Central Pneumatic 93271 User manual

®
21 GALLON, 230 VAC,
CAST IRON VERTICAL
AIR COMPRESSOR
OPERATING INSTRUCTIONS
®
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit ourWeb site at http://www.harborfreight.com
Copyright©2005 by Harbor Freight Tools®. All rights reserved. No portion of
this manual or any artwork contained herein may be reproduced in any shape
or form without the express written consent of Harbor Freight Tools.
For technical questions, please call 1-800-444-3353.
93271

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 2
SPECIFICATIONS
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SAVE THIS MANUAL
You will need this manual for the safety warnings and precautions, assembly,
operating, inspection, maintenance and cleaning procedures, parts list and
assembly diagram. Keep your invoice with this manual. Write the invoice
number on the inside of the front cover. Keep this manual and invoice in a safe
and dry place for future reference.
GENERAL SAFETY WARNINGS AND PRECAUTIONS
1. KEEP WORK AREA CLEAN AND DRY. Cluttered, damp, or wet work areas invite
injuries.
2. KEEP CHILDREN AWAY FROM WORK AREA. Do not allow children to handle
this product.
3. STORE IDLE EQUIPMENT. When not in use, tools and equipment should be stored
in a dry location to inhibit rust. Always lock up tools and equipment, and keep out of
reach of children.
4. DO NOT USE THIS PRODUCT IF UNDER THE INFLUENCE OF ALCOHOL OR
DRUGS. Read warning labels on prescriptions to determine if your judgement or
reflexes are impaired while taking drugs. If there is any doubt, do not attempt to
use this product.
5. USE EYE, HAND, AND HEARING PROTECTION. Wear ANSI approved safety
impact goggles, hearing protection, and heavy-duty work gloves when using this
product.
REV 10/05

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 3
6. DRESS SAFELY. Do not wear loose clothing or jewelry, as they can become caught
in moving parts. Wear a protective hair covering to prevent long hair from becoming
caught in moving parts. If wearing a long-sleeve shirt, roll sleeves up above el-
bows.
7. DO NOT OVERREACH. Keep proper footing and balance at all times to prevent
tripping, falling, back injury, etcetera.
8. INDUSTRIAL APPLICATIONS MUST FOLLOW OSHA REQUIREMENTS.
9. STAY ALERT. Watch what you are doing at all times. Use common sense. Do not
use this product when you are tired or distracted from the job at hand.
10. CHECK FOR DAMAGED PARTS. Before using this product, carefully check that it
will operate properly and perform its intended function. Check for damaged parts
and any other conditions that may affect the operation of this product. Replace or
repair damaged or worn parts immediately.
11. REPLACEMENT PARTS AND ACCESSORIES: When servicing, use only identi-
cal replacement parts. Only use accessories intended for use with this product.
Approved accessories are available from Harbor Freight Tools.
12. MAINTAIN THIS PRODUCT WITH CARE. Keep this product clean and dry for
better and safer performance.
13. MAINTENANCE: For your safety, service and maintenance should be performed
regularly by a qualified technician.
14. USE THE RIGHT TOOL FOR THE JOB. Do not attempt to force a small tool or
attachment to do the work of a larger industrial tool. There are certain applications
for which this tool was designed. It will do the job better and more safely at the rate
for which it was intended. Do not modify this tool, and do not use this tool for a
purpose for which it was not intended.
15. WARNING: The warnings, precautions, and instructions discussed in this manual
cannot cover all possible conditions and situations that may occur. The operator
must understand that common sense and caution are factors, which cannot be built
into this product, but must be supplied by the operator.

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 4
SPECIFIC PRODUCT WARNINGS AND PRECAUTIONS
1. CAUTION: Make sure to fill the Air Compressor with a premium quality, 30-weight,
non-detergent oil before each use. Running the Air Compressor with no oil or low
oil will cause damage to the equipment. Note: The oil reservoir has an optimal
capacity of 30 ounces of oil.
2. MAKE SURE ALL TOOLS AND EQUIPMENT USED WITH THE AIR COMPRES-
SOR ARE RATED TO THE APPROPRIATE CAPACITY. Do not use any tool or
equipment that does not operate at or above the PSI that the compressor’s regulator
is set to.
3. DRAIN AIR COMPRESSOR EVERY DAY. Do not allow moisture to build up inside
the Air Compressor. (See
“INSPECTION, MAINTENANCE, AND CLEANING”
section of this manual.)
4. MAINTAIN A SAFEWORKING ENVIRONMENT. Keep the work area well lit. Make
sure there is adequate surrounding workspace. Always keep the work area free of
obstructions, grease, oil, trash, and other debris. Do not use the Air Compressor in
areas near flammable chemicals, dusts, and vapors.
5. AVOID INJURY: Never direct the pressurized air stream at people or animals.
6. DO NOT ALTER OR REMOVE THE FACTORY SEALED PRESSURE RELEASE
VALVE (5A). (See Assy. Diagram A.)
7. DO NOT OPEN THE WATER DRAIN VALVE (10A) SOTHAT MORE THAN FOUR
THREADS ARE SHOWING. (See Assy. Diagram A.)
8. AN EXTENSION CORD MUST NEVER BE USEDWITHTHIS ITEM. Connecting
this item to an outlet through an extension cord MAY CAUSE ELECTRICAL
DAMAGETO THE MOTOR and could present a FIRE HAZARD. Longer air hoses
are typically safer and more effective than extension cords.
9. THIS UNIT REQUIRES A 230 VAC, UL LISTED, TWISTLOCK PLUG TO BE
INSTALLED BY A LICENSED TECHNICIAN BEFORE SETUP OR USE.
10. THIS COMPRESSOR MAY REQUIRE A DEDICATED ELECTRICAL CIRCUIT
AS THE AMPERAGE DRAW UNDER FULL LOAD COMBINED WITH USE OF
ANY OTHER ITEM MAY OVERLOAD YOUR CIRCUIT.
11. WARNING: This product contains or produces a chemical known to the State of
California to cause cancer and birth defects (or other reproductive harm).
(California Health & Safety Code § 25249.5,
et seq. )
12. People with pacemakers should consult their physician(s) before using this prod-
uct. Operation of electrical equipment in close proximity to a heart pacemaker could
cause interference to or failure of the pacemaker.

