Central Pneumatic 94667 User manual

21 GALLON
CAST IRON VERTICAL OIL-LUBRICATED
AIR COMPRESSOR
Model 94667
OPERATING INSTRUCTIONS
Visit our website at: http://www.harborfreight.com
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
Copyright©2006 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. Diagrams within this manual may not be drawn proportionally. Due to continuing
improvements, actual product may differ slightly from the product described herein. Tools required for
assembly and service may not be included.
For technical questions or replacement parts, please call 1-800-444-3353.
Revised Manual 10d

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 2
SPECIFICATIONS TABLE
Maximum Air Pressure 115 PSI
Air Tank Capacity 21 Gallons
Air Flow Capacity 4.9 SCFM at 90 PSI
7 SCFM at 40 PSI
Motor 3 HP Working / 5 HP Peak
120 Volt / 60 Hz / 12 A / 1-Phase
Required Circuit Minimum 20 Amp *Dedicated
Pump Stage Single
Air Outlet Size 1/4” - 18 NPT
Accessories Air Intake Filter; Air Hose Coupler
*A dedicated circuit is used only for a single load, for this compressor. Other loads on the circuit must be
disconnected or turned off when the compressor is plugged in.
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. KEEP IDLE EQUIPMENT. When not in use, tools and equipment should be kept
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
reexes are impaired while taking drugs. If there is any doubt, do not attempt to
use this product.
5. USE EYE AND HAND PROTECTION. Wear ANSI-approved safety impact
goggles and heavy-duty work gloves when using this product. ANSI-approved
safety impact eyeglasses and heavy-duty work gloves are available from Harbor
Freight Tools.
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 elbows.
REV 06l; 07c; 09c, 10a
#233060

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 3
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
identical 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 qualied 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 94667 For technical questions, please call 1-800-444-3353. PAGE 4
SPECIFIC PRODUCT WARNINGS AND PRECAUTIONS
1. WARNING: Make sure to ll the Air Compressor with a premium quality,
30-weight, non-detergent compressor 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. WHEN CHECKING THE OIL LEVEL: Make sure to unscrew (do not pull) the
Breather Valve (14B) out. (See Figure C, and Assy. Diagram B.)
3. MAKE SURE ALL TOOLS AND EQUIPMENT USED WITH THE AIR
COMPRESSOR ARE RATED TO THE APPROPRIATE CAPACITY. Do not use
any tool or equipment that does not operate from 0 to 115 PSI.
4. DO NOT LEAVE COMPRESSOR UNATTENDED FOR AN EXTENDED PERIOD
WHILE PLUGGED IN. Unplug compressor after working.
5. KEEP COMPRESSOR WELL-VENTILATED. Do not cover compressor during
use.
6. 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.)
7. MAINTAIN A SAFE WORKING 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 ammable chemicals, dusts, and vapors.
8. AVOID INJURY: Never direct the Air Flow Valve (6A) at people or animals. (See
Assy. Diagram A.)
9. DO NOT ALTER OR REMOVE THE FACTORY SEALED PRESSURE
RELEASE VALVE (5A). (See Assy. Diagram A.)
10. DO NOT OPEN THE WATER DRAIN VALVE (10A) SO THAT MORE THAN
FOUR THREADS ARE SHOWING. (See Assy. Diagram A.)
11. AN EXTENSION CORD MUST NEVER BE USED WITH THIS ITEM.
Connecting this item to an outlet through an extension cord MAY CAUSE
ELECTRICAL DAMAGE TO THE MOTOR and could present a FIRE HAZARD.
12. 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.
13. 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.)REV10c

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 5
TO EXTEND THE LIFE OF YOUR AIR TOOLS AND EQUIPMENT, it is
recommended to install an oiler and water lter in series (available from Harbor
Freight Tools) with the Air Output Line of the Air Compressor.
OPERATING INSTRUCTIONS
NOTE: For additional references to the parts listed below, refer to the Assembly
Diagrams on pages 9, and 10.
To Check The 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 C,
and Assy. Diagram B.)
UNPACKING
When unpacking, check to make sure all the parts shown on the Parts Lists on
pages 9, and 10 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.
IMPORTANT! This compressor is shipped with the oil ll plug removed and without
oil. The oil ll plug is attached to the power cord as a reminder to add oil to the
crankcase. Add oil to the proper level as explained below and secure the oil ll
plug before use.
REV 07i
14. WARNING: People with pacemakers should consult their physician(s) before
using this product. Operation of electrical equipment in close proximity to a heart
pacemaker could cause interference to or failure of the pacemaker.

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 6
2. If necessary, add a premium quality, 30-weight, non-detergent compressor 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 overll. Then thread the Breather Valve back into the Oil Fill Hole, being
careful not to strip the plastic threads. (See Figure C, and Assy. Diagram B.)
To Turn The Air Compressor On:
1. Check to make sure the Water Drain Valve (10A) is fully closed.
2. 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
Compressor. Then, connect the other end of the air hose to the pneumatic tool
(not provided) that is to be used.
4. Note: Always plug the Power Cord of the Air Compressor into a 115 V~
electrical source (±10% maximum variation).
5. Rotate the “ON/OFF” Power Switch (1A) to the horizontal position to turn the Air
Compressor on. (Rotate the “ON/OFF” Power Switch (1A) to the vertical position
to turn the Air Compressor off.)
6. Allow sufcient time for the Tank Pressure Gauge (4A) to indicate 80 PSI before
using the Air Compressor.
7. Turn the Air Flow Valve (6A) to its “ON” position to allow air to the pneumatic tool.
FIGURE C
Breather Valve (14B)
Oil Window (20B)
Front Cover (18B)

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 7
8. NOTE: 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 Adjust The 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
dictates 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
Pressure 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).
3. Turn the Tool Pressure Adjuster (2A) counterclockwise to decrease the air output
to the tool, down to the minimum rated pressure (0 PSI) as indicated on the Tank
Pressure Gauge (3A).
To Use The Tank Pressure Relief Valve:
1. The Tank Pressure Relief Valve Ring (5A) is used when decompression is needed
quickly and efciently.
2. To decompress the Air Tank (9A) pressure, rotate the “ON/OFF” Power Switch (1A)
up to the vertical position 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 Air And Condensation From The Tank:
1. The Water Drain Valve (10A) is located underneath the Air Tank (9A), and should
be used daily to release all trapped moisture through this valve. The Water Drain
Valve will also eliminate condensation that may cause Air Tank corrosion.
2. WARNING: Do not open the Water Drain Valve (10A) so that more than four
threads are showing.
3. Rotate the “ON/OFF” Power Switch (1A) up to the vertical position to turn off the Air
Compressor. Then, unplug the Air Compressor’s Power Cord from the electrical
outlet.
4. 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 sufcient time for all of the air and condensation to escape from
the Air Tank. Then, rmly retighten the Water Drain Valve.

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 8
INSPECTION, MAINTENANCE, AND CLEANING
1. CAUTION: 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 ttings for leaks. Check for loose screws, misalignment or binding of moving
parts, cracked or broken parts, damaged power cord and plug, and any other
condition 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, ll with a premium quality,
30-weight, non-detergent compressor oil. NOTE: When checking the oil level, make
sure to unscrew (do not pull) the Breather Valve (14B).
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 sufcient time for all of the air and condensation to escape from the Air
Tank. Then, rmly retighten the Water Drain Valve.
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.
6. EVERY 500 HOURS OR 12 MONTHS: Replace the old oil with new, premium
quality, 30-weight, non-detergent compressor oil.
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 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 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 INSTALLATION OF REPLACEMENT PARTS THERETO.
Reference: Overload Switch (35B)
The overload breaker will trip if an over-current condition is sensed, stopping the
motor. 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.

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 9
PARTS LIST A / ASSEMBLY DIAGRAM A
Part Description Qty.
1A ON/OFF Power Switch 1
2A Tool Pressure Adjuster 1
3A Tank Pressure Gauge 1
4A Tool Pressure Gauge 1
5A Pressure Release Valve 1
6A Air Flow Valve 1
7A Air Filter 1
8A Air Flow Lid 1
9A Air Tank 1
10A Water Drain Valve 1
Part Description Qty.
11A Quick Release Coupler 1
12A Rubber Wheel with Bolt 2
13A Washer 2
14A Nut 2
15A Fitting 1
16A Oil Drain Plug with Gasket 1
17A Foot 2
18A Unloader Valve 1
19A Polyurethane Unloader Tube 1
20A Copper Air Tube 1
REV 07b; 07f; 10d
1A
2A
4A
5A
7A
8A
9A
10A
12A
13A 14A
15A
11A
16A
17A
18A 19A
20A
(Rear View with motor cover removed.)
3A
6A
12A

SKU 94667 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 avail-
able individually as replacement parts.
PARTS LIST B / ASSEMBLY DIAGRAM B
Part Description Qty.
1B Bolt 4
2B Cylinder Case 1
3B Gasket 1
4B Valve Seat 1
5B Gasket 1
6B Cylinder 1
7B Compression Ring 2
8B Oil Scraping Ring 1
9B Piston 1
10B Gasket 1
11B Piston Pin 1
12B* End Cover 1
13B Crankshaft Retainer 2
14B Breather Valve 1
15B Connecting Rod 1
16B Gasket 1
17B Bolt 6
18B Front Cover 1
Part Description Qty.
19B Gasket 1
20B Oil Window 1
21B Crankshaft Bolt 1
22B Crankshaft 1
23B Crankshaft Case 1
24B* Stator 1
25B* Bearing 2
26B* Armature 1
27B Start Capacitor, 70 mF±5% bMK 1
28B Radiating Fan Wheel 1
29B Retainer Ring 1
30B Bolt 4
31B Screw 2
32B Radiating Cover 1
33B* Seal Washer 1
34B Motor Assembly 1
35B Overload Switch 1
36B Run Capacitor, 50 mF±5% bMK 1
*Not available individually. Must be ordered as entire Motor Assembly (See part #34B).

SKU 94667 For technical questions, please call 1-800-444-3353. PAGE 11
LIMITED 1 YEAR / 90 DAY WARRANTY
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 for a period
of one year from date of purchase that the tank is free of defects in materials and work-
manship (90 days if used by a professional contractor or if used as rental equipment).
Harbor Freight Tools also warrants to the original purchaser, for a period of ninety days
from date of purchase, that all other parts and components of the product are free from
defects in materials and workmanship. This warranty does not apply to damage due di-
rectly or indirectly to misuse, abuse, negligence or accidents, repairs or alterations out-
side our facilities, 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 limita-
tion 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 veries 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 specic legal rights and you may also have other rights
which vary from state to state.
3491 Mission Oaks Blvd. • PO Box 6009 • Camarillo, CA 93011 • [phone]