Craftsman 921.16476 Owner's Manual

Owner’s Manual

CAUTION:
Before using this product,
read this manual and follow
all its Safety Rules and
Operating Instructions.

Sears Brands Management Corporation, Hoffman Estates, IL 60179 U.S.A.
www.craftsman.com

5/7/2010
Part No. 200-2794

AIR COMPRESSOR

Oil Lubricated
Single Stage
Belt Drive, Electric

60 Gallon Vertical

Model No. 921.16476

• Safety Instructions

• Installation & Operation

• Maintenance & Storage

• Troubleshooting Guide

• Parts List

• Español, p. 18

• Français, p. 29

2 200-2794

WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

SPECIFICATION CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

SAFETY GUIDELINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4

GLOSSARY OF TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

TYPICAL INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

COMPRESSOR CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . .7

ELECTRICAL POWER REQUIREMENTS . . . . . . . . . . . . . . .7

OPERATING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . .8

MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-11

SERVICE INTERVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

TROUBLESHOOTING CHART . . . . . . . . . . . . . . . . . . . . . . .12

PARTS DRAWINGS AND PARTS LISTS . . . . . . . . . . . . .13-17

TABLE OF CONTENTS

CRAFTSMAN ONE YEAR FULL WARRANTY

FOR ONE YEAR from the date of purchase, this product is warranted against any defects in material
or workmanship. Defective product will receive free repair or free replacement if repair is unavailable.

For warranty coverage details to obtain repair or replacement, visit the web site: www.craftsman.com
This warranty does not cover the air filter or drive belt, which are expendable parts that can wear out

from normal use within the warranty period.
This warranty is void if this product is ever used while providing commercial services or if rented to

another person.
This warranty gives you specific legal rights, and you may also have other rights which vary from

state to state.
Sears Brands Management Corporation, Hoffman Estates, IL60179 U.S.A.

WARRANTY

SPECIFICATION CHART

MODEL NO.

RUNNING

H.P.

TANK CAPACITY

GALLONS

VOLTAGE/

AMPS/PHASE

APPROXIMATE

CUT-IN

PRESSURE

APPROXIMATE

CUT-OUT

PRESSURE

921.16476

(WLB3106016)

3.1 Vert. 60 (228 Liters) 230/15/1

120

(8,27 bar)

150

(10,34 bar)

3200-2794

SAFETY GUIDELINES

IMPORTANT SAFETY INSTRUCTIONS

The following information relates to protecting YOUR SAFETY and PREVENTING EQUIPMENT PROBLEMS. To help you recognize
this information, we use the following symbols. Please read the manual and pay attention to these sections.

– A POTENTIAL HAZARD THAT WILL CAUSE SERIOUS INJURY OR LOSS OF LIFE.

– A POTENTIAL HAZARD THAT COULD CAUSE SERIOUS INJURY OR LOSS OF LIFE.

– A POTENTIAL HAZARD THAT MAY CAUSE MODERATE INJURY OR DAMAGE TO

EQUIPMENT.

WARNING:

DANGER:

CAUTION:

RISK OF FIRE OR EXPLOSION. Never spray flammable liquids in a confined area. It is normal for the motor and pressure switch to

produce sparks while operating. If sparks come into contact with vapors from gasoline or other
solvents, they may ignite, causing fire or explosion. Always operate the compressor in a
well–ventilated area. Do not smoke while spraying. Do not spray where sparks or flame are
present. Keep compressor as far from spray area as possible. Store flammable materials in a
secure location away from compressor. Equip the area of operation with a fire extinguisher.

RISK OF BURSTING. Do not weld, drill or modify the air tank of this compressor. Welding or modifications on the air

compressor tank can severely impair tank strength and cause an extremely hazardous condition.
Welding or modifying the tank in any manner will void the warranty. If tank develops a leak, replace
it immediately with a new tank or replace the entire compressor.

RISK OF ELECTRICAL SHOCK. Never use an electric air compressor outdoors when it is raining or on a wet surface, as it may

cause an electric shock. Failure to provide adequate grounding to this product could result in
serious injury or death from electrocution. Make certain that the electrical circuit to which the
compressor is connected provides proper electrical grounding, correct voltage and adequate fuse
protection.

