the minimum fluid level mark but below the maximum fluid level. See Figure 6.3.1 Front Panel Controls for
reservoir fill location.
3.3 CONNECTING ELECTRICAL LEADS
Electrical Shock! Never touch electrical wires or components while electrical power is attached. Only qualified
electricians should connect the electrical leads.
Install plug onto the electrical cord. If motor rotation is not correct, change any two of the three leads at the plug.
Reference Section 3.0 Electrical Power and Protection Requirements for power requirements and fuse sizes.
(See 6.4 Start up Procedures before starting HPU.)
WARNING!
Balanced three phase voltage must be available to prevent overheating and damage to the motor.
Voltage unbalanced between phases occurs when the voltages differ from one another.
Some reasons for imbalance are:
1. Unequal loading of each phase
2. Poor connections in the supply
3. Single phase condition caused by blown fuses or bad connections
If these conditions occur in the incoming power system, a protective devise, such as a voltage monitor,
should be installed on the machine to prevent motor damage.

Model: 5J41
Hydraulic Power Unit
02/2023 | Rev. 03 Page | 3
4.0 TRAINING
4.1 TRAINING REQUIREMENTS
The employer of the operator is responsible for providing a training program sufficient for the safe operation of the
HPU.
4.2 TRAINING PROGRAM
The employer provided operator training program should cover safety procedures concerning use of the HPU in
and around the intended aircraft at the intended aircraft servicing location.
4.3 OPERATOR TRAINING
The operator training should provide the required training for safe operation of the HPU.
NOTE: Maintenance and Trouble Shooting are to be performed by a skilled and trained technician.
5.0 OPERATION
5.1 OPERATING PARAMETERS
•The user shall use the HPU in accordance with the aircraft manufacturer's instructions.
•The user shall operate the HPU in accordance with the Technical and Operator Manuals.
•The employer of the operator shall provide all necessary training.
•The electrical power supply for the HPU must include a fused disconnect using Type J or Type R fuses or
equivalent magnetic type circuit breakers designed for protecting an electrical motor. This necessary
equipment is for protection of the HPU, power cord, and customer-supplied plug and receptacle. Reference the
Table below:
ELECTRICAL POWER AND PROTECTION REQUIREMENTS
60 Hz Applications
Voltage
208
230
380
460
575
Full Load Amps
86.3
78
42.5
39
31.2
Locked Rotor Amps
481
435
330
218
174
Recommended Fuse Size
110
100
50
50
40
Maximum Fuse Size
125
110
60
60
45
50 Hz Applications
Voltage
200
220
380
415
440
Full Load Amps
89
78
45
43
39
Locked Rotor Amps
430
455
263
225
208
Recommended Fuse Size
110
100
60
50
50
Maximum Fuse Size
125
110
70
60
60
5.2 NUMERICAL VALUES
5.2.1 Fluid
(See Nameplate on unit for Model Number)
Model Number Fluid Type
5J11 ..................................... MIL-PRF-5606
5J21 ..................................... MIL-PRF-83282
5J31 ..................................... Aviation Phosphate Ester, Type IV and V
5J41 ..................................... MIL-PRF-87257

