U S GENERAL 93274 Stationary Air Compressor Instruction Manual

Air Superiority
Stationary
Air Compressor
Manual
For US General Models

For questions concerning this air compressor, please call: 1-866-869-3114.

SAFETY GUIDELINES – DEFINITIONS

Safety is a combination of common sense, staying alert and knowing how your compressor works.
Read this manual to understand this compressor.

DANGER
means if safety information is not followed someone will be seriously injured or killed
WARNING
means if safety information is not followed someone could be seriously injured or killed
CAUTION
means if safety information is not followed someone may be seriously injured or killed

IMPORTANT SAFETY INSTRUCTIONS

Save these instructions
Improper operation or maintenance of this product could result in serious injury and property damage. Read and understand all warnings and operation instructions before using this compressor.
Before using the air compressor

Things you should know
Air compressors are utilized in a variety of air system applications. Because air compressors and other components (hoses, connectors, air tools, spray guns, etc.) make up a high pressure pumping system, the following safety precautions should be observed at all
times.

Only persons familiar with these rules of safe operation should use the air compressor.

1. Read the instruction manual carefully before attempting to assemble, disassemble or operate your system. Be thoroughly familiar with the controls and the proper use of the equipment.
2.  Review and understand all safety instructions and operating procedures in this manual.
3.  Review the maintenance methods for this compressor (See “Maintaining Your Compressor” section).

Inspect your work area

1. Keep work area clean.
2. Cluttered areas and benches invite accidents.
   Floors must not be slippery from wax or dust.

Inspect your compressor

1. To reduce the risk of injury from accidental starting, turn switch off and disconnect the power before checking it.
2.  If any part is missing, bent or broken in any way, or any electrical part does not work prop erly, keep the compressor off and disconnected.
3.  Check hoses for weak or worn condition before each use, making certain all connections are secure. Do Not use if defect is found.
   WARNING
   Do not operate compressor if damaged during shipping, handling or use. Damage may result in bursting and cause injury or property damage.
   This compressor is Not designed for and should not be used in breathing air applications.
   DANGER

When installing or moving the compressor

WARNING
This compressor is extremely top heavy. The compressor must be bolted to the floor with vibration pads before operating to prevent  equipment damage, injury or death. Do Nottighten bolts completely as this may cause stress to the tank welds.
To reduce the risk of a dangerous environment

1. Keep work area well lit.

2. Operate compressor in a well-ventilated area free from flammable liquids and vapors.

3. Operate compressor in a ventilated area so that compressor may be properly cooled and the surrounding air temperature will not be more than 100°F.

4. Never use a compressor in a wet environment.

5. Protect material lines and air lines from damage or puncture. Keep hose and wires away from sharp objects, chemical spills, oil, solvents and wet floors.
   WARNING
   Do Not secure compressor with toggle bolts into drywall. Drywall sheeting or plaster will not support the weight of the compressor.

6. A minimum clearance of 18 inches between the compressor and a wall is required because objects could obstruct airflow.

7. The compressor should be located where it can be directly wired to a circuit breaker. The compressor should be wired by a qualified electrician.

8.  Never store flammable liquids or gases in the vicinity of an operating compressor.

9. Do Not locate the compressor air inlet near steam, paint spray, sandblasting areas or any other source of contamination. The debris could damage the motor and pump.

WARNING
Never use plastic (PVC) pipe for compressed air. Serious injury or death could result.
CAUTION
Never use the shipping skid for mounting the compressor.
NOTICE
This compressor is not intended for outdoor installation.
WARNING
Never install a shut off valve between the compressor pump and tank. Personal injury and/or equipment damage could occur.

Note: Tank Outlet Size: 1/2” NPT for Stock# 3848 & 93274 3/4” NPT for Stock# 90836

Before each use

Inspect your work area

1. Keep work area clean. Cluttered areas and benches invite accidents.
2. The floor must not be slippery from wax or dust.

Inspect your compressor

1. To reduce the risk of injury from accidental starting, turn the switch off and disconnect power.
2.  If any part is missing, bent or broken in any way, or any electrical part does not work properly, keep the compressor off and dis connect power. Do Not use if defect is found.
3.  Check hoses for weak or worn condition before each use, making certain all connect ions are secure. Do Not use if a defect is found.

