Craftsman 921.16474 User Manual (English)

Questions and Answers:

M
michaelgloverAug 14, 2025
Why does my Craftsman 921.16474 Air Compressor trip the circuit breaker?
- A
  Ashley ThomasAug 14, 2025
  Excessive current draw can trip the circuit breaker due to several reasons. It could be due to low voltage or motor overload. Ensure your power supply is adequate and the compressor is on a dedicated circuit. If you're using an extension cord, try operating the compressor without it. If the compressor is connected to a circuit protected by a fuse, use dual element time delay fuses (Buss Fusetron type “T” only). The drive belt tension may also be too tight; readjust the belt tension. Another possible cause is restricted air passages. Inspect and replace the transfer tubes or the check valve.
S
Sarah HarrisAug 17, 2025
What to do if my Craftsman Air Compressor has low discharge pressure?
- S
  Steven CarterAug 17, 2025
  If your air compressor has low discharge pressure, there are several potential causes. You may have air leaks, so tighten or replace any leaking fittings or connections, being careful not to overtighten them. Another reason could be a restricted air intake; in this case, clean or replace the air filter element(s).
M
Margaret AndersonAug 21, 2025
Why is there oil in the discharge air from my Craftsman Air Compressor?
- C
  Crystal SampsonAug 21, 2025
  Oil in the discharge air can occur due to several reasons. It may be caused by a restricted air intake, so clean or replace the air filter element(s). Another possibility is that the oil level is too high; reduce it to the proper level.
M
montgomerychristinaAug 25, 2025
What to do if my Craftsman 921.16474 Air Compressor stalls?
- C
  Cindy MasonAug 25, 2025
  If your Craftsman Air Compressor stalls, it could be due to low voltage to the motor, ensure you furnish adequate power. Another cause could be a bad check valve.
J
Jake JacksonAug 27, 2025
What to do if my Craftsman 921.16474 Air Compressor won’t start in cold temperatures?
- M
  Maria WilsonAug 27, 2025
  If your compressor won’t start in cold temperatures, it could be due to too much back pressure in the tank; open the petcock when starting the motor. It might also be because of 40W oil in the crankcase; use synthetic, non-detergent air compressor oil instead. The compressor itself might be too cold, so move it to a warmer location.
A
Andrea HarrisAug 31, 2025
How to prevent my Craftsman 921.16474 Air Compressor from overheating?
- K
  krausejulieAug 31, 2025
  Overheating can occur due to poor ventilation. Relocate the compressor to an area with cool, dry, well-circulated air, ensuring it is at least 12 inches from the nearest wall. Dirty cooling surfaces can also cause overheating, so clean all cooling surfaces thoroughly. Restricted air passages can also cause overheating. Inspect and replace transfer tubes or the check valve.
P
peter36Sep 3, 2025
Why is my Craftsman 921.16474 pump knocking?
- D
  Danielle CurrySep 3, 2025
  A knocking sound in the compressor pump can be caused by a loose motor pulley or pump flywheel; retighten the pulley and flywheel and check their alignment. It could also indicate a low oil level in the pump crankcase, so ensure you keep the oil at the proper level at all times.
B
Barbara WernerSep 6, 2025
How to reduce excessive belt wear on my Craftsman Air Compressor?
- C
  Cody BurkeSep 6, 2025
  Excessive belt wear can be attributed to a pulley being out of alignment; realign the pulley with the compressor flywheel. Improper belt tension can also cause this issue; readjust the tension. Additionally, a pulley that wobbles should be replaced, and you should check for a damaged crankshaft or flywheel.
T
Tammy DavidsonSep 9, 2025
Why is air leaking through the bleeder valve of my Craftsman Air Compressor after it shuts off?
- S
  Stephanie OchoaSep 10, 2025
  Air leaking through the bleeder valve after the compressor shuts off is often due to a dirty or defective check valve. Replace or clean the check valve.

Craftsman 921.16474 Specifications

General

Model	921.16474
Type	Portable
Max Pressure	150 PSI
Power Source	Electric
Voltage	120V
Amperage	15 Amps

Summary

Important Safety Instructions

Fire, Explosion, and Bursting Hazards

Covers risks from flammable liquids, sparks, and tank modifications. Ensure ventilation.

Electrical and Mechanical Hazards

Addresses shock risks from wet conditions and injury from moving parts. Keep guards in place.

Health and Personal Safety

Includes respiratory protection, eye protection, burn prevention, and avoiding operation under influence.

Important Safety Instructions Continued

Operational and Environmental Safety

Covers unattended operation, breathing air use, stable positioning, and hearing protection.

Cautionary Measures

Daily draining, ventilation, transport, storage, and electrical cord protection.

