Install Instructions

Installation Guidelines
Please note: DBF4XL fans are not
explosion proof.
Do not use the fans if a
potentially explosive situation may exist. DO NOT USE with heated air in
excess 140˚F (60˚C).
Do not install in an exhaust ductwork wher
e the equivalent duct length is <
25 feet (7.62 meters). The DBF4XL is suitable to overcome an equivalent
duct length of 130 feet (40 meters) of 4 inch diameter galvanized steel duct,
and to maintain a air velocity of 1200fpm (6.10 m/s).
Calculating Duct Run
To calculate the length of your planned duct run, measure from the dryer
to external venting point in roof or wall. For each bend or elbow add 5-7
feet to your total duct run calculations. The DBF4XL can be used on runs
up to 130 feet.
Fan and Switch Mounting
The DBF4XL is to be mounted a minimum of 5 linear (not equivalent) feet
from the dryer outlet. A secondary lint trap can be used in applications
where excessive dryer lint generation is likely or to increase the time inter-
val between routine maintenance of the Dryer Booster Fan. (See illustration
on right). A mounting bracket (included) attached to a rafter or joist should
be used to stabilize the fan. Although not recommended, a vertical rigid
duct may support the fan if the duct is securely stabilized. (Consult local
codes prior to supporting the fan in the duct alone.) It is recommended that
duct work be attached to the inlet and outlet of the fan by means of
FC vibra-
tion isolation clamps (optional) to permit periodic inspection of the blower.
Refer to maintenance instructions for inspection recommendations. All
duct connections should be properly sealed to prevent leakage and loss of
fan per
formance. Flex duct connections between the dryer duct connection
and exhaust duct should be stretched as smooth as possible.
Pressure Sensor Switch Operation
The DBF4XL contains a positive pr
essure sensing switch which r
ecognizes
dryer operation and activates the booster fan from an independent electrical
circuit. This eliminates connections through the dryer circuit which may void
the manufacturers’ warranty as well as manual systems which require the
attention of the operator or costly cur
r
ent/temperatur
e sensing systems.
Power to the booster fan is connected in series through a normally open ter-
minal on the switch. A pressure tap is connected to a nipple on the side of the
switch. When the dryer begins operation, positive pressure in the duct caus-
es the switch diaphragm to expand closing the circuit to the booster fan. An
integral delay-on-br
eak timer in the switch will cycle the fan on for intervals of
10 minutes. Cycle will reinitiate after a few seconds as long as the dryer is
operating. This will continue until the dr
yer has stopped and the timer delay
period has lapsed. Dr
ying cycles, the booster fan, the delay timer and the pr
es
-
sure switch are not adversely affected by the starting/stopping intervals.
DBF4XL
FC Mounting
Clamps (optional)
Alternate Location
Secondary Lint Trap
Installation Instructions for
Model DBF4XL Dryer Exhaust Booster
READ & SAVE THESE INSTRUCTIONS!
Includes:
1 DBF4XL Dryer Exhaust Booster
1 Fan Mounting Bracket and Hardware
1 Wall Label (Mount on wall near dryer.)
1 Tubing & Grommet