KOBE RAX21 SQB-X Series Troubleshooting guide

KOBE Range Hoods
Brillia Series
RAX21 SQB-X Series
Under Cabinet Model:
RAX2130SQB-1 (30”) / RAX2130SQB-2 (30”)
RAX2136SQB-1 (30”) / RAX2136SQB-2 (36”)
RAX2142SQB-1 (42”) / RAX2142SQB-2 (42”)
Wall Mount Model:
RAX2130SQB-WM-1 (30”) / RAX2130SQB-WM-2 (30”)
RAX2136SQB-WM-1 (36”) / RAX2136SQB-WM-2 (36”)
RAX2142SQB-WM-1 (42”) / RAX2142SQB-WM-2 (42”)
INSTALLATION INSTRUCTIONS
AND OPERATION MANUAL

IMPORTANT
READ THIS FIRST
READ BEFORE INSTALLATION
1. Carefully check all contents of package(s).
2. Thoroughly inspect the unit for any shipping damages, cosmetic
damages or defects.
3. Have a certified contractor/electrician test the unit before installation.
IF THERE IS ANY PROBLEMS:
1. DO NOT INSTALL THE UNIT AND KEEP ALL ORIGINAL
PACKAGING MATERIALS.
2. Have your invoice as proof of purchase and product serial number
ready.
3. Contact your merchant for product replacement due to shipping
damages, cosmetic damages or defects.
4. For all other issues, email [e-mail]
NO RETURN, NO REFUND, NO EXCHANGE IF:
1.PRODUCT HAS BEEN INSTALLED
2.KNOCK-OUT HOLES HAVE BEEN PUNCTURED
3.MISSING ORIGINAL PACKAGING MATERIAL
AND/OR PARTS

[ENGLISH]
- READ AND SAVE THESE INSTRUCTIONS -
CONTENTS
IMPORTANT SAFETY INSTRUCTIONS ........................................................................1
COMPONENTS OF PACKAGE ......................................................................................3
INSTALLATION...............................................................................................................5
OPERATING INSTRUCTIONS .....................................................................................10
MAINTENANCE............................................................................................................11
SPECIFICATIONS ........................................................................................................12
MEASUREMENTS & DIAGRAMS.................................................................................13
PARTS LIST..................................................................................................................14
CIRCUIT DIAGRAM......................................................................................................16
TROUBLE SHOOTING.................................................................................................17
WARRANTY..................................................................................................................18
WARRANTY INFORMATION FORM............................................................................20
- READ ALL INSTRUCTIONS CAREFULLY BEFORE STARTING -
ALL WIRING MUST BE DONE BY A PROFESSIONAL AND
IN ACCORDANCE WITH NATIONAL AND LOCAL ELECTRICAL CODES
Control Number: 5011098

1
IMPORTANT SAFETY INSTRUCTIONS
- PLEASE READ THIS SECTION CAREFULLY BEFORE INSTALLATION -
WARNING: TO REDUCE THE RISK OF FIRE, ELECTRIC SHOCK OR PERSONAL INJURY,
OBSERVE THE FOLLOWING:
1. Installation and electrical wiring must be done by qualified professionals and in accordance with
all applicable codes and standards, including fire-rated construction.
2. When cutting or drilling into wall or ceiling, be careful not to damage electrical wiring or other
hidden utilities.
3. Ducted fans must be vented to the outside.
a. Before servicing or cleaning unit, open the light panel and SWITCH POWER OFF AT
SERVICE PANEL.
b. Clean all grease laden surfaces frequently. To reduce the risk of fire and to disperse air
properly, make sure to vent air outside. DO NOT vent exhaust air into wall spaces, attics,
crawl spaces or garages.
NOTE
-
This warrant is void without an authorized agent’s receipt or if unit is
damaged due to misuse, poor installation, improper use, mistreatment,
negligence or any other circumstances beyond the control of KOBE
authorized agents. Any repair carried out without the supervision of KOBE
authorized agents automatically void the warranty.
-
KOBE will not be held responsible for any damages to personal property
or real estate or any bodily injuries whether caused directly or indirectly
by the range hood.
WARNING: TO REDUCE THE RISK OF PERSONAL INJURY IN THE EVENT OF A RANGE
TOP GREASE FIRE:
1. Keep all fan, baffle/spacer/filter/oil tunnel/oil container and grease-laden surfaces clean. Grease
should not be allowed to accumulate on fan, baffle/spacer/filter/oil tunnel/oil container.
2. Always turn hood ON when cooking.
3. Use high setting on cooking range ONLY when necessary.
4. Do not leave cooking range unattended when cooking.
5. Always use cookware and utensils appropriate for the type and amount of food prepared.
6. Use this unit only in the manner intended by the manufacturer.
7. Before servicing, switch power off at service panel and lock service panel (if possible) to prevent
power from switching on accidentally.
8. Clean ventilating fan frequently.

