North Star M51481A Owner's Manual

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M51481A

ITEM NUMBER: 51481
SERIAL NUMBER: _____________

Owner’s Manual

12V DC Portable Air Compressor

Instructions for Installation/Set-up, Operation, Maintenance & Storage

This NorthStar® compressor has a single-stage, single-cylinder pump made with a heavy-duty cast iron cylinder for
long life, and a compact design rated for 135 maximum PSI. Its continuous-duty rating ensures long-lasting
performance, and its cast iron pump head ensures superior heat dissipation.

Read and understand this Owner’s Manual completely before using. Keep this manual for future review. Failure to
properly set up, operate and maintain the compressor in accordance with this manual could result in serious injury or
death to operator or bystanders.

WARNING: SPECIAL HAZARDS

 Injection Injury: High-pressure air stream can pierce skin and underlying tissues, leading to serious injury and possible

amputation. Such an injection injury can result in blood poisoning and/or severe tissue damage.

 Flying Debris: High-pressure air stream can cause flying debris and possible surface damage.
 Not For Breathing Air: NorthStar compressors are NOT designed, intended, or approved for supplying breathing air. No

compressed air should be used for breathing unless air is treated in accordance with applicable standards.

 Fire/Explosion: Sparks from air powered tool heads or attachments can ignite fuel or other flammable liquids or vapors in

the vicinity. Exceeding the maximum pressure for air tools or attachments could cause them to explode.

 Burns: Compressor pump, motor and discharge tubing are hot surfaces that can cause burn injuries.
 Electric Shock: Operating equipment in wet conditions or where not properly grounded can cause electric shock.

Detailed safety information about these hazards appears throughout this manual.

Equipment Protection Quick Facts

Inspect Upon Delivery: FIRST! Inspect for missing or damaged components. See the “Initial Set-Up” section for

instructions on reporting missing or damaged parts.

Pump: The Pump is an oil-free design. No oil is required.

Regulator: This air compressor includes a regulator to maintain constant pressure in the outlet hose line and provide

reduced pressure to the appropriate air tool being used.
Run Pump Unloaded for Break-in Period: Before initial use, run the compressor for 30 minutes to break in the

pump parts.
Follow Maintenance Schedule: Pump, air filter, and tank require periodic inspection and servicing to provide

efficient function and long life. See “Maintenance Schedule” for frequency of servicing.

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Table of Contents

Equipment Protection Quick Facts ........................................................................................................................................ 1

Table of Contents ........................................................................................................................................................ 2

About Your Air Compressor ....................................................................................................................................... 3

Specifications .............................................................................................................................................................. 4

Component Identification ........................................................................................................................................... 5

Safety Signal Words .................................................................................................................................................... 6

Hazard Signal Word Definitions ............................................................................................................................................ 6

Safety Labeling ............................................................................................................................................................ 7

Safety Decal Locations ......................................................................................................................................................... 7

Safety Decals ........................................................................................................................................................................ 8

Initial Set-Up ................................................................................................................................................................ 9

Step 1. Inspect & Unpack ........................................................................................................................................................ 9

Step 2. Assembly ..................................................................................................................................................................... 9

Step 3. Select Suitable Location ............................................................................................................................................. 9

Operation ................................................................................................................................................................... 10

Follow Operation Safety Rules ............................................................................................................................................. 10

Prepare for Operation ............................................................................................................................................................ 10

Proper Air Hose and Tool Use .............................................................................................................................................. 11

Pressure Control Related Devices ...................................................................................................................................... 11

Compressor - Tool Requirements ....................................................................................................................................... 11

Attaching/Disconnecting Air Hose and Tools ...................................................................................................................... 11

Using Compressor for Spraying ........................................................................................................................................... 11

Flammable Materials ........................................................................................................................................................... 11

Moisture in Compressed Air ................................................................................................................................................ 11

Shutdown ............................................................................................................................................................................... 12

Procedure ........................................................................................................................................................................... 12

For Malfunction During Operation ....................................................................................................................................... 12

Maintenance & Repair ............................................................................................................................................... 13

Maintenance Schedule Summary ............................................................................................................................. 13

Detailed Instructions – Maintenance & Repair ........................................................................................................ 13

Inspect Safety/Relief Valve ................................................................................................................................................. 13

Inspect Air Filter .................................................................................................................................................................. 13

Keep Compressor Clean ..................................................................................................................................................... 13

Inspect Compressor for Air Leaks ....................................................................................................................................... 13

Drain Receiver Tank and Inspect Tank ............................................................................................................................... 13

Troubleshooting ........................................................................................................................................................ 14

Parts List – Model 51481 Rev A ................................................................................................................................ 15

Parts List – Model 51481 Rev A ................................................................................................................................ 16

Limited Warranty ....................................................................................................................................................... 17

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About Your Air Compressor

Thank you for purchasing a NorthStar air compressor! It
is designed for long life, dependability, and top
performance.

Intended Use. Provides compressed air used primarily
for operating air tools and pressurizing other objects
that require high air pressure, such as tires. Do not
use for low-pressure objects such as balloons, air
mattresses, and sport balls, which can explode
quickly and easily. Special precautions are
necessary when used for cleaning to prevent flying
debris hazards.