Glossary of Terms

Technical Definitions

Explains terms like CFM, PSI, Cut-in/Cut-out pressure, Well-ventilated, Dedicated circuit.

Overview

Key Compressor Components

Identifies electric motor, pump, pressure switch, and tank as key components.

Assembling the Compressor

Initial Setup and Placement

Includes unpacking, inspection, handle installation, and proper placement for ventilation.

Connecting Air Hose

Connects the air hose to the quick connect for operation.

Compressor Controls

Pressure Management Components

Covers pressure switch, safety valve, release valve, and tank/regulated pressure gauges.

Output Pressure Adjustment

Details the air pressure regulator and quick connect for tool connection.

Motor Reset and Wiring

Motor Reset Switch

Procedure to reset the motor after overload. Ensure guards are in place.

Dual Voltage Operation Note

Information on 115/230V motors and the need for a licensed electrician for conversion.

Electrical Power Requirements

Circuit and Extension Cord Guidelines

Use dedicated circuits and avoid extension cords; specify gauge and length if used.

Grounding Instructions

Ensure proper grounding for safety. Do not modify the plug. Use correct outlet.

Operating Instructions

Break-In of the Pump

Run the compressor for 30 minutes to break in internal parts. Follow specific steps.

Daily Start-Up Procedure

Steps for starting the compressor daily, including checks and adjustments.

Shutdown Procedure

Steps to safely turn off and prepare the compressor for storage or next use.

Maintenance

General Maintenance Precautions

Shut off, unplug, and relieve pressure before any service. Regular maintenance ensures trouble-free operation.

Draining the Tank

Drain moisture daily to prevent tank corrosion. Wear protective eyewear.

Checking and Changing Oil

Instructions for checking oil level and changing oil using synthetic, non-detergent oil.

Maintenance Continued

Drive Belt Tension and Pulley Alignment

Procedures for adjusting belt tension and aligning pulleys for efficient operation and belt life.

Drive Belt Replacement

Steps to remove and replace the drive belt, ensuring proper centering and tension.

Check Valve Maintenance

Instructions for cleaning or replacing the check valve to ensure proper function.

Maintenance Continued

Air Filter Cleaning

Clean or replace the air filter regularly to maintain performance and prevent contamination.

Relief Valve Check and Leak Testing

Daily check of relief valve operation and testing connections for leaks.

Storage Instructions

Prepare for prolonged storage by cleaning, disconnecting power, and draining the tank.

Troubleshooting

Common Problems and Solutions

Addresses issues like circuit tripping, stalling, low pressure, knocking, overheating, and starting problems.

Parts Drawing / Esquemá de las Piezas

Parts List

Lists components with part numbers, quantities, descriptions, and Spanish/French translations.

Parts Drawing / Esquemá de las Piezas

Component Identification

Diagrams illustrating components for vertical and horizontal tank models.

Parts List / Lista de las Piezas

Component Details

Detailed list of parts including part numbers, descriptions, and Spanish/French translations.

Capacitor Information

Details on start and run capacitors for different motor types.

Pump Assembly Details

Pump Components and Torque Specs

Diagram of pump assembly with torque specifications for head and carrier bolts.

Pump Specifications

Provides weight, oil capacity, RPM limits, and maximum ambient temperature.

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28 pages

Craftsman 921.16474 User Manual

Table of Contents

Questions and Answers:

Craftsman 921.16474 Specifications

Summary

Important Safety Instructions

Fire, Explosion, and Bursting Hazards

Electrical and Mechanical Hazards

Health and Personal Safety

Important Safety Instructions Continued

Operational and Environmental Safety

Cautionary Measures

Glossary of Terms

Technical Definitions

Overview

Key Compressor Components

Assembling the Compressor

Initial Setup and Placement

Connecting Air Hose

Compressor Controls

Pressure Management Components

Output Pressure Adjustment

Motor Reset and Wiring

Motor Reset Switch

Dual Voltage Operation Note

Electrical Power Requirements

Circuit and Extension Cord Guidelines

Grounding Instructions

Operating Instructions

Break-In of the Pump

Daily Start-Up Procedure

Shutdown Procedure

Maintenance

General Maintenance Precautions

Draining the Tank

Checking and Changing Oil

Maintenance Continued

Drive Belt Tension and Pulley Alignment

Drive Belt Replacement

Check Valve Maintenance

Maintenance Continued

Air Filter Cleaning

Relief Valve Check and Leak Testing

Storage Instructions

Troubleshooting

Common Problems and Solutions

Parts Drawing / Esquemá de las Piezas

Parts List

Parts Drawing / Esquemá de las Piezas

Component Identification

Parts List / Lista de las Piezas

Component Details

Capacitor Information

Pump Assembly Details

Pump Components and Torque Specs

Pump Specifications

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