Motomaster Air Compressor 5-gallon Owner's Manual
Model: 058-7949-6
For questions about missing or damaged parts, contact the Toll-Free Help Line: 1-888-942-MOTO (1-888-942-6686).
IMPORTANT: Ensure all users read safety rules and operating instructions carefully before use. Keep this manual for future reference.
Specifications
| Product number | 058-7949-6 |
| Peak horsepower | 2 HP |
| Tank size | 2 1/2 gallons (x2) |
| Air delivery (SCFM) @ 40 PSI | 5.1 |
| Air delivery (SCFM) @ 90 PSI | 4.1 |
| Cut-in pressure (PSI) | 95 |
| Maximum pressure (PSI) | 125 |
| Pump design | Cast-Iron cylinder, oil-lubricated, direct drive, single phase |
| Motor | Induction - 3400 RPM |
| Power | 120 V, 60 Hz, 15 A |
| Weight | 55 lb (25 kg) |
| Power cord | SJT 14 AWG / 78" (1.98 m) |
Safety Guidelines
This manual contains information for protecting personal safety and preventing equipment problems. Read and understand thoroughly before using the air compressor. Symbols indicate important information:
DANGER: POTENTIAL HAZARD THAT WILL RESULT IN SERIOUS INJURY OR LOSS OF LIFE
WARNING: POTENTIAL HAZARD THAT COULD RESULT IN SERIOUS INJURY OR LOSS OF LIFE
CAUTION: POTENTIAL HAZARD THAT MAY RESULT IN MODERATE INJURY OR DAMAGE TO EQUIPMENT
WARNINGS
- Risk of Explosion or Fire: Do not spray flammable liquids in confined areas. Sparks from the motor/pressure switch can ignite vapors. Do not smoke while spraying. Keep compressor away from spraying areas. Operate in a well-ventilated area.
- Risk of Electric Shock: Wiring must be done by a licensed electrician. Do not use outdoors in rain or on wet surfaces.
- Risk of Bursting: Rust weakens the tank. Drain condensed water after each use. Do not weld, drill, or modify the air tank. Replace leaking tanks immediately.
- Risk of Injury: Shut off and unplug the compressor before servicing. Bleed all pressure. Do not operate with shrouds removed. Contact with moving parts can cause injury.
- Risk of Bursting: Do not exceed the maximum pressure rating. Relieve pressure in the hose before attaching/detaching accessories.
- Risk of Bursting: Do not adjust the pressure switch or relief valve. They are factory preset. Tampering can cause injury or damage.
- Risk of Burns: Pump and manifold get hot. Do not touch running parts. Allow to cool before servicing. Keep children away.
- Risk to Breathing: Read paint/material labels. Use a respirator mask. Do not inhale compressed air directly.
- Risk of Eye Injury: Wear ANSI Z87.1 approved safety goggles. Do not point nozzles at people or body parts.
CAUTIONS
- Pull the pressure relief valve ring daily to ensure it functions.
- Locate the compressor in a well-ventilated area, at least 12" (31 cm) from walls.
- Protect air hose and power cord from damage. Inspect weekly and replace if necessary.
- Always wear hearing protection.
- Do not operate if the compressor is not stable.
- Do not operate on rooftops or elevated positions where it could fall or tip over.
Know Your Air Compressor
This Motomaster Air Compressor is ideal for automotive applications like fastening, greasing, and engine cleaning. It features a 5-gallon twin tank design, a 2 HP (peak) induction motor for quiet operation, and a cast-iron, oil-lubricated pump for reliability. It includes a 25' coil hose and attachment fittings.
Compatible Compressor & Air Tool Guidelines: Ensure air tools match the compressor's volume, pressure, and delivery rate. Using tools that require more air than the compressor can deliver may void the warranty.
Extension Cords: Avoid if possible. If used, it must be 12 AWG minimum, no longer than 50' (15 m), 3-wire with a grounding plug, connected to a 3-holed outlet.
Air System Setup:
- A filter-regulator-lubricator is recommended near the tool.
- If no filter-regulator-lubricator, add 2-6 drops of compressor oil to air-powered tools before use.