RISK OF INJURY. This unit starts automatically. ALWAYS shut off the main power disconnect, and bleed all pressure

from the system before servicing the compressor, and when the compressor is not in use. Do not
use the unit with the shrouds or belt guard removed. Serious injury could occur from contact with
moving parts. Stay alert and watch what you are doing when operating the compressor. Do not use
the compressor while tired or under the influence of drugs or alcohol.

RISK OF BURSTING. Check the manufacturer’s maximum pressure rating for air tools and accessories. Compressor

outlet pressure must be regulated so as to never exceed the maximum pressure rating of the tool.
Relieve all pressure through the hose before attaching or removing accessories. Never use
compressor to inflate small low pressure objects such as children’s toys, footballs, basketballs, etc.

RISK OF BURNS. High temperatures are generated by the pump and manifold. To prevent burns or other injuries, DO

NOT touch the pump, manifold or transfer tube while the pump is running. Allow them to cool
before handling or servicing. Keep children away from the compressor at all times. Do not reach
around protective shrouds or attempt to maintenance until unit has been allowed to cool.

RISK TO
BREATHING/INHALATION
HAZARD..

Always wear MSHA/NIOSH approved, properly fitting face mask or respirator and work in a
well ventilated area when using tools that generate dust. Some dust created by power

sanding, grinding, drilling and other construction activities contains chemicals known (to the State
of California) to cause cancer, birth defects or other reproductive harm. Some examples of these
chemicals are:

• lead from lead-based paints

• crystalline silica from bricks and cement and other masonry products

• arsenic and chromium from chemically treated lumber.

RISK TO BREATHING. Be certain to read all labels when you are spraying paints or toxic materials, and follow the safety

instructions provided on the lable or safety sheets for the materials you are spraying. Use a
MSHA/NIOSH approved respirator mask if there is a chance of inhaling anything you are spraying.
Read all instructions and be sure that your respirator mask will protect you. Work in an area with
good cross ventilation.

RISK OF EYE INJURY. Always wear ANSI Z87.1 approved safety goggles when using an air compressor. Never point any

nozzle or sprayer toward a person, animal or any part of the body. Equipment can cause serious
injury if the spray penetrates the skin.

RISK OF BURSTING. •Do not adjust the tank safety valve for any reason. Doing so voids all warranties. The relief valve

has been pre-set at the factory for the maximum pressure of this unit. Personal injury and /or
property damage may result if the relief valve is tampered with.

•Do not use plastic or pvc pipe for compressed air. Use only galvanized steel pipe and fittings for
compressed air distribution lines.

WARNING:

4 200-2794

IMPORTANT SAFETY INSTRUCTIONS

RISK OF FIRE. Unattended operation of this compressor could result in personal injury or property damage. To

reduce the risk of fire, do not allow the compressor to operate unattended. Always disconnect
electrical power by turning the pressure switch to off and drain the tank daily or after each use.

RISK TO BREATHING. Air obtained directly from the compressor should never be used to supply air for human

consumption. The air stream may contain carbon monoxide, toxic vapors, or solid particles from
tank. Breathing these contaminant's can cause serious injury or death. In order to use air produced
by this compressor for breathing, suitable filters and in-line safety equipment must be properly
installed. In-line filters and safety equipment must be properly installed. In-line filters and safety
equipment used in conjunction with the compressor must be capable of treating air to all applicable
local and federal codes prior to human consumption.

RISK OF INJURY Always operate the compressor in a stable secure position to prevend accidental movement of the

unit. Never operate the compressor on a table, workbench, roof or other elevated position. Use
additional air hose to reach high locations.

RISK TO HEARING. Always wear hearing protection when using an air compressor. Failure to do so may result in

hearing loss.

The interconnect cord on this product contains lead, a chemical known to the State of California to
cause cancer, and birth defects or other reproductive harm. Wash hands after handling.