Follow the safety precautions for electrical connections

1. Follow all local electrical and safety codes, as well as the National Electric Code (NEC) and the Occupational Safety and Health Act (OSHA).
2. Wiring and fuses should follow electrical codes, current capacity and be properly grounded.
3. Protect wires from contact with sharp objects.

CAUTION
All electrical connections should be made by a qualified electrician.

Plan ahead to protect your eyes, hands, face and ears

Dress for safety

1. Wear safety glasses (meeting ANSI Z87.1 or in Canada CSA Z94.3-99) and use hearing protection when operating the unit. Everyday glasses are not safety glasses.
2. Wear shoes to prevent shock hazards.
3. Tie back long hair.

Pay attention to your hands

WARNING
Keep fingers away from running compressorFast moving and hot parts may cause injury and/or burns.
WARNING
Be careful when touching the exterior of compressor, pump, motor and air lines; they may become hot enough to cause injury.
WARNING
Never operate the compressor without a beltguard. The compressor can start automatically without warning. Personal injury or property damage could occur from contact with moving parts.
CAUTION
The compressor may be hot even if the unit is stopped.
WARNING
Use of a mask or respirator per chemical manufacturers’ instructions may be necessary if there is a chance of inhaling toxic fumes.
Read mask and respirator instructions carefully. Consult a safety expert if you are not sure about the use of certain masks or respirators.

When operating

1. Do not exceed the pressure rating of any component of the system.
2. Release pressure within the system slowly to prevent flying dust and debris.
3.  If the equipment starts to abnormally vibrate, STOP the compressor immediately and check for the cause.

WARNING
Never change the safety valve or pressure switch settings. Keep safety valve free from paint and other accumulations. See compressor specification decal for maximum operating pressure. Do not operate with the pressure switch set higher than the maximum operating pressure.

Spraying precautions

WARNING
Never point a spray gun at yourself or any other person or animal. Accidental discharge may result in serious injury.
Reduce the risk of dangerous environment
WARNING
Extreme caution should be taken when spraying flammable liquids as the spark from a motor or pressure switch may cause a fire or explosion. Ample ventilation must be provided.
WARNING
Spray in a well ventilated area to keep fumes from collecting and causing serious injury and fire hazards.

1. Do Not spray in the vicinity of open flames or other places where a spark can cause ignition. Do Not smoke when spraying paint, insecticides, or other flammable substances.

Be informed about the materials you use

1. When spraying with solvents or toxic chemi cals, follow the instructions provided by the chemical manufacturer. Consult a safety expert if unsure about the use of masks or  respirators.
2.  If the material you intend to spray contains trichloreoethane and methylene chloride, do not use accessories that contain aluminum or galvanized materials, as these chemicals can react with galvanized components causing corrosion and weakening equipment. Use stainless steel accessories.

Perform these maintenance operations

1. Do regular maintenance; keep all nuts, bolts, and screws tight, to be sure equipment is in safe working condition.

2. Inspect tank yearly for rust, pin holes or any other imperfections that could cause it to become unsafe.
   WARNING
   NEVER attempt to repair or modify a tank! Welding, drilling or any other modification willweaken the tank resulting in damage from rupture or explosion. Always replace worn, cracked or damaged tanks.

3. Clean electrical equipment with an approved cleaning agent, such as a dry, non-flam mable cleaning solvent.

4. Drain tanks of moisture after each day’s use. If unit will not be used for awhile, it is best to leave the drain cock open until such time as it is to be used. This will allow moisture to completely drain out and help prevent corrosion of inside of tank.

5. Always disconnect from power source before working on or near a motor, or its connected load. If power disconnect point is out-of sight, secure it in the “OFF” position and tag it to prevent unexpected application of power.

WARNING
Disconnect power and depressurize system before servicing air compressor. Slightly open drain cock after shutting off compressor.
Daily
Check oil level at sight glass.
Drain moisture from tank.
Verify the pressure switch unloader is working by listening for a brief hissing sound when the compressor shuts off.
Visually check the compressor for loose parts, excessive noise or vibration.
Monthly
(Make sure the main power is off.) Check the belts for tension. Belts should not move up and down when the compressor runs and when stopped, should not have more than ½ in of play when depressed. Be careful not to over tighten belts during adjustment.
Remove and check air filter, replace if necessary. Change oil every 3 months or 300 hours. A compressor grade non-detergent oil should be used. (40 wt for 3848 and 30wt for Models 93274 and 90836).

WARNING LABELS

Find and read all warning labels found on the air compressor.

GLOSSARY OF TERMS

Air Filter
Porous element contained within a metal or plastic housing attached to the compressor cylinder head which removes impurity from the intake air of the compressor.
Air Tank
Cylindrical component which contains the compressed air.
Check Valve
Device which prevents compressed air from flowing back from the air tank to the compressor pump.
Electric Motor
Device which provides the rotational force necessary to operate the compressor pump.
Pressure Gauge
Device which shows the tank or regulated pressure of the compressed air.
Pressure Switch
Device which automatically controls the on/off cycling of the compressor. It stops the compressor when the cut-off pressure in the tank is reached and starts the compressorwhen the air pressure drops below the cut-in pressure.
PSI (Pounds per Square Inch)
Measurement of the pressure exerted by the force of air. The actual psi is measured by a pressure gauge on the compressor.
Pump
Device which produces the compressed air with a reciprocating piston contained within a cylinder.
Safety Valve
Device which prevents air pressure in the air tank from rising over a predetermined limit.
Thermal Overload Switch
Device, integrated into the electric motor winding, which automatically “shuts off” the compressor if the temperature of the electric motor exceeds a predetermined limit.

WIRING

WARNING
ALL ELECTRICAL WIRING SHOULD BE DONE BY A QUALIFIED ELECTRICIAN
General Information
Adequate wiring and motor protection should be provided for all stationary compressors. Wiring used for other machinery should not be used. A qualified electrician familiar with local electrical codes in your area should be used. Size supply wiring per NEC (National Electric Code) requirements.
WARNING
To reduce the risk of electrical hazards, fire hazards or damage to the compressor, use proper circuit protection. Your compressor is wired at the factory for operation using the voltage shown. Connect the compressor to a power source with the correct breaker size.
WARNING
Electrical connections must be properly grounded. Ground connections should be connected at the grounding screw.
CAUTION
Overheating, short circuiting and fire damage will result from inadequate wiring.

For Models 3848 & 93274

| 3848| 93274| 90836
---|---|---|---
Voltage| 230V / 1 ph| 230V / 1 ph| 230V / 1 ph
Full Load Amps| 16| 23| 32
Breaker Size| 30 amp| 40 amp| 60 amp

STARTING THE COMPRESSOR

Prior to actually running the compressor, check the following items:
Crankcase oil – Make sure the sight glass shows ½ full or slightly above.
Make sure all rags, tools, oil, etc. are away from the unit.
Open the air system to free it of any pressure.
Switch the compressor on for a few revolutions to make sure the rotation is correct.
Correct rotation is clockwise when facing the sight glass on the pump.
Operate the compressor for a few minutes unloaded (air system open) then allow the compressor to pump up. Make sure the electrical pressure switch properly switches off the compressor according to the setting desired. (130 psi for 3848, 165 for 93274, and 175 psi for 90836.)

CAUTION
Make sure the pressure in the tank does not exceed its rating. 3848 should operate at a maximum of 130 psi, 93274 should operate at a maximum of 165 psi, & 90836 at a maximum of 175 psi. If the pressure gauge indicates a pressure that is higher than these maximum pressures, shut off compressor immediately and call 1-866-869-3114.