- Keep the air filter clean; a dirty filter reduces tool performance.
- Install quick connectors on tools and quick couplers on the hose for better performance.
- Ensure all air supply connections are sealed to prevent air loss.
Diagram Description (Figure 4): The diagram shows a typical air system setup including a Tool, Quick Coupler, Air Hose, Lubricator, Filter, Regulator (0-8.5 bar), Cut-off valve, and the Air Compressor.
Component Identification:
The air compressor has the following labeled components:
- A: Electric Motor (not visible)
- B: Air Compressor Pump
- C: Pressure Switch
- D: Pressure Relief Valve
- E: Air Pressure Regulator
- F: Tank Pressure Gauge
- G: Regulated Pressure Gauge
- H: Air Line Outlet (for 1/4" NPT air hose)
- I: Air Tank Drain Valve
- J: Air Tank
- K: Power Cord (115V/15A, grounded)
Standard Equipment: 25' recoil hose with 1/4" NPT connector and quick connector.
Before You Start - Assembly Instructions
- Unpack the air compressor. Inspect for transit damage and file a claim immediately if found. The carton should contain the air compressor, accessories, and owner's manual.
- Check the identification label to ensure the correct model and pressure rating.
- Position the air compressor:
- Near a grounded electrical outlet.
- At least 12" (31 cm) from walls in a clean, well-ventilated area for airflow and cooling.
- In cold climates, store in a heated building to prevent motor starting issues and condensation freezing.
- On a floor or hard, level surface for proper drainage.
- Connect an air hose to the compressor hose outlet (as shown in Figure 2).
- Refer to the unit's identification label for voltage and amperage requirements.
Use a Dedicated Circuit
For best performance and reliable starting, plug the compressor into a dedicated circuit close to the fuse box or breaker. The compressor uses the full capacity of a typical 15 amp circuit. Other devices on the same circuit can cause starting failure or tripping. Low voltage or overloaded circuits can lead to sluggish starting.
Note: A circuit breaker is recommended. If using fuses, use dual element time delay fuses (Buss Fusetron type "T" only).
Before You Start - Break-in Period of the Pump
Note: The pump is shipped WITHOUT oil. Add break-in oil to the pump's oil nozzle before starting. Change break-in oil after 8 hours of operation. Use premium compressor oil; SAE 10W-30 is recommended for general use. Dispose of used oil environmentally.
- Check the oil level in the pump sight glass (between A1 and A2). Do not overfill or underfill.
- Turn the pressure switch to the OFF position (B).
- Open the tank drain valve (C) by turning counter-clockwise.
- Plug in the power cord.
- Turn the pressure switch to the ON position (B). The unit will start. Let it run for 30 minutes to break in internal parts. If it doesn't operate properly after 30 minutes, shut down and contact Product Service.
- After 30 minutes, turn the pressure switch to the OFF position.
- Close the tank drain valve by turning clockwise.
- Turn the pressure switch to the ON position. The unit will start, fill the tank to cut-out pressure, and stop. The pressure switch will automatically restart the motor as compressed air is used.
Diagram Descriptions:
- A: Oil sight glass indicating oil level (between A1 and A2).
- B: Pressure switch with OFF and ON positions.
- C: Tank drain valve, shown with OPEN (counter-clockwise) and CLOSE (clockwise) directions.
- D: A fitting, possibly a quick connector.
Operating Instructions
Daily Start-Up
If the pump was transported or tilted, let it sit upright for approximately 10 minutes before starting.
- Check the oil sight glass to ensure the oil level is correct.
- Turn the pressure switch to the OFF position.
- Close the tank drain valve.
- Plug in the power cord.
WARNING: High temperatures are generated by the motor and pump. Do not touch the compressor while running. Allow it to cool before handling or servicing. Keep children away.
- Turn the pressure switch to the ON position.
- Adjust the pressure regulator to the working pressure of the tool. To decrease pressure, turn the knob counter-clockwise past the setting and then clockwise to the desired pressure. Do not exceed the tool's operating pressure.
Shut-Down Procedure
- Switch the pressure switch to the OFF position.
- Unplug the power cord.