NOTE: ELECTRICAL WIRING. Refer to the air compressor’s serial label for the unit’s voltage and amperage requirements. Ensure

that all wiring is done by a licensed electrician, in accordance with the National Electrical code.

WARNING:

CAUTION:

Drain the moisture from the tank on a daily basis. A clean, dry tank will help prevent corrosion.
Pull the tank safety valve ring daily to ensure that the valve is functioning properly, and to clear the valve of any possible obstructions.

To provide proper ventilation for cooling, the compressor must be kept a minimum of 12 inches (31 cm) from the nearest wall, in a
well–ventilated area. Restricting any of the compressor ventilation openings will cause overheating and could cause fire, never place
objects against or on top of compressor.

Fasten the compressor down securely if transporting is necessary. Pressure must be released from the tank before transporting.
Protect the air hose and interconnect cord from damage and puncture. Inspect them weekly for weak or worn spots, and replace if

necessary.
To reduce the risk of electric shock, do not expose to rain. Store indoors.

On oil-lubed compressors, oil can leak or spill and could result in fire or breathing hazard. Oil leaks will damage paint, carpet or other
surfaces in vehicles or trailers. Always place the compressor on a protective mat when transporting to protect against damage to
vehicle from leaks. Remove compressor from vehicle immediately upon arroval at your destination.

To prevent damage to tank and compressor on stationary models, the tank must be shimmed so the pump base is level within 1/8” to
distribute oil properly. All feet must be supported, shimming where necessary, prior to attaching to the floor. Fasten all feet to floor. We
also recommend the use of vibration pads (094-0137) under tank feet.

CFM: Cubic feet per minute; a unit of measure of air flow.
PSI: Pounds per square inch; a unit of measure of air pressure.
Cut-in pressure: While the motor is off, air tank pressure drops

as you continue to use your accessory. When the tank pressure
drops to factory set low pressure point, the motor will restart
automatically. The low pressure at which the motor automatically
restarts is called “cut-in” pressure.

Cut-out pressure: When an air compressor is turned on and
begins to run, air pressure in the air tank begins to build. It builds
to the factory set high pressure point before the motor
automatically shuts off, protecting your air tank from pressure
higher than its capacity. The high pressure at which the motor

shuts off is called “cut-out” pressure.
Well-ventilated: Means of providing fresh air in exchange for

dangerous exhaust or vapors.
Dedicated circuit: An electrical circuit reserved for the exclusive

use of the air compressor.

GLOSSARY OF TERMS

This compressor was shipped with oil in the pump
crankcase. Check oil before operating the air compressor,
see Check Oil under Maintenance.

1. Unpack the air compressor. Inspect the unit for damage. If
the unit has been damaged in transit, contact the carrier
and complete a damage claim. Do this immediately
because there are time limitations to damage claims.

The carton should contain:

• air compressor

• operator/parts manual

2. Check the compressor’s serial label to ensure that you
have received the model ordered, and that it has the
required pressure rating for its intended use.

3. Locate the compressor according to the following
guidelines:

a. For optimum performance, locate the compressor close

to the power panel, as specified in ELECTRICAL
POWER REQUIREMENTS, and as close as possible to
the place where the air will be used. This ensures
maximum power to the compressor and maximum air
pressure to the tool. If both of these conditions

cannot be met, it is better to locate the compressor
close to the power panel, and use a longer air hose
to reach the usage area.

b. The flywheel side of the compressor must be at least

12 inches (31 cm) from any wall or obstruction, in a
clean, well-ventilated area, to ensure sufficient air
flow and cooling.

c. In cold climates, locate the compressors in a

heated building when not in use. This will reduce
problems with lubrication, motor starting and freezing
of water condensation.

d. Remove the compressor from the shipping pallet and

place it on the floor or a hard, level surface. The
compressor must be level to ensure proper
lubrication of the pump and good drainage of the
moisture in the tank.

The shipping pallet is not designed as a
base for an operating compressor. Operating the
compressor while it is on the pallet will void your
warranty.

e. To prevent damage to tank and pump, the tank must be

shimmed so the pump is level within 1/8” per lineal foot
maximum to distribute oil properly. Fasten to floor and
NEVER force tank feet to floor without shims when
tightening. We also recommend the use of vibration
pads (094-0137) under tank feet (E).

