National Flooring Equipment 3390 User manual

#3390 SHOTBLAST
INSTRUCTION MANUAL
Read Manual Before Operating Machine
9250 XYLON AVENUE NORTH • MINNEAPOLIS, MN 55445 • U.S.A.
800-245-0267 • 763-535-8206 • FAX [phone] • FAX [phone]
WEB SITE: www.nationalequipment.com • E-MAIL: [email protected]
National
Flooring Equipment, Inc.

Page 2
TABLE OF CONTENTS
Table of Contents ........................................................................................................2
Rules for Safe Operation..........................................................................................3-7
A. Characteristics of a Defensive Driver ..................................................................5
B. SAFETY SITE ASSESSMENT ............................................................................5
C. Grounding ............................................................................................................6
D. Extension Cords ..................................................................................................7
Safety Instructions ......................................................................................................8
General Information ....................................................................................................9
Features/Specifications ............................................................................................10
General Operation ................................................................................................11-15
Troubleshooting....................................................................................................16-17
Maintenance Log ......................................................................................................18
Guarantee..................................................................................................................19
Return Sheet ............................................................................................................20

Page 3
RULES FOR SAFE OPERATION
READ AND SAVE ALL INSTRUCTIONS FOR FUTURE USE. Before use, be sure everyone
operating this equipment reads and understands this manual as well as any labels packaged with or
attached to the machine. Extra copies of the manual are available upon request.
1. KNOW YOUR EQUIPMENT: Read this manual and view instruction video carefully to learn
equipment applications and limitations as well as potential hazards associated with this type of
equipment.
2. GROUND YOUR TOOL: See Grounding page 6.
3. AVOID DANGEROUS ENVIRONMENTS: Do not use in rain, damp or wet locations, or in the
presence of explosive atmospheres (gaseous fumes, dust or flammable materials). Remove materials
or debris that may be ignited by sparks.
4. KEEP WORK AREA CLEAN AND WELL LIT: Cluttered, dark work areas invite accidents.
5. DO NOT USE ON STEPS
6. DRESS PROPERLY: Do not wear loose clothing. These may be caught in moving parts. When
working outdoors, wear rubber gloves and insulated non-skid footwear. Keep hands and gloves away
from moving parts.
7. USE SAFETY EQUIPMENT: Everyone in the work area should wear safety goggles or glasses
complying with current safety standards. Wear hearing protection during extended use and a dust
mask for dusty operations. Hard hats, face shields, safety shoes, etc. should be worn when specified
or necessary.
8. KEEP BYSTANDERS AWAY: Children and bystanders should be kept at a safe distance from the
work area to avoid distracting the operator and contacting the tool or extension cord. Operator should
be aware of who is around them and their proximity.
9. PROTECT OTHERS IN THE WORK AREA: Provide barriers or shields as needed to protect others
from debris and machine operation.
10. USE PROPER ACCESSORIES: Using accessories that are not recommended may be hazardous.
Be sure accessories are properly installed and maintained. Do not delete a guard or other safety
device when installing an accessory or attachment.
11. CHECK FOR DAMAGED PARTS: Inspect guards and other parts before use. Check for
misalignment, binding of moving parts, improper mounting, broken parts and any other conditions that
may affect operation. If abnormal noise or vibration occurs, turn the tool off immediately and have the
problem corrected before further use. Do not use damaged equipment. Tag damaged tools “DO NOT
USE” until repaired. A guard or other damaged parts should be properly repaired or replaced. For all
repairs, insist on only identical National replacement parts.
12. REMOVE ALL ADJUSTING KEYS AND WRENCHES: Make a habit of checking that the adjusting
keys, wrenches, etc. are removed from the tool before turning it on.
13. GUARD AGAINST ELECTRIC SHOCK: Prevent body contact with grounded surfaces such as pipes,
radiators, ranges and refrigerators. When scoring or making cuts, always check the work area for
hidden wires or pipes. Hold machine by insulated nonmetal grasping surfaces. Use a Ground Fault
Circuit Interrupter (GFCI) to reduce shock hazards.
14. AVOID ACCIDENTAL STARTING: Be sure equipment is turned off before plugging it in. Do not use
if the power switch does not turn the machine on and off.