2
What to Do in the Event of a Range Top Grease Fire
1. SMOTHER FLAMES with a tight fitting lid, cookie sheet, or metal tray, and then turn off the burner.
KEEP FLAMMABLE OR COMBUSTIBLE MATERIAL AWAY FROM FLAMES. If the flames do
not go out immediately, EVACUATE THE AREA AND CALL THE FIRE DEPARTMENT or 911.
2. NEVER PICK UP A BURNING PAN –You May Get Burned.
3. DO NOT USE WATER, including wet dishcloths or towels –a steam blast will result.
4. Use an extinguisher ONLY if:
a. You have a Class A, B, C extinguish and know how to operate it.
b. The fire is small and contained in the area where it started.
c. The fire department has been called.
d. You can fight the fire with your back to an exit.
What TO Do If You Smell Gas
1. Extinguish any open flame.
2. Do not try to turn on the lights or any type of appliance.
3. Open all doors and windows to disperse the gas. If you still smell gas, call the Gas Company and
Fire Department right away.
CAUTION
1. For general ventilation use only. Do not use to exhaust hazardous or explosive materials and
vapors.
2. To reduce the risk of fire, use only metal ductwork. Sufficient air is needed for proper combustion
and exhausting of gases through the flue (chimney) to prevent back drafting.
3. Follow the heating equipment manufacturer’s guideline and safety standards such as those
published by the National Fire Protection Association (NFPA), and the American Society for
Heating, Refrigeration and Air Conditioning Engineers (ASHRAE), and code authorities.
4. Activating any switch may cause ignition or an explosion.
5. Due to the size and weight of this hood, installation by 2 persons is recommended.
ELECTRICAL SHOCH HAZARD –Can result in serious injury or death.
Disconnected appliance from electric power before servicing. If
equipped, the fluorescent light bulb contains small amount of mercury,
which must be recycled or disposed of according to Local, State, and
Federal Codes.

3
COMPONENTS OF PACKAGE
(Must keep all materials for returns or refunds)
For Under Cabinet Application
Model No.: RAX2130SQB-1 (30”) / RAX2130SQB-2 (30”)
RAX2136SQB-1 (36”) / RAX2136SQB-2 (36”)
RAX2142SQB-1 (42”) / RAX2142SQB-2 (42”)
Range Hood Box
{A} KOBE Range Hood
{B} Warranty Registration Card
{C} Quick Reference Guide
{D} 6” Round Exhaust with Rubber Plate x 1
{E} Baffle Filter x 2 (for 30”)
x 3 (for 36” and 42”)
{F} Flapper x 2
{G} Screws
{A} {B} {C}
{D} {E} {F}
{G}
•FOR MORE INFORMATION, PLEASE VISIT OUR WEBSITE www.koberangehoods.com OR
CONTACT KOBE RANGE HOODS AT 626-775-8880.
*knob is attached to the filters
Size: 4*16
QTY: 6pcs
Size: 4*35
QTY: 2pcs

4
(Must keep all materials for returns or refunds)
For Wall Mount Application
Model No.: RAX2130SQB-WM-1 (30”) / RAX2130SQB-WM-2 (30”)
RAX2136SQB-WM-1 (36”) /RAX2136SQB-WM-2 (36”)
RAX2142SQB-WM-1 (42”) / RAX2142SQB-WM-2 (42”)
Range Hood Box
{A} KOBE Range Hood
{B} Warranty Registration Card
{C} Quick Reference Guide
{D} 6” Round Exhaust with Rubber Plate x 1
{E} Baffle Filter x 2 (for 30”)
x 3 (for 36” and 42”)
{F} Flapper x 2
{G} Duct Cover
{H} Duct Cover-Mounting Bracket
{I} Screws
{A} {B} {C} {D}
{E} {F} {G} {H}
{I}
•FOR MORE INFORMATION, PLEASE VISIT OUR WEBSITE www.koberangehoods.com OR
CONTACT KOBE RANGE HOODS AT 626-775-8880.
*knob is attached to the filters
Size: 4*16
QTY: 6pcs
Size: 4*35
QTY: 4pcs
Size: 4*8
QTY: 2pcs