4. Connect an air hose (not included) to the compressor.

5200-2794

The basic components of the air compressor are the electric

motor, pump, pressure switch and tank (see Fig. 1).

The electric motor (see A) powers the pump. The electric
motor is equipped with an overload protector to help prevent
possible motor burnout. If the motor becomes overheated, the
overload protector will shut it down. Should this occur, allow the
motor to cool for 10-15 minutes, then press (never force) the
motor reset switch to restart the motor.

The pump (see B) compresses the air and discharges it into
the tank.

The tank (see C) stores the compressed air.

The pressure switch (see D) shuts down the motor when
the tank reaches a pre-set "cut-out" pressure. As compressed air
is used and the tank drops to a pre-set "cut-in" pressure, the
switch restarts the motor automaticallly, and the pump resumes
compressing air.

OVERVIEW

BASIC AIR COMPRESSOR COMPONENTS

Fig. 1

Fig. 2

ASSEMBLY

ASSEMBLING THE COMPRESSOR

B

D

A

C

E

CAUTION:

6 200-2794

TYPICAL INSTALLATION

Risk of bursting, resulting in injury.

Never use plastic pipe for compressed air.

Never use lubricator for paint spraying

or similar applications.

WARNING:

CAUTION:

Air dryers and after coolers

An air dryer or aftercooler is installed directly in the air line.

Moisture removal and air filtration

As the air cools, moisture will condense in the lines. This
moisture must be removed before it reaches the tool being used.
To remove this moisture, run the main air line downhill to a

moisture trap and drain. Air/water filters should also be installed
in the positions shown.

Air pressure regulation

The air pressure gauge on the pressure switch measures air
pressure inside the tank, not pressure in the air line. Install an air
regulator in the drop line for each tool, to regulate air pressure to
that tool. Never exceed the maximum pressure rating of the tool.

Air lubrication

Install an air lubricator only for those tools requiring
lubrication. Do not use a lubricator for paint spraying or similar
applications. The oil will contaminate the paint and ruin the job.

Shut–off valves

Install shut–off valves in each drop line, to isolate the tool
and its accessories for servicing. You can also install a bypass
line around an accessory.

A Air flow
B Feeder line
C Drain leg
D Moisture trap with drain
E Non–lubricated supply line
F 1/4 turn valve
G Bypass
H Air dryer or aftercooler

J Line filter
K Drip tee with drain
L Air/water filter with petcock

M Regulator
N Lubricator

P Quick coupler

R Air hose to tool

T Flexible air line

7200-2794

Main Power Disconnect

Install a main power disconnect switch in the power line to
the compressor, near the compressor’s location. It is operated
manually, but when it is in the ON position, the compressor will
start up or shut down automatically based on air demand.
ALWAYS operate this switch to OFF when the compressor is not
being used.

Pressure switch (see A)

This switch turns on the compressor. It is operated manually,
but when in the ON position, it allows the compressor to start up
or shut down automatically, without warning, upon air demand.
ALWAYS set this switch to OFF when the compressor is not
being used, and before unplugging the compressor.

For your safety, tank pressure is preset

within the switch and must never be tampered with.

This switch must not be adjusted by the operator; doing so
will void the warranty. The pressure switch controls the level of air
pressure in the tank by automatically starting and stopping the
motor, as required to maintain the factory preset pressure level.

The pressure switch also automatically bleeds pressure from
the pump head when the pump stops. This feature eliminates
back pressure in the pump, ensuring easier starting.

Tank Safety Valve (see B)

Used to allow tank pressure to escape into the atmosphere.

If the pressure switch does not shut off the compressor at it’s
“cut-out” pressure setting, the safety valve will protect against
high pressure by releasing tank pressure at it’s factory set
pressure (slightly higher than the pressure switch “cut-out”
setting). To operate manually, pull the ring on the valve to relieve
air pressure in the tank.