- Reduce pressure in the tank through the outlet hose or by pulling the relief valve ring (D) to keep it open.
- Open the drain valve (C) to allow moisture to drain from the tank.
CAUTION: Escaping air and moisture can propel debris, causing eye injury. Wear safety goggles when opening the drain valve.
Maintenance
WARNING: Shut off, unplug, and relieve all air pressure before performing any service.
Regular maintenance ensures trouble-free operation. Inspect items regularly:
| ITEM | DESCRIPTION/REASON | SERVICE INTERVAL |
|---|---|---|
| Drain the tank. | Condensation accumulates in the tank. Drain daily to prevent tank corrosion. Wear protective goggles. Relieve pressure before draining. Crucial in cold conditions to prevent freezing. | Daily |
| Check the oil. | Check oil level in the pump sight glass (must be within the red circle). Do not overfill or underfill. | Daily |
| Check the relief valve. | Pull/activate the relief valve daily to ensure proper operation and clear obstructions. | Daily |
| Clean the air filter. | A dirty filter reduces performance. Clean frequently or replace. Foam filters should be cleaned in warm, soapy water. | Weekly |
| Test for leakages. | Check all connections for tightness. Leaks reduce performance. Spray suspected areas with soapy water; bubbles indicate leaks. Repair or reseal faulty components. Do not over-tighten. | Monthly |
| Storage. | For long-term storage, clean dust/debris with an air blow gun. Coil power cord. Clean filter element/housing. Drain tank moisture. Pull pressure relief valve to release pressure. Cover the unit. | N/A |
Troubleshooting
WARNING: If any symptoms appear, stop use immediately. Only authorized service centers should perform repairs. Disconnect power and air supply before adjustments.
Note: Troubleshooting problems may have similar causes and solutions.
| PROBLEM | POSSIBLE CAUSE | SOLUTION |
|---|---|---|
| Compressor motor will not run or start. | Power cord not plugged in. | Plug cord into grounded outlet. |
| Pressure Switch in "OFF" position. | Turn switch to "ON" or "AUTO" position. | |
| Wrong gauge wire or length of extension cord. | Check specifications for proper gauge wire and cord length. | |
| Motor thermal overload switch is tripped. | Turn compressor off, wait until motor is cool, then check motor circuit breaker. | |
| Fuse is blown or circuit breaker is tripped. | Replace fuse or reset circuit breaker. Check for proper fuse amperage. Check for low voltage conditions. Disconnect other electrical appliances from circuit or operate on its own designated circuit. | |
| Air tank pressure exceeds preset pressure switch limit. | Motor will start automatically when tank pressure drops below cut-in pressure. | |
| Check valve is stuck open. Electrical connections are loose. Possible defective motor, capacitor or check valve. Low Voltage. | Remove and clean or replace. Contact authorized service centre or store. Contact authorized service centre or store. Check power source (outlet or generator) with volt-meter. | |
| Motor hums but cannot run, or runs slowly. | Unit is plugged into an extension cord. | Remove extension cord. Tip: Use a longer hose instead of an extension cord. |
| Shorted, or open motor winding. | Contact authorized service centre or store. Motor replacement may be required. | |
| Check valve is defective. | Contact authorized service centre or store. Parts may require replacement. | |
| Fuses blow/circuit breaker trips repeatedly. | Incorrectly sized fuse or circuit circuit is overloaded. | Check for proper fuse or breaker, use time-delay fuse of the proper size. Disconnect other electrical appliances from circuit or operate on its own branch circuit. |
| Circuit is overloaded. | Disconnect other electrical appliances from circuit or operate on a dedicated circuit. | |
| Unit is plugged into an extension cord. | Remove extension cord. Tip: Use a longer hose instead of an extension cord. | |
| Check valve is defective. | Contact authorized service centre or store. Parts may require replacement. | |