5
INSTALLATION
PLEASE READ ENTIRE INSTRUCTIONS BEFORE PROCEEDING
Calculation before Installation
To calculate installation, please refer to TABLE 1 and TABLE 2. (All calculations in inches).
- FOR UNDER THE CABINET -
TABLE 1
A = Height of Floor to Ceiling
B = Height of Floor to Counter Top
(Standard: 36”)
C = Preferred Height of Counter Top to
Hood Bottom (Minimum 26” to 30”)
D = Height of Hood
E = Height of the Cabinet
- FOR WALL MOUNT (WITH OPTIONAL DUCT COVER) -
TABLE 2
A = Height of Floor to Ceiling
B = Height of Floor to Counter Top
(Standard 36”)
C = Preferred Height of Counter Top to
Hood Bottom (Minimum 26” to 30”)
D = Height of Hood
E = Height of Duct Cover [F –D]
F = Height of the Hood Installation
[A –(B+C)]
SAFETY WARNING
•HOOD MAY HAVE SHARP EDGES; PLEASE WEAR PROTECTIVE GLOVES IF
REMOVING ANY PARTS FOR INSTALLING, CLEANING, OR SERVICING.
•BE CAREFUL WHEN USING ELECTRICAL SCREWDRIVER, DAMAGE TO THE
HOOD MAY OCCUR. USING HAND TOOLS IS RECOMMENDED. DO NOT OVER
TIGHTEN SCREWS.
•MAKE SURE TO PREVENT ANY DEBRIS FROM ENTERING THE VENT OPENING TO
AVOID DAMAGE OR MALFUCTION.

6
UNDER CABINET INSTALLATION
Before Installation
1. Read any provided document(s).
2. Test the range hood by temporarily connecting it to an outlet and turning ON the fan and lights.
3. If you run into any problems, contact KOBE Range Hoods.
Venting Requirements
4. The range hood has top 6” round exhaust (default).
5. Decided the location of the venting pipe from the hood to the outside. A straight, short vent run
will allow the hood to perform more efficiently. Try to avoid elbows, transitions, and long run as
much as possible as this may reduce the performance of the hood. Make sure that the duct work
leads to the outside.
6. It is recommended to use metal/aluminum duct/pipe with a uniform size (ex. 6” round pipe from
range hood to the outside).
7. If an elbow is necessary, a minimum of 12” straight run is necessary before the elbow.
Clearance
8. Clearance is the distance between the cooktop and the bottom of the range hood. The
recommended minimum clearance for this model is 26” and the maximum clearance is 30”.
9. It is important to install the hood at the recommended clearance. Installing too low could result in
damage and/or fire hazard while installing too high may result in reduced performance and
efficiently.
Hood Installation
10. Make sure the cabinet has full access opening for the
hood as shown on Figure 1.
11. Using reference on TABLE 1 and measurements on page
XX to mark the leveling point for hood-mounting bracket
inside the cabinet.
12. Secure two 4*35 screws (provided) inside the cabinet
leaving 1/8” away from the cabinet as shown on Figure 2.
13. Align hood-mounting bracket to the mounting screws
inside the cabinet and hook the hood into place. Secure
and tighten the mounting screws. (Figure 2).
Ductwork
14. Put the two flappers on 6” round exhaust vent adapter.
NOTE: striped side of the flapper is facing out.
15. Attached the rubber plate to the bottom of 6” round
exhaust vent adapter then attached to the exhaust
opening and use six 4*6 screws to secure it.
16. Use steel pipe to connect the 6” round exhaust on the
hood to the ductwork above. Use duct tape to make all
joints secure and air tight. Refer to Figure 3.
Figure 1
Figure 2