Pressure Release Valve (see C)

The pressure release valve (located on the bottom of the
pressure switch), is designed to release compressed air from the
compressor head and outlet tube when the compressor reaches
“cut-out” or is shut off. The pressure valve allows the motor to
restart freely. When the motor stops running, air will be heard
escaping from this valve for a few seconds. No air should be
heard leaking when the motor is running or after brief release
after reaching “cut-out” pressure.

Tank Pressure Gauge (see D)

This gauge measures
the pressure level of the
air stored in the tank. It is
not adjustable by the
operator, and does not
indicate line pressure.

Fig. 3

COMPRESSOR CONTROLS

Ensure that all guards and shrouds are in
place before pressing the reset switch to restart the
motor.

If the motor shuts down because of overload, wait 10–15
minutes so the motor can cool down, then press (NEVER force)
the reset switch (see D) to restart the motor (see Fig. 4).

Refer to the air compressor’s serial label for the unit’s voltage
and amperage requirements. Ensure that all wiring is done by a
licensed electrician, in accordance with the National Electrical
Code. Use electrical conduit to protect the wiring.

For best performance and reliable starting, the air
compressor must be installed on a dedicated circuit, as
close as possible to the electrical power panel. Provide circuit

breaker or fuse protection at your main power panel. Use time
delay fuses on the circuit, because the compressor will
momentarily draw several times its specified amperage when first
started.

Install a main power disconnect switch in the line from the
panel to the compressor. The main power disconnect switch must
be located near the compressor, for ease of use and safety.
When turned OFF, the main power disconnect switch shuts off all
power to the compressor. When it is turned ON, the compressor
will start and stop automatically, controlled by the pressure
switch.

Low voltage will cause difficult starting or an overload. Low
voltage can be caused by a low supply voltage from the local
power company, other equipment running on the same line, or
inadequate wiring. If any other electrical devices are drawing from
the compressor’s circuit, it may fail to start.

Low voltage to the compressor can be caused by a supply
wire of insufficient gauge for the distance between the
compressor and the power source. The longer the distance, the
larger the wire gauge (lower the number) must be, to overcome
the inherent voltage loss caused by the wire resistance. Refer to
the National Electrical Code to determine proper wire size for
your circuit.

If the wiring is not adequate, the input voltage will drop by 20
to 40 volts at startup. Low voltage or an overloaded circuit can
result in sluggish starting that causes the circuit breaker to trip,
especially in cold conditions.

This product must be connected to a grounded, metallic,
permanent wiring system, or an equipment - grounding terminal
or lead on the product.

Fig. 4

MOTOR RESET SWITCH

WARNING:

A

D

B

D

(Measures pressure in
tank, not line pressure)

WARNING:

ELECTRICAL POWER REQUIREMENTS

ELECTRICAL WIRING

MAIN POWER PANEL

MAIN POWER DISCONNECT SWITCH

LOW VOLTAGE PROBLEMS

GROUNDING INSTRUCTIONS

C

8 200-2794

1. Make sure the power is connected at the power panel.

2. Check the oil level in the pump (see “Checking the Oil” in the
maintenance section).

3. Open the petcock (see C).

Escaping air and moisture can
propel debris that may cause eye injury. Wear safety
goggles when opening petcock.

4. Turn ON the main power disconnect switch. Turn the
pressure switch to the AUTO position (see B). The motor
should start. Allow the compressor to run for 30 minutes, to
break in the internal parts.

NOTE: After about 30 minutes, if the unit does not operate

properly, SHUT DOWN IMMEDIATELY, and contact a
Sears or other qualified service center. DO NOT return
the unit to the store where it was purchased.

5. Shut OFF the main power disconnect. Close the petcock
(see D). Connect your air hose(s) to the tank outlet(s).

NOTE: As compressed air is used, the pressure switch will

restart the motor automatically to supply more
compressed air to the tank.

1. Check the oil level in the pump (see “Checking the Oil” in the
maintenance section).

2. Make sure the main power disconnect switch is shut OFF.

3. Close the tank petcock (see D).

4. Turn ON the main power disconnect switch. Turn the
pressure switch to the AUTO position (see B). The pump will
start filling the tank with air. When the air pressure in the
tank reaches the level preset at the factory, the pressure
switch will turn off the electric motor. As air is used and the
pressure level in the tank drops, the pressure switch will start
the motor and the pump will begin refilling the tank.

