Closet and Alcove Installation
All furnace models covered in this manual may be installed in a closet or alcove
with specified (standard) clearances to combustible construction. When installed
in a counterflow configuration a combustible surface-mounting base (Model # D6-
BASE) must be used for when installing on combustible materials, refer to Figure
1.
Figure 1: Counterflow Furnace Combustible Surface-Mounting Base
Standard Clearances
Standard clearances are mandatory minimum clearances from heated surfaces
of the furnace to combustible materials to assure protection from fire hazard
during furnace operation. (Refer to the Standard for the Installation of Oil-Burning
Equipment, NFPA 31-2020, or latest edition, for definitions of combustible and
non-combustible materials.
Accessibility clearances, which are typically greater, may exceed fire protection
clearances. Therefore, consider providing at least 24 inches of clearance from
the front of the furnace to obstructions and surfaces for adequate service and
maintenance access.
The minimum clearances from furnace casing surfaces to combustible materials
are:
0 inches from casing sides and rear
6 inches from front casing of furnace
7 inches from flue pipe/vent connector
1 inches from casing top
1 inches from any side of supply air plenum
1 inches above supply air ducts, within 6 feet of furnace
6