7
Electrical Wire
17. Connected the range hood to an outlet.
18. If hardware is desired, cut off the plug and connect three
wires (black, white, and green) to the outlet wires and cap
with wire connectors. Connect the wires according to color
(ex. black to black).
Finish
19. Remove any protective film from the hood, if any.
20. Before using, make sure that any accessories such as
baffle filters are properly installed where applicable.
21. Test the range hood to see if it is working properly.
THIS RANGE HOOD MUST BE PROPERLY GROUNDED. MAKE SURE THIS IS DONE BY
QUALIFIED ELECTRICIAN IN ACCORDANCE WITH ALL APPLICABLE NATIONAL AND LOCAL
ELECTRICAL CODES. BEFORE CONNECTING WIRES, SWITCH POWER OFF AT SERVICE PANEL
AND LOCK SERVICE PANEL TO PREVENT POWER FROM BEING SWITCHED ON ACCIDENTALLY.
Figure 3

8
WALL MOUNT INSTALLATION
Before Installation
1. Read any provided document(s).
2. Test the range hood by temporarily connecting it to an outlet and turning ON the fan and lights.
3. If you run into any problems, contact KOBE Range Hoods.
Venting Requirements
4. The range hood has top 6” round exhaust (default).
5. Decided the location of the venting pipe from the hood to the outside. A straight, short vent run
will allow the hood to perform more efficiently. Try to avoid elbows, transitions, and long run as
much as possible as this may reduce the performance of the hood. Make sure that the duct work
leads to the outside.
6. It is recommended to use metal/aluminum duct/pipe with a uniform size (ex. 6” round pipe from
range hood to the outside).
7. If an elbow is necessary, a minimum of 12” straight run is necessary before the elbow.
Clearance
8. Clearance is the distance between the cooktop and the bottom of the range hood. The
recommended minimum clearance for this model is 26” and the maximum clearance is 30”
9. It is important to install the hood at the recommended clearance. Installing too low could result in
damage and/or fire hazard while installing too high may result in reduced performance and
efficiently.
Hood Installation
10. Prepare back wall frame with cross framing lumber for
secure installation if necessary. Using references on
TABLE 2 and measurements on page XX to decide the
level of the lumber.
11. Mark the leveling point of the hood. Position two 4*35
screws on the wall, leaving 1/8” away from the wall as
shown in Figure 2.
12. Align hood-mounting bracket to the two screws on the wall
and hook the hood into place. Tighten screws to secure
hood to the wall.
Ductwork
13. Put the two flappers on 6” round exhaust vent adapter.
NOTE: Striped side of the flapper is facing out.
14. Attached the rubber plate to the bottom of 6” round
exhaust vent adapter then attached to the exhaust
opening and use six 4*16 screws to secure it.
15. Use steel pipe to connect the 6” round exhaust on the
hood to the ductwork above. Use duct tape to make all
joints secure and air tight.
Figure 1
Figure 2

9
Duct Cover Installation
16. Use reference E from TABLE 2 and measurements on
page XX to mark the position of the duct cover-mounting
bracket.
17. Secure the duct cover-mounting bracket to the wall with
two 4*35 screws. Make sure all screws are tightened.
Refer to Figure 3. NOTE: Inner duct cover will cover the
duct cover-mounting bracket.
18. Put the entire duct cover onto the hood and slide the inner
duct cover until it reaches to the duct cover-mounting
bracket.
19. Secure inner duct cover with two 4*8 screws to the duct
cover-mounting bracket. Shown in Figure 4.
Electrical Wire
20. Connect the range hood to an outlet.
21. If hardware is desired, cut off the plug and connect three
wires (black, white, and green) to the outlet wires and cap
with wire connectors. Connect the wires according to color
(ex. black to black).
Finish
22. Remove any protective film from the hood, if any.
23. Before using, make sure that any accessories such as
baffle filters are properly installed where applicable.
24. Test the range hood to see if it is working properly.
THIS RANGE HOOD MUST BE PROPERLY GROUNDED. MAKE SURE THIS IS DONE BY
QUALIFIED ELECTRICIAN IN ACCORDANCE WITH ALL APPLICABLE NATIONAL AND LOCAL
ELECTRICAL CODES. BEFORE CONNECTING WIRES, SWITCH POWER OFF AT SERVICE PANEL
AND LOCK SERVICE PANEL TO PREVENT POWER FROM BEING SWITCHED ON ACCIDENTALLY.
*Note: Sample image only. May not be actual
model.
Figure 3
*Note: Sample image only. May not be actual
model.
Figure 4