| Motor runs continuously when in the Auto mode. | Pressure switch does not shut off motor when air compressor reaches cut-out pressure and safety relief valve activates. | Move the pressure switch to the OFF position. If motor does not shut off, unplug. Contact authorized service centre or store. |
| Air compressor is not large enough. | Check accessory air requirements. If higher than compressor's CFM/pressure, a larger compressor is needed. | |
| Thermal overload protector cuts out repeatedly. | Low voltage. | Check power source (outlet or generator) with volt-meter. |
| Clogged Air Filter. | Clean or replace air filter. | |
| Lack of proper ventilation/room temperature too high. | Relocate compressor to a cool, dry, well-circulated area. | |
| Regulator does not regulate pressure. | Unit is plugged into an extension cord. Dirt-covered cooling surfaces. | Remove extension cord. Allow compressor to cool down. Clean cooling surfaces thoroughly. |
| Dirty or damaged regulator internal parts. | Replace regulator. Contact authorized service centre or store. | |
| Low pressure or not enough air. | Fittings leak. | Check fittings with soapy water. Tighten or reseal. Do not over-tighten. |
| Tank drain valve is open. | Close drain valve. | |
| Restricted air intake. | Clean or replace air filter element. | |
| Prolonged excessive use of air. | Decrease amount of air used. | |
| Hole in air hose. Tank leaks. Valve leaks. | Check and replace if necessary. Replace unit immediately. Check and replace worn parts. | |
| Excessive moisture in discharge air. | Excessive water in air tank. | Drain Tank. |
| High humidity. | Move compressor to an area of lower humidity or install an in-line air filter. |
Parts Schematic & Parts List
The following table lists the components of the air compressor:
| Key# | Description | Qty | Key# | Description | Qty |
|---|---|---|---|---|---|
| 1 | Drain valve | 1 | 17 | Brass Nipple | 1 |
| 2 | Bolt | 4 | 18 | Copper Tube | 1 |
| 3 | Rubber foot | 4 | 19 | Handle sleeve | 1 |
| 4 | Tank | 1 | 20 | Pump assembly | 1 |
| 5 | Panel | 1 | 21 | Motor assembly | 1 |
| 6 | Nut | 4 | 22 | Shroud | 1 |
| 7 | Bolt | 7 | 23 | Transfer tube | 1 |
| 8 | Tube | 1 | 24 | Check valve | 1 |
| 9 | Pressure gauge | 2 | 25 | Nut | 4 |
| 10 | Quick connector | 2 | 26 | Spring Washer | 4 |
| 11 | Regulator | 1 | 27 | Flat Washer | 4 |
| 12 | Safety valve | 1 | 28 | Bolt | 2 |
| 13 | Pressure switch | 1 | 29 | Motor mount | 1 |
| 14 | Elbow | 1 | 30 | Cross-head screw | 2 |
| 15 | Power cord | 1 | 31 | Hex Head Screw | 1 |
| 16 | Air filter | 1 |
Motomaster Limited Warranty
This Motomaster product is guaranteed for three (3) years from the date of original retail purchase against defects in materials and workmanship.
If returned with proof of purchase within the warranty period, the product will be repaired or replaced at the manufacturer's option. The manufacturer will cover repair/replacement costs.
Warranty Conditions and Limitations:
- A bill of sale verifying purchase date is required.
- Warranty does not cover wear/breakage due to abuse, misuse, accidental damage, neglect, improper installation, operation, or maintenance, or use for industrial/commercial/rental purposes.
- Warranty does not cover normal wear and tear or expendable parts expected to become inoperative.
- Warranty does not cover routine maintenance items (fuel, lubricants, filters, adjustments, etc.).
- Warranty does not cover damage from unauthorized repairs or attempted repairs.
- Warranty does not cover reconditioned or refurbished products unless specified in writing.
- Warranty does not cover products with non-manufacturer parts or unauthorized alterations.
- Warranty does not cover normal exterior finish deterioration (scratches, dents, paint chips, corrosion).
- Warranty does not cover component parts identified as another company's product.
Additional Limitations
Warranty applies only to the original purchaser and is non-transferable. The retailer or manufacturer is not liable for indirect, incidental, consequential, or exemplary damages.
Notice to Consumer
This warranty grants specific legal rights, and consumers may have other rights varying by province. These provisions do not limit or exclude statutory warranties.
Imported by Mastercraft Canada, Toronto, Canada M4S 2B8.