Page 4
RULES FOR SAFE OPERATION
15. DO NOT FORCE EQUIPMENT: Equipment will perform best at the rate for which it was designed.
Excessive force only causes operator fatigue, increased wear and reduced control.
16. KEEP HANDS AWAY FROM ALL MOVING PARTS.
17. WEAR GLOVES WHEN CHANGING ACCESSORIES.
18. DO NOT ABUSE CORD: Never unplug by yanking the cord from the outlet. Pull plug rather than cord
to reduce the risk of damage. Keep the cord away from heat, oil, sharp objects, cutting edges and
moving parts.
19. DO NOT OVERREACH. MAINTAIN CONTROL: Keep proper footing and balance at all times.
Maintain a firm grip.
20. STAY ALERT: Watch what you are doing, and use common sense. Do not use when you are tired,
distracted or under the influence of drugs, alcohol or any medication causing decreased control.
21. STARTING MACHINE: On/off switch must be in off position before connecting to power source.
22. UNPLUG EQUIPMENT: When it is not in use, unplug tool before changing blades, accessories or
performing recommended maintenance or when not in use.
23. MAINTAIN EQUIPMENT CAREFULLY: Keep handles dry, clean and free from oil and grease. Keep
cutting edges sharp and clean. Follow instructions for lubricating and changing accessories.
Periodically inspect tool cords and extension cords for damage. Have damaged parts repaired
or replaced.
24. STORE IDLE EQUIPMENT: When not in use, store in a dry, secured place. Keep away
from children.
25. MAINTAIN LABELS AND NAMEPLATES: These carry important information. If unreadable or
missing, contact National for a free replacement.
26. MACHINE IS HEAVY, DO NOT DROP: Counter weights are heavy. Take caution when removing
or reassembling. Take caution when moving or transporting.
WARNING: Exposure to dust may cause respiratory ailments. Use approved NIOSH or OSHA
respirators, safety glasses or face shields, gloves and protective clothing. Provide adequate ventilation
to eliminate dust, or to maintain dust level below the Threshold Limit Value for nuisance dust as
classified by OSHA.

Page 5
RULES FOR SAFE OPERATION
CHARACTERISTICS OF A DEFENSIVE OPERATOR
• Education
• Alert
• Skills
• Judgment
• Common Sense
• Recognizes the Hazards
• Understands the Defense
• Acts Correctly
A GOOD OPERATOR IS A “DEFENSIVE” OPERATOR
QUALITIES
Education: Learns about the machine and the environment.
Alert: Stays alert at all timesnever lets guard down.
Skills: Only performs duties he/she are qualified to do. Always tries to improve.
Judgment: Plays it safe. Doesn’t take chances.
Common Sense: Does the right thing without having to be told. Applies knowledge.
Recognizes the Hazards: Maintains alertness. Anticipates danger.
Understands the Defense: Knows that safety isn’t an accidentit’s a thinking person’s choice.
Acts Correctly: Does not cave in to pure pressure. Performs correctly when supervised or not.
SAFETY SITE ASSESSMENT
Before starting blasting operations as site assessment should be performed. During the site assessment
verify the following:
1. Work area is clean, dry, free of debris, and machine will clear all obstructions. NEVER BLAST AWET
FLOOR AND NEVER ALLOW PERSONNEL, ELECTRICAL CORDS, OR CONNECTIONS TO COME INTO CONTACT WITH
MOISTURE. NEVER BLAST OVER NUTS, BOLTS, SCREWS, NAILS OR OTHER DEBRIS AS THIS MAY RESULT IN SIGNIFICANT
DAMAGE TO THE MACHINE AND SERIOUS INJURY TO THE OPERATOR.
2. Operator any any other personnel in the work area are wearing safety glasses with side shield, dust
masks, ear plugs, hard hats, steel toed work boots, long sleeved shirts and gloves.
3. All glass and equipment are protected from steel shot. This can be done by loosely hanging a sheet of
visquene or other protective material in front of the window or equipment in a curtain like fashion. THE
IMPORTANCE OF PROTECTING EQUIPMENT AND MACHINERY FROM STEEL SHOT CANNOT BE OVER EMPHASIZED.
4. Plug or cover all floor drains to prevent steel shot from falling into the drains.
5. Do not allow pedestrians or unprotected personnel into the work area. In the event pedestrians or
other unprotected personnel enter the work area, cease blasting operations.