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 5
UNPACKING
When unpacking, check to make sure all the parts shown on the Parts Lists on pages 10,
and 11 are included. If any parts are missing or broken, please call Harbor Freight Tools at
the number shown on the cover of this manual as soon as possible.
OPERATING INSTRUCTIONS
NOTE: For additional references to the parts listed below, refer to the Assembly
Diagrams on pages 10, and 11.
To CheckThe Oil Level:
1. The Oil Window (20B) is used to determine if oil is needed. The oil level should
always be at the maximum level (red line on the Oil Window). (See Figure A, and
Assy. Diagram B.)
2. WHEN OPENING THE DIP STICK: Make sure to unscrew(do not pull) the Dip
Stick (14B) out. (See Figure A.)
3. If necessary, add a
premium quality, 30-weight, non-detergent oil into the Oil Fill
Hole until the level of oil reaches the maximum level as indicated on the Oil Window
(20B). The optimal capacity of the oil reservoir is 30 ounces. Do not overfill. Then
thread the Dip Stick back into the Oil Fill Hole, being careful not to strip the plastic
threads.
FIGURE A
Dip Stick (14B)
OilWindow (20B)
Front Cover (18B)
To Turn The Air Compressor On:
1. Check to make sure the Water Drain Valve (10A) is fully closed.
(See Assy. Diagram A.)

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 6
2. Pull on the Pressure Relief Valve (5A) briefly to ensure that it does not stick.
3. Turn the Air Flow Valve (6A) to its “OFF” position.
3. Connect the air hose (not provided) to the Air Flow Valve (6A) of the Air Compres-
sor. Then, connect the other end of the air hose to the pneumatic tool (not provided)
that is to be used.
4. To extend the life of your air tools and equipment, it is recommended to install
an oiler and water filter in series (available from Harbor Freight Tools) with the Air
Output Line of the Air Compressor. (See Figure B.)
5. Note: Always plug the Power Cord of the Air Compressor into a 230V electri-
cal source.
6. Pull up on the “ON/OFF” Power Switch (1A) to turn the Air Compressor on.
(Push down on the “ON/OFF” Power Switch to turn the Air Compressor off.)
7. Allow sufficient time for the Tank Pressure Gauge (4A) to indicate 80 PSI before
using the Air Compressor.
8. Turn the Air Flow Valve (6A) to its “ON” position to allow air to the pneumatic tool.
9. With the Air Compressor turned on, the operation is automatic and under the control
of the automatic switches inside the box under the Power Switch (1A).
NEVER open the power switch box or adjust the controls within.
To AdjustThe Air Output To The Pneumatic Tool:
1. NOTE: When adjusting the air pressure being forwarded to the pneumatic tool, you
will need to compare the pressure readings of both the Tank Pressure Gauge (3A)
and the Tool Pressure Gauge (4A). The reading on the Tank Pressure Gauge dic-
tates the maximum/minimum air pressure at which the Tool Pressure Gauge may
also be set.
2. With the Air Compressor running, and the air hose and pneumatic tool hooked up to
the Air Compressor, pull up on the Tool Pressure Adjuster (2A). Turn the Tool Pres-
TO
TOOL
AIR
COMPRESSOR
FIGURE B