Model: 5J41
Hydraulic Power Unit
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5.2.2 Physical
Weight (Dry).........................1,650 lbs (748.43 kg)
Width.................................... 51 in (129.5 cm)
Height................................... 48.75 in (124 cm)
Depth.................................... 55 in (140 cm)
Power Cord..........................50 ft (15.24 m) long
Pressure Hoses....................25 ft (7.62 m).....................Standard Length
50 ft (15.24 m)...................Optional Length
-12 (¾ in, 19.1 mm)...........Working Diameter
Return Hoses.......................25 ft (7.62 m).....................Standard Length
50 ft (15.24 m)...................Optional Length
-16 (1 in, 25.4 mm)............Working Diameter
Hand Pump Hose.................15 ft (4.57 m).....................Standard Length
-4 (¼ in, 6.4 mm)...............Working Diameter
5.2.3 Hydraulic Pump
A pressure compensated, adjustable maximum volume piston pump
Maximum flow at 60 Hz...................................................20 gpm (75.7 lpm)
Maximum flow at 50 Hz...................................................16.6 gpm (62.8 lpm)
Maximum operating pressure at 50 Hz and 60 Hz ..........4000 psi (275.8 bar)
System pressure relief valve setting................................4250 psi (293 bar)
Performance Curve for 50 Hz and 60 Hz
5.2.4 Electric Motor
A 30 horsepower, TEFC electric motor is the prime mover for the HPU. This is attached to the hydraulic pump
using a pump/motor adapter and a spider/coupling rotating interface.
MOTOR POWER REQUIREMENTS
60 Hz Applications
50 Hz Applications
Voltage
Full Load Amps
Voltage
Full Load Amps
208
86.3
200
89
230
78
220
78
380
42.5
380
45
460
39
415
43
575
31.2
440
39
0
46
92
138
184
230
276
0.0 11.0 22.0 33.0 44.0 55.0 66.0 77.0 88.0
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
PRESSURE (BAR)
FLOW (LPM)
PRESSURE (PSI)
FLOW (GPM)
OPERATING RANGE
50Hz
60Hz

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Hydraulic Power Unit
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5.2.5 Filters
Pressure............................... 2 micron rating, non-bypass high collapse microglass type. Non-cleanable element.
Return ..................................5 micron rating, 15 psi (1.03 bar) bypass microglass type. Non-cleanable element.
Hand Pump (Option M) ........ 2 micron rating, non-bypass microglass type. Non-cleanable element.
Air/Desiccant........................ 3 micron filter, silica gel desiccant type. Non-cleanable element.
5.2.6 Hand Pump (Option M)
Two stage hand pump, low pressure stage 0−500 psi (0−34.47 bar) and 500−5,000 psi (34.47−344.74 bars) high
pressure stage. Pump automatically changes stage internally based on system pressure.
Low Pressure Stage.............Piston Diameter ................1½ in (38.1 mm)
Working Pressure .............0 −500 psi (0 −34.47 bar)
Displacement/Stroke.........2.1 in3 (34.4 cm3)
Force/100 psi (6.89 bar)....12.0 lbs/100 psi (7.74 N/bar)
High Pressure Stage............Piston Diameter ................5/8 in (15.88 mm)
Working Pressure .............500 −5,000 psi (34.47 −344.74)
Displacement/Stroke.........0.4 in3 (6.55 cm3)
Force/100 psi (6.89 bar)....2.2 lbs/100 psi (1.42 N/bar)
Pressure Relief Setting.........5,250 psi (362.0 bar)

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Hydraulic Power Unit
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5.3 LOCATION & LAYOUT OF CONTROLS
5.3.1 Front Panel Controls
Electrical Control Panel
See Section 5.3.2
Hydraulic Control Panel
See Section 5.3.3
Bypass Valve
For loading and unloading the motor driven hydraulic pump
Flowmeter
Displays the flow from the motor driven hydraulic pump
Pump Control Access
See Figure 5.3.5 - Hydraulic Pump Controls
Reservoir Selector
For selecting between using the aircraft reservoir or the HPU reservoir
Sight Gauge
Visual indicator displays the fluid level in the reservoir
Reservoir Fill Access
Locking cap for servicing the HPU reservoir
Desiccant Filter
Access to the reservoir air filter/desiccant filter
Hand Pump (Option M)
Access for hand pump and relief screw, handle stored inside
Floor Lock
Locking/unlocking, foot actuated and released floor lock