Page 6
RULES FOR SAFE OPERATION
WARNING: Improperly connecting the grounding wire can result in the risk of electric shock.
Check with a qualified electrician if you are in doubt as to whether the outlet is properly grounded. Do
not modify the plug provided with the tool. Never remove the grounding prong from the plug. Do not
use the tool if the cord or plug is damaged. If the plug will not fit the outlet, have a proper outlet
installed by a qualified electrician.
GROUNDED TOOLS: TOOLS WITH THREE PRONG PLUGS
Tools marked “Grounding Required” have a three wire cord and three prong grounding plug. The plug
must be connected to a properly grounded outlet (See Figure A). If the tool should electrically malfunction
or break down, grounding provides a low resistance path to carry electricity away from the user, reducing
the risk of electric shock.
The grounding prong in the plug is connected through the green wire inside the cord to the grounding
system in the tool. The green wire in the cord must be the only wire connected to the tool's grounding
system and must never be attached to an electrically “live” terminal.
Your tool must be plugged into an appropriate outlet, properly installed and grounded in accordance with
all codes and ordinances. The plug and outlet should look like those in Figure A.
Figure A
2
1
3
GROUNDING
1. Cover of grounded outlet box
2. Outlet ground
3. Grounding prong
WARNING: Electrical cords can be hazardous. Misuse can result in fire or death by electrical
shock. Read carefully and follow all directions.

Page 7
RULES FOR SAFE OPERATION
EXTENSION CORDS
Grounded tools require a three wire extension cord. Double insulated tools can use either a two or three
wire extension cord. As the distance from the supply outlet increases, you must use a heavier gauge
extension cord. Using extension cords with inadequately sized wire causes a serious drop in voltage,
resulting in loss of power and possible tool damage.
The smaller the gauge number of the wire, the greater the capacity of the cord. For example, a 14 gauge
cord can carry a higher current than a 16 gauge cord. When using more than one extension cord to make
up the total length, be sure each cord contains at least the minimum wire size required. If you are using
one extension cord for more than one tool, add the nameplate amperes and use the sum to determine the
required minimum wire size.
GUIDELINES FOR USING EXTENSION CORDS
• If you are using an extension cord outdoors, make sure it is marked with the suffix “W-A” (“W” in
Canada) to indicate that it is acceptable for outdoor use.
• Be sure your extension cord is properly wired and in good electrical condition. Always replace a
damaged extension cord or have it repaired by a qualified person before using it.
• Protect your extension cords from sharp objects, excessive heat and damp or wet areas.
• Keep away from water. Do not use if wet.
• Inspect thoroughly before each use. DO NOT USE IF DAMAGED.
• Make sure equipment is OFF before connecting cord outlet.
• FULLY INSERT plug into outlet.
• Do not remove, bend or modify any metal prongs or pins of cord.
• Do not use excessive force to make connections.
• Do not connect a three prong plug to a two-hole cord.
• Avoid overheating. Uncoil cord and do not cover it with any material.
• Do not walk on cord.
• Do not drive, drag or place objects over cord.
READ AND SAVE ALL INSTRUCTIONS FOR FUTURE REFERENCE.
WARNING: Electrical cords can be hazardous. Misuse can result in fire or death by electrical
shock. Read carefully and follow all directions.

