MGD Series Gas Furnace Installation Instructions
Heat Controller, Inc. Jackson, MI 49203 MGD Installation Instructions 4
RETURN AIR
ALCOVE INSTRUCTION
The furnace may be installed free standing or in an
alcove with a free flow of air back to the furnace. A
minimum of 18” shall be provided at the front for
return air and service access.
CLOSET INSTALLATION – 6 in.
Note: If return air is through a side wall, there must
be a minimum of 6-in. clearance from side wall to
furnace in addition to 6-in. minimum clearance from
inside of closet door to front of furnace.
If a louvered door complying with the minimum air
requirements is used, the front clearance my be reduced to
1”.
CLOSET INSTALLATIONS
Additional Requirements
Concerning under floor or ceiling return air systems,
the following item (1 – 10) must be adhered to:
1. The return-air opening into the closet, regardless
of location, is to be sized not less than specified
on the appliance rating plate.
2. If the return-air opening is located in the floor of
the closet (versus the vertical front or side wall),
the opening is to be provided with means to
prevent its inadvertent closure by a flat object
placed over the opening.
3. The cross-sectional area of the return system
(when located in the floor or ceiling of the
manufactured home) leading into the closet is to
be not less than that of the opening specified on
the appliances rating plate.
4. The total free area of openings in the floor or
ceiling registers serving the return-air duct
system is to be not less than 150% of the size
opening specified on the appliance rating plate.
At least one such register is to be located where
the likelihood of its being covered by carpeting,
boxes, and other objects is minimized.
5. Materials located in the return duct system have
a flame spread classification of 200 or less.
6. Non-combustible pans having one-inch upturned
flanges are located beneath openings in the floor
return duct system.
7. Wiring materials located in the return duct system
conform to Article 300-22 (B&C) of the National
Electric Code, ANSI / NFPA-70.
8. Gas piping is not run in or through the return duct
system.
9. The negative pressure in the closet, as determined by
test with the air-circulating fan operating at high
heating speed and the closet door closed, is to be not
more negative than minus 0.05-inch water column.
10. For floor return systems, the manufactured home
manufacturer or installer shall affix a prominent
warning where it is easily read when the closet door
is open.
The marking shall read:
