20
COLD AIR
RETURN
TO EXISTING
DUCT WORK
WARM AIR
EXISTING
FURNACE
MODEL 1321
FURNACE
FILTER BOX
APPENDIX
INSTALLATION A
NOTE:
INSTALL GRAVITY-TYPE BACKDRAFT DAMPERS IN THE 8" ROUND HEAT
OUTLET PIPES FOR SUPPLEMENTARY INSTALLS.
NOTE:
COMBINED STATIC PRESSURE IN OUTLET PLENUM MUST NOT EXCEED
0.25 INCHES WATER COLUMN WITH BOTH FURNACE'S FANS RUNNING.