KOBE Brillia CHX91 SQB-2 Series Troubleshooting guide

KOBE Range Hoods
Brillia Series
CHX91 SQB-2 Series
Model No.: CHX9130SQB-2 (30”)
CHX9136SQB-2 (36”)
INSTALLATION INSTRUCTIONS
AND OPERATION MANUAL

IMPORTANT
READ THIS FIRST
READ BEFORE INSTALLTAION
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 original 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
IMPORTANGE SAFETY INSTRUCTIONS .....................................................................1
COMPONENTS OF PACKAGE ......................................................................................3
INSTALLATION...............................................................................................................4
OPERATING INSTRUCTIONS .......................................................................................9
MAINTENANCE............................................................................................................10
SPECIFICATIONS ........................................................................................................11
MEASUREMENTS & DIAGRAMS.................................................................................12
PARTS LIST..................................................................................................................14
CIRCUIT DIAGRAM......................................................................................................15
TROUBLE SHOOTING.................................................................................................16
WARRANTY..................................................................................................................17
WARRANTY INFORMATION FORM............................................................................19
- 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
IMPORTANGE 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 warranty 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 extinguisher 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 on may cause ignition or an explosion.
5. Due to the size and weight of this hood, installation by 2 persons is recommended.
ELECTRICAL SHOCK HAZARD –Can result in serious injury or death.
Disconnected appliance from electric power before servicing. If
equipped, the fluorescent light bulb contains small amounts 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)
Range Hood Box
Duct Cover Box
(For Wall Mount Application Models Only)
{A} KOBE Range Hood
{B} Warranty Registration Card
{C} Quick Reference Guide
{D} 6” Round Vent Exhaust (Pre-Installed)
{E} 3-1/4” x 10” Exhaust
{F} Top Vent Cover with Rectangular
Opening
{G} Top Vent Cover (to block Round
Exhaust)
{H} Oil Tunnel x 1
{I} Baffle Filters x 2
{J} Stainless Steel Spacers x 2
{K} Screws
{A} {B} {C}
{D} {E} {F}
{G} {H} {I}
{J} {K}
{L} Adjust Duct Cover
{M} Duct Cover-Mounting Bracket
{N} Duct Cover Support x 2
{O} Hood-Mounting Bracket
{P} Screws
{L}
{M} {N}
{O}
{P}
•FOR MORE INFORMATION, PLEASE VISIT OUR WEBSITE www.koberangehoods.com OR
CONTACT KOBE RANGE HOODS AT 626-775-8880.
QTY: 6
Size: 4*8
QTY: 8
Size: 4*12
QTY: 5
Size: 4*35

4
INSTALLATION
PLEASE READ ENTIRE INSTRUCTIONS BEFORE PROCEEDING
Calculation before Installation
To calculate installation, please refer to TABLE 1 and TABLE 2. (All calculation 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.

5
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 Options and Requirements
4. The range hood has 3 exhaust options: Top 6” Round, Top
3-1/4” x 10” Rectangular, and Rear 3-1/4” x 10”
Rectangular. The range hood is factory set for vertical or
horizontal venting using round or rectangular vent adapter.
5. Decide 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.
8. For Top 6” Round vent installation: The 6” Round vent is
already attached. (Refer to Figure 1)
9. For Top 3-1/4” x 10” Rectangular vent installation only:
Remove attached 6” Round vent and discard. Keep seven
screws to install the rectangular vent. Align and secure
Top Vent Cover with RectangularOpeningwith one screw.
Then align and secure 3-1/4” x 10” Rectangular with two
screws. (Refer to Figure 2)
10. For Rear 3-1/4” x 10” Rectangular vent installation only:
Remove attached 6” Round vent and discard. Keep seven
screws to install the rectangular vent. Align and secure
Top Vent Cover with seven screws to block the top
exhaust (Figure 3). Remove the duct knockout from back
of the hood. Keep the screws and discard the duct
knockout. Then align and secure 3-1/4” x 10” Rectangular
with two screws (Figure 4).
Clearance
11. 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”.
12. 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 reduce
performance and efficiently.
*Note: 6” Round Vent Exhaust is pre-installed
on the range hood.
Figure 1
Figure 2
Figure 3