High temperatures are generated
by the pump. To prevent burns or other injuries, DO
NOT touch the pump or transfer tube while the pump
is running. Allow it to cool before handling or
servicing. Keep children away from the compressor
at all times.

NOTE: If the unit does not operate properly, SHUT DOWN

IMMEDIATELY, and contact a Sears or other qualified
service center.

1. Turn the pressure switch to the OFF position (see A).

2. Shut OFF the main power disconnect switch.

3. Reduce pressure in the tank through the outlet hose. You
can also pull the tank safety valve ring (see E) and keep it
open to relieve pressure in the tank.

Escaping air and moisture can
propel debris that may cause eye injury. Wear safety
goggles when opening petcock.

4. Open the petcock (see C) to allow moisture to drain from

the tank.

OPERATING INSTRUCTIONS

BREAK-IN OF THE PUMP

DAILY START-UP

SHUTDOWN

WARNING:

CAUTION:

OPEN

CLOSE

C

D

E

CAUTION:

9200-2794

MAINTENANCE

To avoid personal injury, always shut off
and unplug the compressor and relieve all air pressure
from the system before performing any service on the air
compressor.

Regular maintenance will ensure trouble–free operation.

Your electric powered air compressor represents high–quality
engineering and construction; however, even high–quality
machinery requires periodic maintenance. The items listed below
should be inspected on a regular basis

Drain the moisture from the tank (for instructions, see

“Shutdown” in the operating instructions section).

Condensation will accumulate in
the tank. To prevent corrosion of the tank from the
inside, this moisture must be drained at the end of
every workday. Wear protective eyewear.

To check the oil level in the pump, unscrew the dipstick (D)
and wipe off oil. Screw the dipstick all the way in and then
unscrew. The pump oil level should be between between add
(see C) and full (see B). Replace the dipstick. Do not overfill
or under fill.

NOTE: Use synthetic, non-detergent air compressor oil.

Remove the oil plug (see A) and drain the oil until it slows to
a drip, then close. Add compressor oil (approx. 18 oz.) until it is
between full (see B) and add (see C) when the dipstick (see D) is
screwed completely into the hole. Never overfill or underfill the
pump.

NOTE: The compressor is pre-filled with synthetic oil. Use
synthetic, non-detergent air compressor oil.

NOTE: Drive belt tensioning and pulley alignment are done
at the same time. They are discussed separately for clarity.

This unit starts automatically.
ALWAYS shut off the main power disconnect, and
bleed all pressure from the system before servicing
the compressor, and when the compressor is not in

use. Do not use the unit with the shrouds or belt
guard removed. Serious injury could occur from
contact with moving parts.

Proper belt tension and pulley alignment must be maintained
for maximum drive efficiency and belt life. The correct tension
exists if a deflection (see A) of 1/2” (13 mm) occurs by placing 10
lbs. (4.6 kg) of force (see B) midway between the motor pulley
and the pump flywheel (See Fig. 8). This deflection can be
adjusted by the following procedure. The pulley should be
carefully aligned with the flywheel, and all setscrews should be
kept tight.

1. Remove the front of the beltguard by removing the 5 screws

using a Phillips head screwdriver.

2. Loosen the motor mounting bolts.

3. Shift the motor to the point where the correct deflection exists

(A & B).

4. Retighten the motor mounting bolts to 130-180 in.-lbs.

5. Check to ensure that the tension remained correct.

6. Reinstall the belt guard. All moving parts must be guarded.

NOTE: Drive belt tensioning and pulley alignment are done at
the same time. They are discussed separately for clarity.

This unit starts automatically.
ALWAYS shut off the main power disconnect, and
bleed all pressure from the system before servicing
the compressor, and when the compressor is not in
use. Do not use the unit with the shrouds or belt
guard removed. Serious injury could occur from
contact with moving parts.

