Save This ManualKeep this manual for the safety warnings and precautions, assembly,
operating, inspection, maintenance and cleaning procedures� Write the product’s serial number in the
back of the manual near the assembly diagram (or month and year of purchase if product has no number)�
Keep this manual and the receipt in a safe and dry place for future reference� 18j
When unpacking, make sure that the product is intact
and undamaged� If any parts are missing or broken,
The warnings, precautions, and instructions discussed in this instruction manual cannot cover all possible
conditions and situations that may occur� It must be understood by the operator that common sense
and caution are factors which cannot be built into this product, but must be supplied by the operator�
9+->*7+-*,=4<,88'=8*)3/*9+:4-/((+-6**
Y//4*9+->*1.1V*7-+:*3/1)B*+'<B*(31-4*/>8/(*
+-*:+W'=8*41-)(6**Damaged or entangled
cords increase the risk of electric shock�
3� K/-(+=1<*(17/)V
a� F)1V*1</-)B*.1)93*.31)*V+,*1-/*>+'=8*1=>*
,(/*9+::+=*(/=(/*.3/=*+4/-1)'=8*)3'(*
9+:4-/((+-6**U+*=+)*,(/*)3'(*9+:4-/((+-*
.3'</*V+,*1-/*)'-/>*+-*,=>/-*)3/*'=7<,/=9/*
+7*>-,8(B*1<9+3+<*+-*:/>'91)'+=6 A moment
of inattention while operating a compressor
may result in serious personal injury�
RECOMMENDED� If you choose to use an
extension cord, use the following guidelines:
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0 – 618161614
6�1 – 101816U+*=+)*,(/6
10�1 – 121616U+*=+)*,(/6
12�1 – 161412U+*=+)*,(/6
a� Make sure your extension cord
is in good condition�
25′50′100′150′
Q;NSH^
b� Be sure to use an extension cord which
is heavy enough to carry the current your
product will draw� An undersized cord will
cause a drop in line voltage resulting in loss
of power and overheating� Table A shows the
correct size to use depending on cord length
and nameplate ampere rating� If in doubt,
use the next heavier gauge� The smaller
the gauge number, the heavier the cord�
16� Industrial applications must follow OSHA guidelines�
17� Maintain labels and nameplates on the
compressor� These carry important safety
information� If unreadable or missing, contact
Harbor Freight Tools for a replacement�
18� This product is not a toy�
Keep it out of reach of children�
19� Operate unit on level surface� Check oil level
daily and fill to marked level if needed�
20� People with pacemakers should consult their
physician(s) before use� Electromagnetic fields in
close proximity to heart pacemaker could cause
pacemaker interference or pacemaker failure�
grounding provides a path of least resistance for
electric current to reduce the risk of electric shock�
This compressor is equipped with an electric
cord having an equipment-grounding conductor
and a grounding plug� The plug must be
plugged into a matching outlet that is properly
installed and grounded in accordance
with all local codes and ordinances�
2� Do not modify the plug provided –
if it will not fit the outlet, have the proper
outlet installed by a qualified electrician�
3� Improper connection of the equipment-grounding
conductor can result in a risk of electric shock�
The conductor with insulation having an outer
surface that is green with or without yellow
stripes is the equipment-grounding conductor�
If repair or replacement of the electric cord or
plug is necessary, do not connect the equipmentgrounding conductor to a live terminal�
4� Check with a qualified electrician or service
personnel if the grounding instructions are
not completely understood, or if in doubt as to
whether the compressor is properly grounded�
5� Use only 3-wire extension cords that have
3-prong grounding plugs and 3-pole receptacles
that accept the compressor’s plug�
circuit that has an outlet that looks like the one
illustrated above in C_$*&GP*dDK-+=8*K<,8*1=>*J,)</)� The compressor has a grounding
plug that looks like the plug illustrated above
in C_$*&GP*dDK-+=8*K<,8*1=>*J,)</)�
8� The outlet must be properly installed and grounded
in accordance with all codes and ordinances�
9� Do not use an adapter to connect this
compressor to a different outlet�
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KFM
P@O
FP@O
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NKF
Pounds per square inch of pressure
Cubic Feet per Minute flow
Cubic Feet per Minute flow
at standard conditions
National pipe thread, tapered
National pipe thread, straight
F4/9'7'91)'+=(
Double Insulated
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Electrical Rating
Air Outlet Size1/4″ -18 NPT
Air Pressure
Air Tank Capacity20 Gallons
Air Flow Capacity4�0 SCFM @ 90 PSI
Sound Level85 dBA
Oil Capacity5�6 oz�
Oil TypeSAE 30W, non-detergent, Air Compressor Oil
2� The oil level should be at the center of the “full” level
on the Oil Sight Glass�
Add oil as needed to maintain this level�
Do not let the oil level go below
the center dot and do not overfill the oil
so that it is above the center dot�
J'<*
T-/1)3/-
3� To add oil:
a� Remove the Oil Breather�
b� Using a funnel to avoid spills, pour enough
oil into the Pump Crankcase to reach
the “full” level in the Oil Sight Glass�
c� Replace the Oil Breather�
N+)/2 SAE 30W, non-detergent,
Air Compressor Oil (sold separately) is
recommended for use with this compressor�
4� If uncertain which oil to use for this compressor,
call Harbor Freight Tools customer service
at 1-888-866-5797 for assistance�
with this compressor, incorporate additional
components, such as an in-line oiler, a filter,
or a dryer (all sold separately), as shown on
Figure A on page 10 and Figure B on page 11�
Consult air tool’s manual for needed accessories�
1� Designate a work area that is clean and well-lit�
The work area must not allow access by
children or pets to prevent injury�
2� Locate the Compressor on a flat level surface to
ensure proper pump lubrication and to prevent
damage to the unit. Keep at least 12″ of space
around the unit to allow air circulation�
S/=/-1<*J4/-1)'+=
1� Close the Drain Valve�
2� Check for oil leaks and check the oil level
(See Checking the Oil on page 8)�
3� Close the in-line Shutoff Valve between
the compressor and the air hose�
4� Plug the Power Cord into a grounded
120 VAC electrical outlet�
5� Pull the ring on Safety Valve to release pressure�
6� Turn the Power Switch to AUTO�
7� Allow the Air Compressor to build
up pressure until it cycles off�
N+)/2 At the beginning of the day’s first use
of the Air Compressor, check for air leaks by
applying soapy water to connections while the
Air Compressor is pumping and after pressure cutout� Look for air bubbles� If air bubbles are present
at connections, tighten connections� Do not use the
Air Compressor unless all connections are air tight,
the extra air leaking out will cause the compressor to
operate too often, increasing wear on the compressor�
N+)/2 As long as the Power Switch is ON, the operation
of the Air Compressor is automatic, controlled by an
internal pressure switch� The Compressor will turn on
automatically when the air pressure drops to 105 PSI,
and will turn off automatically when the
air pressure reaches 135 PSI�
3� Route the power cord from the compressor
to the grounded wall outlet, along a safe path
without creating a tripping hazard or exposing
the power cord to possible damage�
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MNf[LI*GNU*U;GH^*@LJO*
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4-/((,-/*(.')936**Any change to the
automatic pressure levels may cause excess pressure to
accumulate, causing a hazardous situation�
8� Adjust the Regulator so that the air output is
enough to properly power the tool, but the output
will not exceed the tool’s maximum air pressure
at any time� Turn the knob clockwise to increase
the pressure and counter-clockwise to decrease
pressure� Adjust the pressure gradually, while
checking the air output gauge to set the pressure�
9� Make sure the air tool’s throttle or switch is in the
off position� Connect the air tool to the air hose�
10� Open the in-line Shutoff Valve�
11� Use the air tool as needed�
12� After the job is complete, turn the Power Switch OFF�
13� Unplug the Air Compressor�
14� Close the in-line Shutoff Valve�
15� Bleed air from the tool then disconnect the tool�
If it is necessary to quickly depressurize the Compressor, turn the Power Switch OFF�
Then, pull on the ring on the Safety Valve to quickly release stored air pressure�
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1� If the Compressor automatically shuts off
before reaching its normal cutoff pressure:
a� Shut off all tools�
b� Turn Power Switch OFF
c� Unplug Compressor�
d� Wait until the Compressor cools down
(about 10 minutes);
e� Plug in Compressor�
f� Turn Power Switch ON�
g� Resume operation�
2� Possible causes of repeated automatic
shut off of the compressor are:
a� Using an extension cord that
is too long or narrow;
b� An air leak or open hose causing the compressor
Following are general guidelines for maintenance checks of the Air Compressor�
N+)/2 The environment in which the compressor is used, and the frequency of use will affect how often
you will need to check the Air Compressor components and perform maintenance procedures�
U1'<V2
a� Check oil level�
b� Check for oil leaks�
c� Make sure all nuts and bolts are tight�
d� Drain moisture from air tank�
e� Check for abnormal noise or vibration�
f� Check for air leaks�
g� Wipe off any oil or dirt from the compressor�
*
**
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a� Inspect Air Filter�
b� Inspect Oil Breather�
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Inspect Safety Valve�
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Replace Pump oil�***
* To check for air leaks, apply soapy water to joints while
the Air Compressor is pressurized� Look for air bubbles�
** To clean the compressor surface, wipe with
a damp cloth, using a mild detergent or mild solvent�
*** Use SAE 30W, non-detergent,
Air Compressor Oil only (sold separately)�
Page 15
J'<*O1'=)/=1=9/
Check the oil periodically for clarity� Replace oil if it appears milky or if debris is present,
or every 6 months, or 100 operation hours, whichever comes first�
Replace the oil more frequently if compressor is used in harsh environments such as high heat or high humidity�
4� When the oil is completely drained from the Pump,
replace the Oil Drain Bolt�
5� Fill the Pump with new SAE 30W, non-detergent,
Air Compressor Oil to the FULL level
on the Oil Sight Glass (5�6 oz�)�
6� Replace and tighten the Oil Breather�
7� Discard the old oil according to local,
state and federal regulations�
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The Moisture Drain is located under the Tank� It must be used daily to release all trapped air and
moisture from the Tank� Doing this will eliminate condensation and prevent tank corrosion�
1� Turn the Power Switch off�
2� Place a collection pan under the Drain Valve�
3� Turn the Drain Valve to open it� Tilt
Compressor forward to drain�
4� When all the pressure and moisture are released,
close the Drain Valve�
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Check the Air Filter weekly to see if it needs replacement�
Replace the filter more often if compressor is used in dirty environments�
THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDED THE PARTS LIST AND ASSEMBLY DIAGRAM
IN THIS MANUAL AS A REFERENCE TOOL ONLY� NEITHER THE MANUFACTURER OR DISTRIBUTOR
MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND TO THE BUYER THAT HE OR SHE IS
QUALIFIED TO MAKE ANY REPAIRS TO THE PRODUCT, OR THAT HE OR SHE IS QUALIFIED TO REPLACE
ANY PARTS OF THE PRODUCT� IN FACT, THE MANUFACTURER AND/OR DISTRIBUTOR EXPRESSLY
STATES THAT ALL REPAIRS AND PARTS REPLACEMENTS SHOULD BE UNDERTAKEN BY CERTIFIED AND
LICENSED TECHNICIANS, AND NOT BY THE BUYE R� THE BUYER ASSUMES ALL RISK AND LIABILITY
ARISING OUT OF HIS OR HER REPAIRS TO THE ORIGINAL PRODUCT OR REPLACEMENT PARTS
THERETO, OR ARISING OUT OF HIS OR HER INSTALLATION OF REPLACEMENT PARTS THERETO�
L/9+->*K-+>,9)](*F/-'1<*N,:0/-*^/-/2*
N+)/2 If product has no serial number, record month and year of purchase instead�
N+)/2 Some parts are listed and shown for illustration purposes only,
and are not available individually as replacement parts�
Harbor Freight Tools Co� makes every effort to assure that its products meet high quality and durability standards,
and warrants to the original purchaser that this product is free from defects in materials and workmanship for the
period of 90 days from the date of purchase� This warranty does not apply to damage due directly or indirectly,
to misuse, abuse, negligence or accidents, repairs or alterations outside our facilities, criminal activity, improper
installation, normal wear and tear, or to lack of maintenance� We shall in no event be liable for death, injuries
to persons or property, or for incidental, contingent, special or consequential damages arising from the use of
our product� Some states do not allow the exclusion or limitation of incidental or consequential damages, so the
above limitation of exclusion may not apply to you� THIS WARRANTY IS EXPRESSLY IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS�
To take advantage of this warranty, the product or part must be returned to us with transportation charges
prepaid� Proof of purchase date and an explanation of the complaint must accompany the merchandise�
If our inspection verifies the defect, we will either repair or replace the product at our election or we may
elect to refund the purchase price if we cannot readily and quickly provide you with a replacement� We will
return repaired products at our expense, but if we determine there is no defect, or that the defect resulted
from causes not within the scope of our warranty, then you must bear the cost of returning the product�
This warranty gives you specific legal rights and you may also have other rights which vary from state to state