Thermo Products CMC1-75D36N, CMC1-50DV3N, CMC1-50D36N, CMA3-50D36N CMA3 SERIES, CMC1 SERIES

All installations and services must be performed by qualified service personnel.

CMA3 SERIES CMC1 SERIES

Figure 5.

: Do not obstruct any return air openings, including the return grille on the furnace. To do so may cause the furnace to activate the high limit and shut down.

3.The cross-sectional area of the return system leading into the closet (when located in the floor or ceiling) shall not be less than 250 square inches.

4.The total free area of openings in the floor or ceiling registers serving the return duct system must be at least 350 square inches. At least one register must be located where it is not likely to be covered by carpeting, boxes, furniture or other objects.

5.Materials located in the return duct system must have a flame spread classification of 200 or less.

6.Non-combustible pans having one inch upturned flanges are to be located beneath openings in a floor return duct system.

7.Wiring materials located in the return duct system must conform to articles 300-22 of the National Electrical Code NFPA70 (Latest Edition).

8.Gas piping is not to be located in or through the return duct system.

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