MAINTENANCE

WARNING:

DRAINING THE TANK

CHECKING THE OIL

CHANGING THE OIL

WARNING:

DRIVE BELT TENSION ADJUSTMENT

Fig. 8

B = Full
C = Add

Fig. 7

WARNING:

PULLEY ALIGNMENT

WARNING:

10 200-2794

MAINTENANCE

NOTE: Once the motor pulley has been moved from its factory

set location, the grooves of the flywheel and pulley must
be aligned to within 1/16” to prevent excessive belt wear.

To check pulley alignment, remove the belt guard and place
a straightedge (see A) against the pump flywheel (see B) (See
Fig. 9). Measure and record the distance from the straightedge to
the edge of the drive belt at point C. Then measure the distance
from the straightedge to the edge of the drive belt again at points
D and E. Both distances should be the same as at point C. If D or
E are different from C, there is a misalignment which must be
corrected before the compressor is run. To correct a pulley
misalignment, use the following procedure.

1. Remove the front of the beltguard by removing the 5 screws

using a Phillips head screwdriver.

2. Loosen the motor mounting bolts.

3. Loosen the setscrew on the motor pulley.

4. Align the motor pulley with the pump flywheel (C-D-E must

be equal ).

5. Retighten the motor pulley setscrew to 85-90 in.-lbs.

6. Adjust the proper belt tension.

7. Retighten the motor mounting bolts to 130-180 in.-lbs.

8. Reinstall the belt guard. All moving parts must be

guarded.

This unit starts automatically.
ALWAYS shut off the main power disconnect, and
bleed all pressure from the system before servicing
the compressor, and when the compressor is not in
use. Do not use the unit with the shrouds or belt
guard removed. Serious injury could occur from
contact with moving parts.

1. Remove the front of the beltguard by removing the 5 screws
using a Phillips head screwdriver.

2. Loosen the motor mounting bolts.

3. Shift the motor towards the pump to the point where the belt
can be easily removed and installed.

4. Remove and replace belt. NOTE: The belt must be centered
over the grooves on the flywheel and motor pulley.

5. Shift the motor back to the point where the correct deflection
exists (see “Drive Belt Tension Adjustment”).

6. Retighten the motor mounting bolts to 130-180 in.-lbs.

7. Check to ensure that the tension remained correct.

8. Reinstall the belt guard. All moving parts must be guarded.

This unit starts automatically.
ALWAYS shut off the main power disconnect, and
bleed all pressure from the system before servicing
the compressor, and when the compressor is not in
use. Do not use the unit with the shrouds or belt
guard removed. Serious injury could occur from
contact with moving parts.

1. Turn air compressor off,
remove the power cord
from the outlet or lock
out the power supply
and relieve all the air
pressure from the tank
(refer to "Shutdown" in
Operating Instructions).
Make sure the
compressor has cooled
down before servicing.

2. Using the appropriately
sized wrench, loosen the
compression nuts
(A) on the check valve
(B) and pump head (C).
Remove the transfer
tube (D).

3. Making note of the
orientation for reassembly, unscrew the check valve from
the tank (counterclockwise) using a 7/8” open end wrench.

4. Using a pencil or screwdriver, carefully
push the valve disc up and down. If the
valve disc does not move freely up and
down, the check valve needs to be
cleaned or replaced.

5. Clean the check valve with warm soapy
water and make sure to dry thoroughly
before reinstalling. If the disc valve still
does not move freely up and down, it will
need to be replaced.

6. Apply thread sealant to the check valve
threads and reinstall into the tank by
turning clockwise.

7. Replace the transfer tube and tighten
compression nuts.

8. Perform the “Break-in of the pump” procedure in the
Operating Instructions to make sure there are no leaks and
the check valve is working properly.

Fig. 9

TO REPLACE OR CLEAN CHECK VALVE

WARNING:

DRIVE BELT REPLACEMENT

WARNING:

11200-2794

MAINTENANCE

SERVICE INTERVAL

Perform the following maintenance at the intervals indicated below.