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Hydraulic Power Unit
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5.3.2 Electrical Control Panel
Emergency Stop
Removes power to all electrical devices, must turn to reset
Stop Switch
Turns off the electric motors driving the hydraulic pump and cooling fan
Start Switch
Turns on the electric motors driving the hydraulic pump and cooling fan
HPU Power "On" Indicator Light
Light is illuminated when the electric motors driving the hydraulic pump and cooling
fan are on
High Fluid Temperature Indicator
Light (Option S)
Light is illuminated when the return fluid temperature reaches 170F (77C) or
above. The HPU will shut down when light is illuminated. The HPU can be re-started
when the fluid has cooled and the indicator light is off
High Reservoir Fluid Level
Indicator Light (Option L)
Light is illuminated when the fluid level in the reservoir is above the normal operating
range. The HPU will shut down until the fluid level is restored to a normal operating
level
Low Reservoir Fluid Level
Indicator Light (Option L)
Light is illuminated when the fluid level in the reservoir is below the normal operating
range. The HPU will shut down until the fluid level is restored to a normal operating
level
Voltage/Phase Monitor Indicator
Light (Options G − J)
Light is illuminated if any of the following conditions occur
- Voltage imbalance between L1, L2, L3, greater than 5%
- Loss of voltage from L1, L2, L3
- Over voltage from L1, L2, L3, greater than 5%
- Change in phase orientation between L1, L2, L3. The HPU will shut down until
the electrical problem is corrected
Clogged Pressure Filter Indicator
Light (Option R)
Light is illuminated when the pressure filter element requires changing. The HPU will
not shut down when illuminated. Pressing the illuminated button will reset the light

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Hydraulic Power Unit
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5.3.3 Hydraulic Control Panel
System Pressure Gauge
Displays the system pressure on an analog fluid dampened gauge
Pyrometer (Option K)
Displays the fluid temperature in the return system on an analog gauge. A
warning indicator preset to 160°F (71°C) warns of high operating temperature
Pressure Gauge Calibration Port
(Option Q)
Allows for calibration of the system pressure gauge up to the operating pressure of
HPU. Calibration port shut off valve must be used in conjunction with the calibration
port
Calibration Port Shut Off Valve
(Part of Calibration Port Option Q)
Used to shut off pressure to the calibration port. This valve should only be opened
when the external standard gage is attached. (See Operation & Service Manual for
proper procedure)

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Hydraulic Power Unit
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5.3.4 Rear Panel Controls
* Fluid Pressure System
The source of pressurized fluid from the HPU that flows to the aircraft pressure
system through the pressure hose
* Fluid Return System
Fluid returning to the HPU from the aircraft that flows through the return hoses
Pressure Fluid Filter
Filters the pressurized fluid before it flows to the aircraft pressure system
Pressurized Fluid Sample Port
A sample valve is provided to obtain a fluid sample for analysis. In order to obtain a
representative sample
Hand Pump Pressure Filter
(Option M)
Filters the pressurized fluid before it flows to the aircraft system
Hose Racks
Location for storing the pressure, return and optional hand pump hoses when not in
use
Hose Racks
Location for storing the pressure, return and optional hand pump hoses when not in
use
Power Cord Hanger
Location for storing the power cord when not in use
Split System (Optional) consists of two (2) each of these items.

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Hydraulic Power Unit
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5.3.5 Hydraulic Pump Controls
The hydraulic pump flow control and pressure control are located on the front panel.
Flow Control
This control is used to set the maximum flow required from the HPU
Pressure Control
The pressure control is used to set the system pressure of the HPU during operation

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5.3.6 Hand Pump Controls (Option M)
Reference 6.9 Hand Pump Operation
Pump Handle
Located inside the front access door is the hand pump handle used for opening and
closing the hand pump relief screw and stroking the hand pump arm
Hand Pump Relief Screw
Accessed through the front panel opening, this screw allows opening and closing of
the hand pump hydraulic circuit using the hand pump handle
Hand Pump Arm
The handle is used to access the hand pump arm used for up and down motion to
produce hydraulic flow and pressure
Hand Pump Pressure Gauge
Displays the hand pump pressure on analog fluid dampened gauge