10
OPERATING INSTRUCTIONS
3-Speed Mechanical Push Button
NOTE: For best results, turn fan on prior to any preparation or cooking and keep fans running
while cooking. Adjust speed as needed.
To operate the fan function
•Press button to choose from speed
oQ = QuietMode™speed
oL = Low speed
oH = High speed
•Press “OFF” to turn fan off
To operate the light function
•Press the Light Control to turn lights on and off

11
MAINTENANCE
For optimal performance, clean the range hood surface and filters regularly.
To Clean Hood Surface
CAUTION: NEVER USE ABRASIVE CLEANERS, PADS, OR CLOTHS.
***Regular care will help preserve its fine appearance.
1. Use only mild soap or detergent solutions. Dry surfaces using soft cloth.
2. If hood looks smudged (stainless steel hood), use a stainless steel cleaner to clean the
surface of the hood. Avoid getting cleaning solution onto or into the control panel. Follow
directions of the stainless steel cleaner. Caution: Do not leave on too long as this may
cause damage to hood finish. Use soft towel to dry the hood.
3. DO NOT allow deposits to accumulate or remain on the hood.
4. DO NOT use ordinary steel wool or steel brushes. Small bits of steel may adhere to the
surface and cause rusting.
5. DO NOT allow salt solutions, disinfectants, bleaches, or cleaning compounds to remain
in contact with stainless steel for extended periods. Many of these compounds contain
chemicals, which may be harmful to the hood. Rinse with water after exposure and wipe
dry with a clean lint free cloth.
For Baffle Filter models only: to Clean Baffle Filters / Oil Tunnel
CAUTION: DRAIN OIL FROM BAFFLE FILTERS, SPACERS & OIL TUNNEL REGULARLY
TO PREVENT OVERFLOW.
1. Remove all the baffle filters, spacers and oil tunnel. NOTE: Not all models have spacers
and oil tunnel.
2. Using a sponge, washwith warm soapy water. Dry completely beforereturning into place.
CAUTION: SHARP EDGES
(NOTE: Baffle Filters are top rack dishwasher safe)

12
SPECIFICATIONS
MODEL / SIZE
Under Cabinet Model No. Wall Mount Model No.
RAX2130SQB-1 (30”) RAX2130SQB-WM-1 (30”)
RAX2136SQB-1 (36”) RAX2136SQB-WM-1 (36”)
RAX2142SQB-1 (42”) RAX2142SQB-WM-1 (42”)
RAX2130SQB-2 (30”)
RAX2136SQB-2 (36”)
RAX2142SQB-2 (42”)
COLOR
Commercial Grade Stainless Steel
CONSUMPTION / AMPERE
126W / 1.41A
VOLTAGE / Hz
110V / 60Hz
NUMBER OF BLOWERS
1
DESIGN
Seamless with Satin Finish
BLOWER TYPE
Single Horizontal Squirrel Cage
EXHAUST
Top 6” Round
CONTROL
Mechanical Push Button
LIGHT
3-watt LED Light x 2
HOOD DIMENSION
(W x D x H)
RAX2130SQB-2 29-3/4” x 20” x 12-3/16”
RAX2136SQB-2 35-3/4” x 20” x 12-3/16”
RAX2142SQB-2 41-3/4” x 20” x 12-3/16”
RAX2130SQB-WM-2 29-3/4” x 20” x (23-5/8” ~ 42-1/2”)
RAX2136SQB-WM-2 35-3/4” x 20” x (23-5/8” ~ 42-1/2”)
RAX2142SQB-WM-2 41-3/4” x 20” x (23-5/8” ~ 42-1/2”)
OPTIONAL ACCESSORIES
(W x D x H)
1. 30” Stainless Steel Back Panel
Model: SSP30 (30” x 32” x 1/10”)
2. 36” Stainless Steel Back Panel
Model: SSP36 (36” x 32” x 1/10”)
HOOD WEIGHT
Net
Gross
RAX2130SQB-2 / RAX2130SQB-2(30”)
30.0 lbs
37.0 lbs
RAX2136SQB-2 (36”)
33.0 lbs
41.0 lbs
RAX2142SQB-2
35.0 lbs
44.0 lbs
RAX2130SQB-WM-2 / RAX2130SQB-WM-2 (30”)
40.0 lbs
49.0 lbs
RAX2136SQB-WM-2 (36”)
44.0 lbs
53.0 lbs
RAX2142SQB-WM-2 (42”)
46.0 lbs
56.0 lbs
SPEED
QuietMode™
Low
High
Air Capacity (cfm)
320
500
700
Sone
1.0
2.2
5.0
*One sone is equivalent to the sound of a refrigerator at 40 decibels.
**Specifications subject to change without notice.