Page 8
SAFETY INSTRUCTIONS
• Only qualified, trained personnel should operate this unit.
• Loose or damaged parts should be replaced immediately. Failure to do so could cause equipment
damage or serious injury.
• Switches and levers should be inspected. Do not use if defective.
• Power control box, motor and switches should be completely enclosed at all times with no
exposed wiring.
• Disconnect power from unit before servicing. Failure to do so can cause electrical shock.
• Only use National components. Failure to do so could cause damage or serious injury.
• Always be aware of support personnel and their proximity when in operation. Block off
work area.
• Support personnel should never stand next to machine, in front of or behind machine while machine is
running. Failure to do so could cause serious bodily injury or death.
• Manual should be kept with machine in supplied holder for access by operator at all times.
• Operating personnel should practice safety at all times and wear protective gear (breathing apparatus,
gloves, goggles, safety vests, ear plugs, steel-toe shoes, etc.).
• Never defeat switches or guards.
WARNING: Know and understand before operation. Failure to do so could cause damage to
equipment or bodily injury.
Read and understand operators instruction manual and before operating this
equipment.
WARNING: Failure to follow any of the above instructions could cause damage to machine,
damage to property or serious bodily injury or death.
WARNING: SILICA DUST WARNING
Grinding/cutting/drilling of masonry, concrete, metal and other materials can
generate dust, mists and fumes containing chemicals known to cause serious fatal
injury or illness, such as respiratory disease, cancer, birth defects or other
reproductive harm. If you are familiar with the risks associated with the particular
material being cut, review the material safety data sheet and/or consult you
employer, the material manufacturer/supplier, governmental agencies such as
OSHA and NIOSH and other sources of hazardous materials. California and some other other
authorities, for instance, have published lists of substances known to cause cancer, reproductive
toxicity, or other harmful effects. Control dust, mist and fumes at the source where possible. In this
regard use good work practices and follow the recommendations of the manufacturer/supplier,
OSHA/NIOSH, and occupational and trade associations. When the hazards from inhalation of dust,
mists and fumes cannot be eliminated, the operator and any bystanders should always wear a
respirator approved by OSHA/MSHA for the material being cut.

Page 9
UNCRATING YOUR EQUIPMENT
When you uncrate your equipment, make certain that the machine has not been damaged and that all
fasteners and guards are properly tightened.
Your machine may not have been shipped assembled with drums and other accessories. Assembly may
be required.
GENERAL INFORMATION
To ensure product safety and reliability, and to maintain your warranty, always use genuine
NATIONAL replacement cutters and parts when making repairs to equipment.
STORAGE
Prevent rust during storage. Store machine upright in a cool, dry, well ventilated area.
MAINTENANCE CHECKS
According to the conditions and frequency of use, scarifiers have to be checked for safe operation at
least once a year by skilled technicians, such as those found at the manufacturer’s service depots, and
have to be repaired if necessary.
ORDERING
When ordering please specify the model and serial number of the machine. In addition, give a part
number, description, and quantity as listed on your parts list.
If you have any questions about the operation of your machine or would like to order replacement parts,
contact National at: 800-245-0267 or 763-535-8206

Page 10
FEATURES/SPECIFICATIONS
DUST COLLECTOR RUWAC LITTLE RED
Dimensions:(L x W x H) 32" x 20" x 35"
Weight: 92 lbs.
9 gallon dust pan
2" Inlet
13 sq. ft. MicroClean filter
97 H20
Production Capacity: 200 CFM
Voltage: 110 Volt
The #3390 is an affordable 110v blast cleaning system designed for small to medium jobs as well as
being a complimentary unit on larger jobs for doing edges and hard to reach areas. The #3390 has a 9"
blast pattern and has the capability of 1/8" depth removal in one pass. The unit is portable, light weight,
and cleans/profiles in one easy step. Shot sizes range from S-170 to S-390, which can be used in a wide
range of applications including small floor areas, tight spaces, balconies, garage floors, basements and
pool decks. Wear parts are interchangeable with National®parts.
The primary components of the #3390 are as follows:
• Shot Hopper
• Shot Lever
• Shot Valve
• Feed Spout
• Blast Wheel
• Control Cage
• 110 Volt Right Angle Motor
• Blast Housing
• Duct Hose
• Dust Collector
• Dust Bin
MODEL NUMBER #3390
Dimensions w/o Handle:
(L x W x H) 24.5" x 12.5" x 20"
Dimensions w/ Handle in
position:
(L x W x H)
42.5" x 12.5" x 39"
Weight: 121 lbs.
Production Capacity: 250 sq. ft./hr.
Seals: Magnetic
Cleaning Path: 8"
Distance to Edge: 2.5"
Travel Speed: Manual
Blast Motor: 3.35 h.p.
Voltage: 120 V
Power Source: 110 VAC / power cord included

