If flanged sheet metal ducts are metal-screwed to the unit
casing, do not use screws longer than 1/2 in.
Airflow across air cleaner must be uniform for best results.
Install turning vanes if air cleaner is installed close to an
elbow. Depending on size of furnace, it may or may not be
necessary to reduce ductwork on leaving-air side of air
cleaner. For any application, maintain a 3-to-1 duct reduction
ratio (3 in. of duct length for every 1-in. of reduction in size).
Do not baffle any portion of the entering-air side of the air
cleaner.
9. Seal all joints on downstream side of air cleaner to prevent
infiltration of contaminated air.
Step 3—Electrical Connections
All wiring must comply with applicable local and national codes.
Determine best power wiring routing refer to Section A for
Internal Electrical Connections and Section B for External Elec-
trical Connections.
Fig. 4—Typical Applications
A86134
DOWNFLOW APPLICATION
RETURN AIR
PLENUM
FAN-COIL
UNIT
SUPPLY AIR
PLENUM
ELECTRONIC
AIR CLEANER
A91468
SUPPLY AIR
PLENUM
COOLING
COIL
UPFLOW
FURNACE
ELECTRONIC
AIR CLEANER
RETURN AIR
PLATFORM
GAS SUPPLY
UPFLOW APPLICATION
A91470
VENT
RETURN
AIR PLENUM
ELECTRONIC
AIR CLEANER
HORIZONTAL
FURNACE
SERVICE
PLATFORM
SUPPLY
AIR PLENUM
HORIZONTAL FURNACE APPLICATION
A91469
UPFLOW
FURNACE
3 TO 1
TRANSITION
DUCT WORK
ALTERNATE
AIR CLEANER
POSITION
AIRFLOW
ELECTRONIC
AIR CLEANER
COOLING
COIL
FURNACE SIDE APPLICATION
4