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5.3.7 Split System Controls (Option C)
Reference 6.7 Split System Operation
Pressure Manifold
Houses the pressure valves
Fluid Pressure Ball Valve
Used to turn on and off the flow to separate aircraft systems. Always use in either
fully open or fully closed position; never use in a partially open position
Fluid Pressure Hose
Connects HPU to aircraft pressure systems
Fluid Return Hose
Connects HPU to aircraft return systems
Fluid Return Ball Valve
Used to turn on and off the flow from separate aircraft systems. Always use in either
fully open or fully closed position; never use in a partially open position
WARNING!
NEVER open or close split system valves without shutting off the Hydraulic Power Unit. Damage to the
aircraft system or reservoir may result if either return line valve is closed while the machine is running.

Model: 5J41
Hydraulic Power Unit
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5.3.8 Split System Crossover Check Controls (Option D)
Reference 6.8 Split System Crossover Check Operation
Pressure Gauge
Displays the pressure in each aircraft system
Hose Assembly
Connects HPU to aircraft pressure system
Ball Valve
Turns on and off the fluid for taking contamination samples
Crossover Check Manifold
Houses the valves and gauges
Cartridge Needle Valve
Used to turn on and off the flow to the separate aircraft pressure systems. Always
use in either fully open or fully closed position; never use in a partially open position
Check Valve
Prevents cross flow from System 2 pressure line to System 1 pressure line
WARNING!
NEVER open or close split system valves without shutting off the Hydraulic Power Unit. Damage to the
aircraft system or reservoir may result if either return line valve is closed while the machine is running.

Model: 5J41
Hydraulic Power Unit
02/2023 | Rev. 03 Page | 14
5.4 START UP PROCEDURES
5.4.1 Procedure for First Time or Different Electrical Supply ONLY
Phase Monitor (Options G − J Only): Check that the phase monitor light on the instrument panel is not
illuminated. If the light is illuminated, change any two of the three input leads at the plug. Once the phase monitor
light is not illuminated with power attached, check for proper motor rotation.
a. Remove the pump/motor coupling guard.
Reference Pump/Motor Coupling Access.
Rotating Parts! Keep hands, feet, hair, and clothing
away from all moving parts to prevent injury. Never operate
the HPU with covers, shrouds, or guards removed.
b. Verify that the unit has been prepared for use by
connecting electrical leads and servicing the reservoir.
(Reference Section 4.0 Preparation Prior to First Use.)
c. Keeping hands clear of the pump/motor coupling area,
momentarily press the start button and immediately press
the stop button.
d. Observe direction of rotation of the pump/motor coupling.
When the Operator is facing the front panel, the
pump/motor coupling should be rotating in a clockwise
direction.
Electrical Shock! Never touch electrical wires or components while the HPU is attached to the power source.
They can be sources of electrical shock.
Do not operate HPU with cabinet panels removed.
e. If the pump/motor coupling is rotating in a counter-clockwise direction, change any two of the three leads at the
plug. Observe direction of rotation to verify that pump/motor is rotating in a clockwise direction.
f. Replace the pump/motor coupling guard.
5.4.2 Initial Start Up of the HPU
a. Unit must be prepared per Section 4.0 Preparation Prior to First Use and Section 5.4.1 First Time or Different
Electrical Supply ONLY before starting the HPU.
b. Operator must be familiar with this manual and be properly trained prior to starting the HPU.
c. Connect quick disconnects to hose ends or cap the pressure and return hose ends.
d. Place the reservoir selector valve in "HPU Reservoir" position.
e. Place the bypass valve in the "Open" position.
f. Press the start switch and adjust the flow control until 6 gpm (22.71 lpm) is displayed on the flowmeter. (If no
flow displays on the flowmeter after adjusting the flow control, reference Trouble Shooting 9.2 No Flow).
g. Close the bypass valve, adjust the pressure control until 3,000 psi (206.84 bar) is displayed on the pressure
gauge. (If no pressure displays on the system pressure gauge after adjusting the pressure control, reference
Trouble Shooting 9.4 No Pressure or Reduced Pressure).
h. Open the bypass valve; press the stop switch.
NOTE: Maintenance and Trouble Shooting are to be performed by a skilled and trained technician.
5.5 PRELIMINARY ADJUSTMENTS FOR OPERATION
The following are basic to the operation of the HPU and should be thoroughly understood. The pressure and flow
controls have lock nuts to prevent rotation of the control shaft during operation. These nuts should be moved away
from the pump during adjustment of flow or pressure in order to eliminate binding of the control shafts.
5.5.1 Flow Control Adjustment
a. Open bypass valve.
b. Select "Hydraulic Power Unit" position with reservoir selector valve.
c. Start HPU.
d. Adjust flow control on pump for maximum desired flow. Observing the flowmeter, read flow in gallons (liters)
per minute directly from flowmeter. Be sure the control shaft lock nut is loose during adjustment. Tighten after
adjustment to maintain setting.
Pump/Motor Coupling Access