Page 11
GENERAL OPERATION
PRIMARY COMPONENTS/HOW #3390 SHOTBLAST WORKS
The shot hopper is the area of the machine where steel shot is initially loaded into the machine. A shot
lever is attached to the handle of the machine and when the lever is squeezed a cable connected to the
lever opens the shot valve. As the shot valve is opened, steel shot fall through the shot valve and passes
through the feed spout into the blast wheel. The blast wheel sits in a control cage. A 110 volt right angle
motor spins the blast wheel at a very high rate of speed. As the steel shot falls into the spinning blast
wheel it is thrown by the blast wheel through an opening in the control cage and down on to the floor
being cleaned. Due to high rate of speed at which the steel shot is traveling, the steel shot fractures the
concrete surface producing concrete dust. The shot rebounds, or bounces off of the floor and through a
combination of the the rebound effect and the use of a vacuum the steel shot and the concrete dust travel
through the blast housing. The steel shot is heavier than the concrete dust. Due to the difference in the
weight of the steel shot compared to the weight of the concrete dust the steel shot, through gravitation
force, is deposited back into the shot hopper and is recycled through the machine.
After traveling through the blast housing, the concrete dust is sucked into a duct hose which travels from
the blast housing to the dust collector. After traveling through the duct hose the concrete dust deposited
into the dust collector’s dust bin.
SAFETY START UP PROCEDURE
After performing the safety site assessment procedures bring the #3390 and dust collector to the work
area and perform the following procedures:
1. Inspect all electrical cords on the #3390 and dust collector for damage, tears or other signs of wear. If
electric cords are damaged do not attempt to perform blasting operations until cords have been repaired
or replaced.
2. Inspect the #3390 blast wheel, control cage, feed spouts, liners, seals, shot hopper, magnets and
other parts for wear. Replace worn parts where necessary.
3. Inspect the duct hose leading from the #3390 to the dust collector. Make sure hose is free of debris,
hose is not cracked and holes do not exist. If necessary replace hose.
4. Inspect the dust collector. Verify that dust bin is empty, filters are clean and clear of debris, motors
and fans are in working order. NOTE: THE DUST BIN SHOULD BE EMPTIED AT THE END OF EACH JOB.
5. Locate the #3390 adjacent to the dust collector and blast in straight lines moving away from the dust
collector. Blasting in straight lines will produce the most uniform results. Working away from the dust
collector will help prevent cords and hoses from becoming an obstruction. NEVER RUN OVER AN ELECTRICAL
CORD OR AHOSE WITH THE #3390. RUNNING OVER AND ELECTRICAL CORD WITH THE #3390 CAN RESULT IN
SERIOUS INJURY TO THE OPERATOR AND DAMAGE EQUIPMENT.

Page 12
SAFE OPERATION
SAFETY SHUT DOWN PROCEDURE
When shutting down the #3390 perform the following safety procedures:
1. Close shot valve by releasing the shot lever.
2. Turn off breakers to the #3390 and dust collector
3. Turn switch on #3390 and dust collector to the OFF position.
4. Empty dust from the dust bin. WHEN REMOVING DUST FROM DUST BIN ALWAYS WEAR APARTICLE MASK.
CONCRETE DUST MAY CONTAIN PARTICLES WHICH ARE HAZARDOUS TO YOUR HEALTH - THESE PARTICLES SHOULD NOT
BE INHALED.
5. Empty all shot from the shot hopper on the #3390. Shot should never be left in #3390 after work is
performed. Never move or transport #3390 with shot in the shot hopper.
6. After completing work, clean all stray shot from work area. Shot can be cleaned with a magnetic
broom, a shop vac, or compressed air. Never leave stray shot in work area as shot is a slip and fall
hazard. Stepping and falling on steel shot can result in serious injury.
A well-maintained machine is a productive machine. If not properly maintained, it could be unsafe
and could break down. A scheduled maintenance program should insure a long system life and a safe
work environment.
MAINTENANCE
1.Always wear eye protection.
2. Keep flammable and fragile objects away from this tool.
3. Always check nuts and bolts to make sure they are tight.
4. Always use the tool with proper voltage specified in the machine’s name plate.
5. Always keep guards in place.
6. Do not operate around water or wet conditions without use of GFI on cord.
7. Use properly grounded cord and receptacle.
8. Unplug from power before servicing.
9. Use 12 gauge or heavier wire cord, not exceeding 50 feet in length.
10. Do not force machine.
11. Do not alter machine.
12. Pressure valve has been factory set and should NOT be tampered with.
13. Keep wheels free from debris.