Supplies Required. Normal operation will require you
to supply:

 Pressure regulator
 Personal protection equipment

See “Specifications” section for more detail.

Site Location. See “Select Suitable Location” on page 9
for more information.

Personal Protection. Wear safety apparel during
operation, including safety glasses with side and top
protection.

Adult Control Only. Only trained adults should set up
and operate the air compressor. Do not let children
operate.

Under The Influence. Never operate, or let anyone else
operate, the air compressor while fatigued or under
the influence of alcohol, drugs, or medication.

Keep this manual for reference and review.

ATTENTION: Rental Companies and Private
Owners who loan this equipment to others!

All persons to whom you rent/loan this air compressor
must have access to and read this Owner’s Manual.
Keep this manual with the air compressor at all times
and advise all persons who will operate the machine to
read it. You must also provide personal instruction on
how to safely set-up and operate the air compressor
and remain available to answer any questions a
renter/borrower might have. Owner’s Manuals are
available from NorthStar at 1-800-270-0810.

For any questions, comments, problems or part orders,
call NorthStar at 1-800-270-0810.

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Specifications

Item #

51481

Tank Size

1 Gallon

Motor Voltage

12 Volts DC

Maximum Current Consumption

36 Amps

Recommended Fuse

50 Amps

Battery Size (minimum)

50 Ah

Horsepower

3/4 HP

Maximum Working Pressure

135 PSI

Volume Rating

0.85 CFM @ 135 PSI

1.30 CFM @ 90 PSI

2.00 CFM @ 40 PSI

Continuous Use (72°F & 100 PSI)

60 Minutes

Maximum Ambient Temperature

122°F

Minimum Ambient Temperature

14°F

Noise/Decibel Level

77 dBA

Dimensions (in)

14.2 (L) x 13 (W) x 12.2 (H)

Weight (lbs)

31.5

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Component Identification

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10 9 8

11 7 4 5 2 3 6 3 12

1. Pressure Switch - Auto/Off Switch: In the AUTO position, the compressor shuts off automatically when the tank pressure reaches the maximum

preset pressure. In the OFF position, the compressor will not operate. The switch should be in the OFF position when connecting or disconnecting the

power cord from a 12-Volt power suppply. NEVER attempt to adjust this pressure switch.

2. ASME Safety Valve: The valve is designed to prevent a system failure by relieving pressure from the system when the compressed air reaches a

predetermined level. The valve is preset by the manufacturer and must not be modified. To verify the valve is working properly, pull on the ring. Air

pressure should escape. When the ring is released, it will reseat.

3. Air Tank Pressure Gauge: This pressure gauge indicates the reserve air pressure in the air tank.

4. Pressure Switch Unloader: Vents discharge air to the atmosphere during the start/stop operation.

5. Regulator: The air coming from the air tank is controlled by the regulator knob. Turn the regulation knob clockwise to increase the discharge pressure,

and counter-clockwise to decrease the discharge pressure. See the Operating Instructions section for recommended pressure range.

6. Compressor Air Filter: The air filter is designed to clean air coming into the pump. To ensure the pump continuously receives a clean, cool and dry air

supply, this filter must always be clean and the ventilation opening free from obstructions.

7. Tank Drain Valve: The tank drain valve is used to remove moisture from the air after the compressor is shut off and the air is emptied from the tank.

Drain the moisture daily after each use.

8. Cable with Alligator Clip: The cable has been connected to a 10AWG fuse holder with 50A fuse. Connect the RED clamp to the positive (+) pole

and the BLACK clamp to the negative (-) pole of a 12V battery.

9. Check Valve: The check valve is used to seal off and maintain pressure levels after the top end pressure setting of the pressure switch is reached.

The check valve works in conjunction with the pressure switch unloader to provide a load-less start to the compressor system. A quick burst of air

escaping from the pressure switch unloader after an electric unit reaches the top end indicates that the check valve is working properly. If the

compressor has a mysterious leak after stopping that cannot be traced elsewhere, the check valve may require servicing or replacing.

10. Fuse: A 10 AWG fuse holder is installed with the 50 amp fuse. Replacement fuse available through Northern Tool & Equipment as part # 794969 or

the customer can purchase a replacement Maxi™ ATX fuse through their local supplier.

11. Discharge Tube: The discharge tube carries compressed air from the pump to the check valve, and then to the storage tank. It becomes very hot

during use and can cause severe burns. Do not touch.

12. Air Receiver Tank: 1 Gallon tank that holds pressurized air.

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Safety Signal Words

DANGER

WARNING

CAUTION

CAUTION

NOTICE

Hazard Signal Word Definitions

This is the safety alert symbol. It is used to alert you to
potential personal injury hazards. Obey all safety
messages that follow this symbol to avoid possible injury
or death.

DANGER (red) indicates a hazardous situation, which if
not avoided, will result in death or serious injury.

WARNING (orange) indicates a hazardous situation,
which if not avoided, could result in death or serious
injury.

CAUTION (yellow), used with the safety alert symbol,
indicates a hazardous situation, which if not avoided,
could result in minor or moderate injury.

CAUTION (yellow), without the safety alert symbol, is
used to address practices not related to personal injury.

NOTICE is used to address practices not related to
personal injury.