6
Hood Installation
13. Remove any protective film off the hood, if any.
14. For installing under the cabinet with recessed bottom,
attach 4-inch wide wood filler strips (not included) on each
side (Figure 5).
15. Create access opening for electrical plug or wires and
hood exhaust under the cabinet.
16. Align the hood in the center of the cabinet. As an optional
step, you may position a flat-surfaced object below the
hood as a support. Alternatively, another person can
temporarily hold the hood.
17. There are 4 installing holes on top of the hood. Attached
four 4*35 screws through the installing holes from the
bottom to the top. The best way is to do this in a diagonal
pattern: front left screw first then back right screw or vice
versa. Make sure all the screws are tightened and the
hood is secured before releasing hold/support.
18. Optional step: There areadditional 4 installing holes at the
back of the hood. Attached four 4*35 screws through the
installing holes from the front to the back. The best way is
to do this in a diagonal pattern. Make sure all the screws
are tightened and the hood is secured before releasing
hold/support.
Ductwork
19. Once the hood is attached to the cabinet, connect the pipe
onto the hood exhaust and secure the joint with duct tape.
Make sure that it is completely air tight.
Electrical Wire
20. Connect the range hood to an outlet.
21. If hardwired is desired, cut off the plug and connect three wires (black, white, green) to the outlet
wires and cap with wire connections (not provided). Connect the wires according to color (ex.
black to black).
Finish
22. Before using, make sure that any accessories such as filters are properly installed where
applicable.
23. 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 4
Figure 5

7
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 Options and Requirements
4. The range hood has 3 exhaust options: Top 6” Round, Top 3-1/4”
x 10” Rectangular, and Rear 3-1/4” x 10” Rectangular. The range
hood is factory set for vertical or horizontal venting using round or
rectangular vent adapter.
5. Decide 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.
8. For Top 6” Round vent installation: The 6” Round vent is already
installed. (Refer to Figure 1)
9. For Top 3-1/4” x 10” Rectangular vent installation only: Remove
attached 6” Round vent and discard. Keep seven screws to install
the rectangular vent. Align and secure Top Vent Cover with
Rectangular Opening with one screw. Then align and secure 3-
1/4” x 10” Rectangular with two screws. (Refer to Figure 2)
10. For Rear 3-1/4” x 10” Rectangular vent installation only: Remove
attached 6” Round vent and discard. Keep seven screws to install
the rectangular vent. Align and secure TopVent Cover with seven
screws to block the top exhaust (Figure 3). Remove the duct
knockout from back of the hood. Keep the screws and discard the
duct knockout. Then align and secure 3-1/4” x 10” Rectangular
with two screws (Figure 4).
Clearance
11. 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”.
12. 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
13. Secure hood-mounting bracket and two duct cover-mounting bracket support on top of the hood
with eight 4*12 screws. Refer to Figure 5.
*Note: 6” Round Vent Exhaust is pre-
installed on the range hood.
Figure 1
Figure 2
Figure 3
Figure 4

8
14. Using reference on TABLE 2 and measurements on page XX to
mark the leveling point of the hood. Position three 4*35 screws on
the wall, leaving 1/8” away from the wall as shown in Figure 6.
15. Align hood-mounting bracket to the three screws on the wall and
hook hood into place. Tighten screws to secure hood to the wall.
16. There are 4 installing holes at the back of the hood. Attached the
four 4*35 screws through the installing holes from the front to the
back. The best way is to do this in a diagonal pattern. Make sure
all the screws are tightened and the hood is secured before
releasing hold/support.
Ductwork
17. Use steel pipe to connect the exhaust on the hood to the
ductwork. Use duct tape to make all joints secure and air tight.
Duct Cover Installation
18. Use reference E from TABLE 2 and measurements on page XX
to mark the position of the duct cover- mounting bracket.
19. Secure the duct cover-mounting bracket to the wall with two 4*35
screws. Make sure all screws are tightened. NOTE: Inner duct
cover will cover the duct cover-mounting bracket. Refer to Figure
7.
20. Slide the entire duct cover onto the hood. Secure the outer duct
cover with four 4*8 screws to the duct cover support. Figure 8.
21. Slide the inner duct cover until it reaches to the duct cover-
mounting bracket. Secure inner duct cover with two 4*8 screws to
the duct cover-mounting bracket. Refer for Figure 9.
Electrical Wire
22. Connect the range hood to an outlet.
23. If hardwired is desired, cut off the plug and connect three wires
(black, white, green) to the outlet wires and cap with wire
connectors (not provided). Connect the wires according to color
(ex: black to black).
Finish
24. Remove any protective film from the hood, if any.
25. Before using, make sure that any accessories such as filters are
properly installed where applicable.
26. 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 5
Figure 6
Figure 7
Figure 8
Figure 9
*Note: Sample image only. May not be
actual model.