Page 13
GENERAL OPERATION
OPERATING MACHINE
1. Verify that competent personnel have read and understand the safety information in this manual and
are following all safety instructions and programs required by their company and the worksite. Verify
that the #3390 in on a level, clean, debris-free and dry surface.
2. Connect hose from dust collector to #3390. Verify clamps are secure. Verify that the #3390 is on a
level, clean, debris-free and dry surface.
3. Verify dust bin in dust collector is empty and hose is free of debris.
4. Verify the switch on the control panel on the #3390 is set to the OFF position.
5. Verify the switch on the control panel on the dust collector is set to the OFF position.
6. Insert plug from #3390 into 110 volt electrical outlet after confirming proper voltage with a voltmeter.
7. Insert plug from the dust collector into 110 volt electrical outlet. Use an outlet which is operated by a
separate circuit breaker from the outlet being used to power the #3390. Confirm voltage of electrical
outlet with a voltmeter.
8. Any hardwiring or circuit breaker changes should be performed by a licensed electrician.
9. Before loading shot into machine turn the switch on the #3390 and the dust collector to the ON
position for two minutes to verify circuit breaker will not trip.
10. Disconnect hose from the #3390 to verify dust collector has proper suction.
11. After verifying proper suction reconnect hose to the #3390.
12. Check seals on #3390 to verify seals are set at the proper height. The seals should be rubbing the
surface of the concrete or steel.
13. Place a handful of steel shot in front of the #3390.
14. Push #3390 over the handful of steel shot. This will attach the steel shot to the magnetic seals an
prevent shot from escaping from #3390.
15. Pour steel shot into #3390 shot hopper to the bottom of the screen.
16. Turn switch on #3390 to the ON position, squeeze handle to open shot valve and push #3390. Verify
blast pattern is uniform. If blast pattern is not uniform, release handle to close shot valve and turn
switch on #3390 to the OFF position and go to step 17 below.
17. Adjust the control cage.
18. Turn switch on #3390 to ON position, squeeze handle to open shot valve, push #3390, and verify
blast pattern is uniform.
19. Once blast pattern is uniform start shotblasting.

Page 14
PROCEDURE
SETTING THE BLAST PATTERN
Setting the proper blast pattern is determined by trial and error. The importance of selecting the proper
blast pattern can not be overstated. An improper or unevenly distributed blast pattern results in
excessive blasting on either the right or left side of the machine and leaves shadows or “track” lines in the
blast pattern.
When setting the blast pattern perform the following steps:
Verify the blast wheel is rotating in the direction shown on the blast housing. Place a sheet of steel
approximately 1/4" thick under the machine and blast with the shot valve fully open for approximately on
minute. Do not move the machine. After blasting for one minute shut down the machine and inspect the
blast pattern. The “hot spot” should be in the center of the width blasted. The “hot spot” can be altered
by rotating the control cage. Rotating the control cage in a counter-clockwise direction will move the “hot
spot” to the right while rotating the control cage in a clockwise direction will move the “hot spot” to the left.
If you visualize a clock, the opening of the control cage should be set at approximately 10:30 and 8:30 on
the clock. The size of the steel shot used will impact where the “hot spot” appears in the blast pattern.
The operator will need to adjust the control cage based upon the size of steel shot utilized.
WEAR PARTS
The #3390 contains parts which are continually exposed to steel shot moving at high rates of speed.
Exposure to steel shot traveling at high rates of speed and concrete dust cause these parts to deteriorate
thus they are known as wear parts. As a result, the operator or maintenance personnel should inspect
the #3390 wear parts prior to operation and change the parts as necessary. Wear parts and inspection
times, other than inspection prior to use, on the #3390 are listed as follows:
PART WHEN TO INSPECT EVIDENCE OF WEAR
Shot Hopper 30 Hrs Warping or Thin Spots
Feed Spout 50 Hrs Thin Spots
Blast Wheel 10 Hrs Blades Deteriorated > 40%
Control Cage 10 Hrs Deteriorated Edges
Blast Wheel Hub 10 Hrs Missing Pins/Deterioration
Liners 10 Hrs Warping/Holes/Deterioration
Blast Housing 50 Hrs Thin Section or other Deterioration
Parts of the #3390 which should also be inspected regularly but are not exposed to steel shot are the
control panel, motor, electric cords, dust collector hose, filters and motors. If any of these components
show signs of wear they should be repaired so that they are in the same working condition as when they
were new. If they cannot be repaired they should be replaced immediately.