Model: 5J41
Hydraulic Power Unit
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5.5.2 Pressure Control Adjustment
a. Open bypass valve.
b. Select "Hydraulic Power Unit" position with reservoir selector valve.
c. Start HPU.
d. Close bypass valve.
e. Adjust pressure control for desired pressure; observing the system pressure gauge, read in psi (bar). Be sure
the control shaft lock nut is loose during adjustment. Tighten after adjustment to maintain setting.
NOTE: Once the flow and pressure controls have been adjusted, it is not necessary to change these
settings after each operation unless desired.
5.5.3 Reservoir Selector Valve Operation
Operation of the reservoir selector valve allows the operator to select either the aircraft reservoir (closed loop) or
the HPU reservoir (open loop).
CAUTION!
The reservoir selector valve should only be operated when the HPU is not running. The operation of the
reservoir selector valve should be done prior to starting the HPU.
a. Aircraft Reservoir Position (Closed Loop)
In this position, the HPU is dependent on the aircraft reservoir and system for an adequate supply of fluid.
Cavitation, due to an inadequate fluid supply from the aircraft, may be indicated by erratic fluctuation of the
system pressure gauge or flowmeter. At times, the aircraft fluid supply will be restricted due to small return oil
lines in the aircraft. If this is a problem, decrease the flow control setting until the cavitation is eliminated.
b. HPU Reservoir Position (Open Loop)
In this position, the HPU reservoir supplies fluid to the pump and accepts return fluid from the aircraft. It is
desirable to operate the HPU in this mode since it eliminates any possibility of cavitation.
Since the HPU reservoir is vented to atmosphere and the aircraft is at a higher level, it is normal for the aircraft
reservoir to drain into the HPU reservoir. It is, therefore, necessary to be sure that sufficient room is available
in the HPU reservoir to accommodate the additional fluid.
CAUTION!
The aircraft system reservoir must be serviced after completion of operational testing.
In the "HPU Reservoir" position, faster landing gear swings are usually possible since there is no restriction to
flow at the pump inlet.
5.5.4 Bypass Valve Operation
The bypass valve is used for unloading the pump. The valve should be either in the fully open or fully closed
position only. Do not operate the valve in a partially open position.
a. Start Up Operation
The bypass valve must be opened prior to starting the HPU in order to allow the motor to start under a no load
condition and not pressurize the aircraft hydraulic system.
b. Shut Down Operation
Prior to shutdown, the bypass valve must be opened to bleed off any residual system pressure.
CAUTION!
Excessive heat, which could damage machine components, will be generated if the bypass valve is
partially open or is used for regulating flow or pressure.
•Use the flow and pressure controls for regulation.
•Use the bypass valve for unloading the system only.
5.6 BLEEDING AIR FROM SYSTEM
Rapid fluctuations of the pressure gage and flow-meter are indications of cavitation or entrapped air in the
hydraulic lines and/or components. Air may enter the system when:
•Operating the unit with insufficient oil in the reservoir.
•Changing a component on the aircraft.
•Changing hose connections and/or couplings.