Daily or after

each use

Every 100

operating hours

Inspect air filter (clean or replace as necessary)

•

Check pump oil level

•

Change pump oil (Use synthetic, non-detergent air compressor oil)

•

Operate the tank safety valve

•

Check belt tension

•

Drain tank

•

Check and tighten all bolts (do not over tighten)

•

A dirty air filter will reduce the compressor’s performance and
life. To avoid any internal contamination of the pump, the filter
should be cleaned frequently, and replaced on a regular basis.
Felt filters should be cleaned in warm, soapy water, rinsed, and
allowed to air dry before reinstallation. Paper filters should be
replaced when dirty. Do not allow the filter to become filled with
dirt or paint. If the filter becomes filled with paint, it should be
replaced. Direct exposure to dirty conditions or painting areas will
void your warranty.

Pull the tank safety valve daily to ensure that it is operating
properly and to clear the valve of any possible obstructions.

Check that all connections are tight. A small leak in any of
the hoses, transfer tubes, or pipe connections will substantially
reduce the performance of your air compressor. If you suspect a
leak, spray a small amount of soapy water around the area of the
suspected leak with a spray bottle. If bubbles appear, repair or
replace the faulty component. Do not over tighten any
connections.

Before storing the compressor for a prolonged period, use an
air blow gun to clean all dust and debris from the compressor.
Disconnect the power cord and coil it up. Pull the tank safety
valve to release all pressure from the tank. Drain all moisture
from the tank. Clean the filter element and filter housing; replace
the element if necessary. Drain the oil from the pump crankcase
and replace it with new oil. Cover the entire unit to protect it from
moisture and dust.

CLEANING THE AIR FILTER

CHECKING THE RELIEF VALVE

TESTING FOR LEAKS

STORAGE

12 200-2794

Note: Troubleshooting problems may have similar causes and solutions.

TROUBLESHOOTING

PROBLEM POSSIBLE CAUSE SOLUTION
Excessive current draw

trips circuit breaker or
motor reset switch

Low voltage/motor overload Check that power supply is adequate and that compressor is on a

dedicated circuit.

Drive belt too tight Readjust belt tension.
Restricted air passages Inspect and replace transfer tubes or the check valve, (see “To replace

or clean check valve” in the maintenance section).

Compressor stalls Low voltage to motor Furnish adequate power.

Bad check valve Replace the check valve (see “To replace or clean check valve” in the

maintenance section).

Seized pump Contact a Sears or other qualified service center.

Low discharge pressure Air leaks Tighten or replace leaking fittings or connections. Do not overtighten.

Leaking valves Contact a Sears or other qualified service center.
Restricted air intake Clean or replace air filter element(s).
Blown gaskets Contact a Sears or other qualified service center.
Worn piston rings or cylinder Contact a Sears or other qualified service center.

Compressor pump
knocking

Loose motor pulley or pump
flywheel

Retighten pulley and flywheel. Check alignment.

Low oil level in pump crankcase Keep oil at proper level at all times.
Excess carbon on valves or top of

piston

Contact a Sears or other qualified service center.

Oil in discharge air Worn piston rings or cylinder Contact a Sears or other qualified service center.

Restricted air intake Clean or replace the air filter element(s).
Oil level too high Reduce to proper level.

Overheating Poor ventilation Relocate compressor to an area with cool, dry, well circulated air, at

least 12 in. from nearest wall.

Dirty cooling surfaces Clean all cooling surfaces thoroughly.
Restricted air passages Inspect and replace transfer tubes or the check valve, (see “To replace

or clean check valve” in the maintenance section).

Excessive belt wear Pulley out of alignment Realign pulley with compressor flywheel.

Improper belt tension Readjust.
Pulley wobbles Replace the pulley and check for a damaged crankshaft or flywheel.

Compressor won’t start
in cold temperatures

Too much back pressure in tank Open petcock when starting motor.
40W oil in crankcase Use synthetic, non-detergent air compressor oil.
Compressor too cold Move compressor to a warmer location.

Air leaking through
bleeder valve after
compressor shuts off

Dirty or defective check valve. Replace or clean the check valve (see “To replace or clean check

valve” in the maintenance section).