PROCEDURE
BLAST WHEEL REPLACEMENT
When the blades on the blast wheel are deteriorated by 50% or more the blast wheel should be replaced.
To replace the blast wheel, perform the following steps:
• Verify control switch in the OFF position
• Verify power cord in NOT plugged into an electrical outlet
• Verify shot valve is closed
• Loosen nuts and clamps that secure feed spout and control cage
• Remove feed spout
• Remove control cage
• Mark plate with ink pen where control cage openings appear to aid in realignment
• Remove four sets of nuts and washers securing control cage assembly to housing
• Remove control cage assembly
• Remove arbor nut and blast wheel
• Check wheel hub for wear & replace as necessary
• Install new blast wheel and arbor nut
• Attach the control cage assembly previously removed
• Insert new control cage provided with blast wheel kit. Spin blast wheel by hand to verify blast wheel
and control cage do not come into contact. Openings of control cage should be set at approximately
10:30 and 8:30.
• Reattach feed spout
• Verify all nuts are tight and secure
• Briefly activate grinder motor to verify good balance & proper clearance
NOTE: Only blast wheels manufactured by National should be used in the #3390. Other blast
wheels have not been tested by National and could result in damage to the equipment or injury to
the operator.
Page 15

Page 16
TROUBLESHOOTING
Problem Possible Cause Remedy
1. Breaker is tripping when
#3390 and dust collector are
turned to the ON position
a. #3390 and dust collector
should be powered by separate
breakers.
a. Find electric outlets with
separate breaker switches and use
accordingly.
b. Check circuit breaker sizes
2. #3390 is vibrating excessively a. Excessive vibration is usually
caused by the blast wheel being
out of balance due to it being
worn or blades being broken or
chipped.
a. Check blast wheel immediately.
b. Install new blast wheel kit.
Failure to install new wheel kit in
this instance can lead to serious
damage to machine.
3. #3390 is creating excessive
noise
a. This problem is most likely
caused by an improper
alignment of the blast wheel
and control cage.
a. Check alignment of blast wheel
and control cage immediately and
verify there is adequate clearance
between the blast wheel and the
control cage.
4. #3390 is creating excessive
wear on liners and blast housing.
a. Adjust control cage so that “hot
spot” is centered in work area
rather than on liners or housing.
5. #3390 is dropping excessive
amount of steel shot.
a.Verify “hot spot” is centered
properly and adjust control cage as
necessary.
b. Verify seals do not have
excessive wear, feed spout is
aligned properly, and shot valve is
closing when shot lever is
released.
c. Verify dust collector has
adequate suction.
6. #3390 blasting performance
has diminished.
a. Verify there is an adequate
amount of steel shot in the shot
hopper and shot is free of concrete
dust or other contaminates.
b.Verify there are no obstructions
in the shot valve or feed spout and
the feed spout is properly aligned.
c. Verify shot valve is opening
properly.
d. Verify blast wheel and control
cage are not excessively worn.
e. Verify dust collector has
adequate suction.
CONTINUED ON NEXT PAGE

Page 17
TROUBLESHOOTING
Problem Possible Cause Remedy
7. 3390 is difficult to push or gets
stuck in areas.
a. Verify the seals are positioned
properly and are not to close to the
floor.
b. Raise height of seals.
8. The steel shot in the shot
hopper contains an excessive
amount of concrete dust.
a. Poor vacuum suction
b.
a. Verify that vacuum has good
suction.
b. If this does not resolve problem,
increase the travel speed of the
#3390 to reduce amount of
concrete being removed.
c. If “b” does not produce an
adequate profile make additional
passes over the floor surface.
9. #3390 or dust collector is
emitting concrete dust.
a. Verify there are no holes in the
duct hose leading from the #3390
to the dust collector.
b. Verify filters in the dust collector
are properly installed and are
clean. If necessary, replace filters
in dust collector.
10. Steel shot is being sucked
into dust bin.
a. Dust collector is producing
too much suction for the size of
shot being used.
a. Restrict air flow on dust
collector.