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 7
sure Adjuster clockwise to increase the air output to the tool, up to the working air
pressure (115 PSI) as indicated on the Tank Pressure Gauge (3A). Never exceed
the maximum PSI for the tool being used or any component of the air system.
3. Turn the Tool Pressure Adjuster (2A) counterclockwise to decrease the air output
to the tool.
To Use The Tank Pressure Relief Valve:
1. The Tank Pressure Relief Valve Ring (5A) is used when decompression is needed
quickly and efficiently. It is also designed to release automatically if the compressor
pressurizes up to or beyond it’s safe limit.
2. To decompress the Air Tank (9A) pressure, press the “ON/OFF” Power Switch (1A)
down to turn off the Air Compressor.
3. Pull out on the Tank Pressure Relief Valve Ring (5A) to immediately release air
pressure in the Air Tank (9A).
To Empty Moisture From TheTank:
1. The Water DrainValve (10A) is located underneath the Air Tank (9A), and should be
used daily to release all trapped moisture through this valve. If this is not done,
condensation may cause Air Tank corrosion. (See Assy. Diagram A.)
2. WARNING: Do not open the Water Drain Valve (10A) so that more than four
threads are showing.
3. Push down on the “ON/OFF” Power Switch (1A) to turn off the Air Compressor. Then,
unplug the Air Compressor’s Power Cord from the electrical outlet.
4. You may wish to lay a pan under the drain to collect the dirty water trapped within.
Slowly and carefully unscrew (no more than four threads) the Water Drain Valve
(10A) until the compressed air and condensation begins to be released from the Air
Tank (9A). Allow sufficient time for all of the air and condensation to escape from
the Air Tank. Then, firmly retighten the Water Drain Valve.
IMPORTANT!
IF THE MOTOR STOPS UNEXPECTEDLY, the overload breaker may have
sensed an over-current condition, and stopped the motor to protect it. If this occurs,
shut off the pressure switch and wait at least 5 minutes. Release the air pressure in the
tank to ease restarting. Then press the breaker button to reset it, and turn on the pressure
switch. To help prevent this, ensure that this compressor is set up on a dedicated circuit
(one with no other equipment running on it), and that the distance from the compressor to
the circuit breaker panel is as short as possible (Extension cords should not be used, and
the outlet should not be far from the panel.).

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 8
INSPECTION, MAINTENANCE, AND CLEANING
1. WARNING: Always disconnect the Air Compressor from its electrical supply source
before performing any inspection, maintenance, or cleaning.
2. BEFORE EACH USE, inspect the general condition of the Air Compressor. Check
all air fittings for leaks. Check for loose screws, misalignment or binding of moving
parts, cracked or broken parts, damaged power cord and plug, and any other con-
dition that may affect the safe operation of this tool. If abnormal noise or vibration
occurs, immediately disconnect the Air Compressor from its electrical supply source
and have the problem corrected before further use.
Do not use damaged equipment.
3. DAILY: Check the Air Compressor oil level. If necessary, fill with a premium quality,
30-weight, non-detergent oil. NOTE: When checking the oil level, make sure to
unscrew(do not pull) the Dip Stick (14B). (See Assy. Diagram B.)
4. DAILY: Purge the Air Tank (9A) of all air and moisture to prevent corrosion. To do
so, slowly and carefully unscrew (no more than four threads) the Water Drain Valve
(10A) until the compressed air and condensation begins to be released from the Air
Tank. Allow sufficient time for all of the air and condensation to escape from the Air
Tank. Then, firmly retighten the Water Drain Valve. (See Assy. Diagram A.)
5. EVERY 100 HOURS OF USE: Clean the Air Filter (7A) with a mild solvent. Then,
dry and reattach the Air Filter. NOTE: Replace the Air Filter if it is too dirty to
properly clean. (See Assy. Diagram A.)
6. EVERY 500 HOURS OR 12 MONTHS: Drain and replace the old oil with new,
premium quality, 30-weight, non-detergent oil. When the Oil Drain (16A) is removed,
the old oil needs to be collected and disposed of in full accord with all applicable
waste disposal ordinances.
7. TO CLEAN: wipe with a damp cloth, using a mild detergent or mild solvent.
8. WHEN STORING: Keep the Air Compressor in a clean, dry location.
PLEASE READ THE FOLLOWING CAREFULLY
THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDEDTHE PARTS DIAGRAM IN THIS MANUAL AS A
REFERENCE TOOL ONLY. NEITHERTHE MANUFACTURER NOR DISTRIBUTOR MAKES ANY REPRESENTA-
TION OR WARRANTY OF ANY KINDTOTHE BUYER THAT HE OR SHE IS QUALIFIED TO MAKE ANY REPAIRS
TOTHE PRODUCT ORTHAT HE OR SHE IS QUALIFIEDTO REPLACE ANY PARTS OFTHE PRODUCT. IN FACT,
THE MANUFACTURER AND/OR DISTRIBUTOR EXPRESSLY STATES THAT ALL REPAIRS AND PARTS RE-
PLACEMENTS SHOULD BE UNDERTAKEN BY CERTIFIED AND LICENSED TECHNICIANS AND NOT BY THE
BUYER. 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 INSTALLA-
TION OF REPLACEMENT PARTS THERETO.

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 9
PARTS LIST A / ASSEMBLY DIAGRAM
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1A
2A
3A
4A
5A
7A
8A
9A
10A
12A
13A
14A
6A
15A
11A
16A
17A
18A 19A
20A
(Rear View with motor cover removed.)

SKU 93271 For technical questions, please call 1-800-444-3353. PAGE 10
NOTE: Some parts are listed and shown for illustration purposes only, and are not
available individually as replacement parts.
PARTS LIST B / ASSEMBLY DIAGRAM B
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B
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