TROUBLESHOOTING GUIDE

Low discharge pressure| 1. Compressor too small for application
2. Air leaks
3. Restricted intake air
4. Blown gasket(s)
5. Broken or misaligned valves| 1. Reduce air demand or use a compressor with more air capacity.
2. Listen for air leaks. Apply a soap solution     to all fittings and connections. Bubbles     will form at points of leakage. Tighten     or replace fittings or connections.
3. Clean or replace air filter.
4. Replace necessary gaskets.
5. Remove head and inspect for broken or     misaligned valves.  Replace valves, if
necessary.
CAUTION Install a new head gasket    each time head is removed
---|---|---
Excessive noise “knocking”| 1. Loose drive pulley or flywheel
2. Low on oil
3. Worn connecting rod or connecting rod bearing
4. Noisy check valve| 1. Tighten drive pulley or flywheel bolt.
2. Check for proper oil level.  Low or dirty     oil may cause bearing damage.
3. Replace connecting rod and/or connecting     rod bearings.
4. Replace check valve.
DANGER Do not remove check valve   with air pressure in tank
Excessive oil carryover| 1. Worn piston rings
2. Restricted intake air
3. Too much oil in compressor
4. Incorrect oil viscosity| 1. Replace with new piston rings.
2. Clean or replace air filter.
3. Drain oil to proper oil level.
4. Use a quality non-detergent 30 or 40wt
oil specified for each model (Page 4).
Water in tank and/or
discharge line| 1. Normal. Amount of water will
increase as humidity in the
air increases.| 1. Drain tank at least once per day.
2. Add an inline filter to reduce moisture in
in the air line.
Will not run or motor
hums| 1. Low voltage
2. Malfunctioning pressure switch
3. Malfunctioning check valve| 1. Check voltage with volt meter across both
legs of incoming power. Check reset button
on motor.
2. Repair or replace pressure switch.
3. Replace check valve or pressure switch.
DANGER Do not remove check valve with air pressure in tank
Breaker or reset repeatedly trips| 1. Incorrect breaker size
2. Low voltage
3. Malfunctioning motor
4. Loose electrical connections
5. Malfunctioning pressure switch
6. Malfunctioning check valve| 1. Make sure the breaker is sized properly.
See page 6 in this manual.
2. Check voltage with volt meter across both
legs of incoming power.
3. Replace motor.
4. Check all electrical connections.
5. Adjust or replace pressure switch.
6. Replace check valve.
DANGER Do not remove check valve  with air pressure in tank
Tank does not hold pressure when not running and shut off
valve is closed| 1. Malfunctioning check valve
2. Loose fittings or connections
3. Crack or pin hole in tank| 1. Replace check valve.
DANGER   Do not remove check valve with air pressure in tank
2. Tighten or replace fittings or connections.
3. Replace tank. Do not attempt to repair tank.

TROUBLESHOOTING GUIDE (Continued)

Pressure switch unloader
constantly leaking air| 1. Malfunctioning check valve| 1. Replace check valve if unloader bleeds
constantly.
**DANGER Do not remove check valve with air pressure in tank
---|---|---
Pressure switch not
unloading| 1. Malfunctioning pressure switch| 1. Replace pressure switch if it does not release
air pressure briefly when unit shuts off.
****DANGER** Do not remove pressure   switch with air pressure in      tank
Excessive vibration| 1. Improper installation
2. Loose belts
3. Misaligned flywheel or     drive pulley| 1. Make sure unit is mounted on a level surface     with vibration pads.
2. Replace belts.  Align and tighten properly.
3. Align flywheel and drive pulley.
Overheating| 1. Compressor too small for     application
2. Cooling surfaces dirty
3. Improper cooling| 1. Reduce air demand or use a compressor     with more air capacity.
2. Clean all cooling surfaces of dirt and dust.
3. Install compressor in an area with adequate     cool dry air.

Illustration Part Description

(2 Part Numbers)

| 6222019500| 1312100145| 1312100148
6214343100| 1312100146| 1312100150
| Drive Belts| 1312100134| 1312100133| 1312100140 (2)
| Drive Pulley| 1312100442| 1312100442| 1312100420
11| | | DP75HP1

*Part Numbers Subject to Change Without Notice Compressor Support: 866-869-3114

Air Superiority

LIMITED 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 this product is free from defects in materials and workmanship for a period of one year (3848) or two years (3847, 93274, and 90836) from date of purchase (90 days if used by a professional contractor or if used as rental equipment).
This warranty does not apply to damage due directly or indirectly to misuse, abuse, negligence or accidents; repairs or alterations outside our facilities; or 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. 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 the 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.

3491 Mission Oaks Blvd. PO Box 6009 Camarillo, CA 93011 (800)444-3353

Documents / Resources

| U S GENERAL 93274 Stationary Air Compressor [pdf] Instruction Manual
93274 Stationary Air Compressor, 93274, Stationary Air Compressor, Air Compressor, Compressor
---|---

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