Page 18
SAFE OPERATION
MAINTENANCE LOG
WARRANTY CLAIMS
The manufacturer reserves the right to change or improve the machine design without assuming any
obligation to update any products previously manufactured before this manual. It is the customer’s
responsibility to complete the warranty card and mail it to the seller within 10 days from date of purchase.
If a failure occurs during the warranty period, the customer must contact the seller to determine the
appropriate action. Any an all transportation charges are to be borne by the purchaser.

Page 19
112608
National Flooring Equipment, Inc. (National) warrants to the first consumer/purchaser that this National
brand product (the #3390 Shotblast), when shipped in its original container, will be free from defective
workmanship and materials and agrees that it will, at its option, either repair the defect or replace the
defective product or part thereof at no charge to the purchaser for parts or labor for the period(s) set forth
below.
This warranty does not apply to any appearance items of the product, to the additional excluded items set
forth below, or to any product, the exterior of which has been damaged or defaced, which has been
subjected to misuse, abnormal service or handling, or which has been altered or modified in design or
construction.
In order to enforce the rights under this limited warranty, the purchaser should follow the steps set forth
below and provide proof of purchase to National.
The limited warranty described herein is in addition to whatever implied warranties may be granted to
purchasers by law. ALL IMPLIED WARRANTIES INCLUDING THE WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR USE ARE LIMITED TO THE PERIODS FROM THE DATE OF
PURCHASE AS SET FORTH BELOW. Some states do not allow time limitations on an implied warranty,
so the above limitation may not apply to you.
Neither the sales person of the seller, nor any other person, is authorized to make any other warranties
other than those described herein, or to extend the duration of any warranties beyond the time period
described herein on behalf of National.
The warranties described herein shall be the sole and exclusive warranties granted by National and shall
be the sole and exclusive remedy available to the purchaser. Correction of defects in the manner and for
the period of time described herein, shall constitute complete fulfillment of all liabilities and
responsibilities of National to the purchaser with respect to the product and shall constitute full
satisfaction of all claims, whether based on contract, negligence, strict liability or otherwise. In no event
shall National be liable, or in any way responsible for any damage or defects in the product which were
caused by repairs or attempted repairs performed by anyone other than National. Nor shall National be
liable, or in any way responsible, for any incidental or consequential, economics or property damage.
Some states do not allow the exclusion of incidental or consequential damages, so the above exclusion
may not apply to you.
THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS. YOU MAY ALSO HAVE OTHER RIGHTS
WHICH VARY FROM STATE TO STATE.
WARRANTY PERIOD
The #3390 Shotblast is guaranteed to be free of manufacturer defective workmanship and in quality of
materials for a period 90 days.
Items excluded from warranty coverage, unless found and reported defective immediately upon removal
from the original shipping container and before being used by the original purchaser.
A freight damage claim must be filed with the carrier by the purchaser, the shipper cannot file the freight
claim.
To obtain service contact National Flooring Equipment, Inc. toll free at 800-245-0267 for a repair
authorization number. COD freight returns will not be accepted. Freight collect shipments will not be
accepted. Warranty repairs must be accompanied by date of purchase receipt and a return/repair
authorization number.
GUARANTEE

Page 20
RETURN SHEET
Company Name
Contact Name
Telephone Number
Approximate Usage (hours)
Problems Encountered
Check One: Repair
Do you wish to be contacted before repairing  Yes  No
Return
Contact National if a loaner is needed
Return Authorization Number Date
Customer Number
Purchased From
required, contact National
INTERNAL USE ONLY
Date Received
Unit Serial Number
Subject To Warranty
if known
if not directly from National