13
MEASUREMENTS & DIAGRAMS
***All inch measurements are converted from millimeters. Inch measurements are estimated.
***All measurements in ( ) are millimeters.
- FOR UNDER THE CABINET -
MODEL NO.: RAX2130SQB-2 (30”) / RAX2136SQB-2 (36”) / RAX2142SQB-2 (42”)
- FOR WALL MOUNT -
MODEL NO.: RAX2130SQB-WM-2 (30”) / RAX2136SQB-WM-2 (36”) / RAX2142SQB-WM-2 (42”)

14
PARTS LIST
MODEL NO.: RAX2130SQB-2 (30”)
RAX2136SQB-2 (36”)
RAX2142SQB-2 (42”)
No.
Description
Model No.
Part No.
01
6” Round Exhaust Adapter
02-028
02
Hood-Mounting Bracket
02-029
03
Capacitor
02-004
04
LED Light
02-005
05
Control Switch
02-006
06
Blower System
YYC-148-3
07
Baffle Filter
02-026
08
LED Light Driver
02-001

15
MODEL NO.: RAX2130SQB-WM-2 (30”)
RAX2136SQB-WM-2 (36”)
RAX2142SQB-WM-2 (42”)
No.
Description
Model No.
Part No.
01
Duct Cover-Mounting Bracket
02-039
02
Duct Cover
RAX21DC-2
03
6” Round Exhaust Adapter
02-028
04
Hood-Mounting Bracket
02-029
05
Capacitor
02-004
06
LED Light
02-005
07
Control Switch
02-006
08
Blower System
YYC-148-3
09
Baffle Filter
02-026
10
LED Light Driver
02-001

16
CIRCUIT DIAGRAM
MODEL NO.: RAX2130SQB-2 / RAX2130SQB-WM-2 (30”)
RAX2136SQB-2 / RAX2136SQB-WM-2 (36”)
RAX2142SQB-2 / RAX2142SQB-WM-2 (42”)

17
TROUBLE SHOOTING
Issue
Possible Cause
Solution
After
installation,
both motors
and lights are
not working.
The power is not on.
Make sure the circuit breaker and
the unit’s power is ON. Use a
voltage meter to check the power
supply.
The wire connection is not secure.
Check and tighten wire connection.
The control panel is defective.
Replace the control panel.
Lights are
working, but
motor(s) is
not.
The motor(s) is defective.
Replace the motor.
The capacitor(s) is defective.
Replace capacitor(s).
The control panel is defective.
Replace the control panel.
The range
hood is
vibrating.
The blower system is not secure.
Tighten the turbine impeller /
squirrel cage and air chamber.
The turbine impeller / squirrel cage is
not balanced.
Replace the turbine impeller /
squirrel cage.
Hood is not secured in place.
Check the installation of hood,
tighten the mounting bracket.
The motor is
working, but
the lights are
not working.
LED light fixture(s) is defective.
Replace LED light fixture(s).
The light wiring(s) is loose.
Check wire continuity from Control
Panel to LED Driver to LED light
fixture(s).
The control panel or LED light driver is
defective.
Replace the control panel or LED
light driver.
The range
hood is not
venting out
correctly.
The range hood is installed outside of
the manufacturer recommended
clearance.
Adjust the clearance between the
range hood and cook top to 26” to
30”. For island range hood, the
clearance between the range hood
and cook top is 30” to 36”.
There is no make-up air inside the
house.
Open the window to enhance the
performance of the range hood by
creating a sufficient make-up air.
Obstacle blocking the pipe work
Remove all obstacles from the
duct work.
The pipe size is smaller than the
suggested pipe size.
Change the ducting according to
the manufacturer suggestion.
Cold air is
coming into
the home.
The pipe connection is not properly
sealed.
Check the pipe installation.
The damper is not properly installed or
is missing from the installation
Check the damper installation.
The damper is not installed
Installing the damper will help
eliminate air backflow.