Thermo Pride Gas/Propane Furnace Mobile Home CMC1 - Manual (Page 17)

All installations and services must be performed by qualified service personnel.
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B. BASE INSTALLATION – CMA3 models only
1. Combustible Floor Base Model: 70 BASE (for CMA3 models only)
Use the base bottom panel as a template to mark floor opening locations (see
Figure 2). Cut a square opening in the floor for the supply air connector duct. Cut
the opening 1-inch larger than the square template opening. (duct requires 1-inch
clearance to combustible floor).
Figure 2.
Figure 3.