9
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

10
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 wipe off the cleaning solution, gently
rub off any stubborn spots. Use dry 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 or extended periods. Many of these compounds contain
chemicals, which may be harmful to hood. Rinse with water after exposure and wipe dry
with a clean lint free cloth.
For Baffle Filter models only: to Clean Baffle Filter / 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.
2. Using a sponge, washwith warm soapy water. Dry completely beforereturning into place.
CAUTION: SHARP EDGES
(NOTE: Baffle Filters are top rack dishwasher safe)

11
SPECIFICATIONS
MODEL / SIZE
CHX9130SQB-2 (30”)
CHX9136SQB-2 (36”)
COLOR
Commercial Grade Stainless Steel
CONSUMPTION / AMPERE
106W / 1.17A
VOLTAGE / Hz
110V / 60Hz
NUMBER OF BLOWER
2
DESIGN
Seamless / Satin Finish
BLOWER TYPE
Twin Vertical Turbine Impeller
EXHAUST
Top: 6” Round
3-1/4” x 10” Rectangular
Rear: 3-1/4” x 10” Rectangular
CONTROL
Mechanical Push Button
LIGHT
3-watt LED Light x 2
HOOD DIMENSION
(W x D x H)
CHX9130SQB-2 29-3/4” x 22” x 9-1/16”
CHX9136SQB-2 35-3/4” x 22” x 9-1/16”
OPTIONAL ACCESSORIES
(W x D x H)
1. 30” Stainless Steel Back Panel
Model No.: SSP30 (30” x 1/10” x 32”)
2. 36” Stainless Steel Back Panel
Model No.: SSP36 (36” x 1/10” x 32”)
HOOD WEIGHT (lbs)
Net
Gross
CHX9130SQB-2 (30”)
45.0 lbs
54.0 lbs
CHX9136SQB-2 (36”)
50.0 lbs
59.0 lbs
SPEED
QuietMode™
Low
High
Air Capacity (cfm)
306
428
600
Sone* (dB)
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.

12
MEASUREMENTS & DIAGRAMS
***All inch measurements are converted from millimeters. Inch measurements are estimated.
***All measurements in ( ) are millimeters.
- FOR UNDER THE CABINET -
MODEL NO.:
CHX9130SQB-2 (30”)
CHX9136SQB-2 (36”)
- FOR WALL MOUNT (WITH OPTIONAL DUCT COVER -
MODEL NO.:
CHX9130SQB-WM-2 (30”)
CHX9136SQB-WM-2 (36”)

13
***Hood-Mounting Bracket
***Duct Cover-Mounting Bracket
***Duct Cover Support

14
PARTS LIST
MODEL NO.:
CHX9130SQB-2 (30”)
CHX9136SQB-2 (36”)
NO.
DESCRIPTION
MODEL / SIZE
PART NO.
1
6” Round Exhaust Plate
02-030
2
3-1/4” x 10” Rectangular Exhaust
02-031
3
3-1/4” x 10” Top Vent Cover
02-032
4
Control Switch
02-006
5
LED Light
02-005
6
Capacitor (5uF) x 2
02-033
7
Metal Oil Tunnel
02-034
8
Left Motor
02-035A
9
Right Motor
02-035B
10
Left Impeller
02-036A
11
Right Impeller
02-036B
12
Spacer (33mm x 365mm)
02-038
13
Baffle Filter (322mm x 365mm)
02-037
Duct Cover (For Wall Mount Only)
NO.
DESCRIPTION
MODEL / SIZE
PART NO.
14
Duct Cover
15
Duct Cover-Support Bracket
02-039
16
Hood-Mounting Bracket
02-040

15
CIRCUIT DIAGRAM
MODEL NO.:
CHX9130SQB-2 (30”)
CHX9136SQB-2 (36”)

16
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(s).
The capacitor(s) is defective.
Replace the 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 light 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 manufacture recommended
clearance.
Adjust the clearance between the
range hood and cook top to 26” to
30”. For island range hood, the
distance between 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 from 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.