11RETURN AIR TEMPERATUREThis furnace is designed for continuous return--air minimum temperature of 60_F (15_C) db or intermittent operation down to 55_F (13_C)db such as when used with a night setback thermometer. Return--air temperature must not exceed 80_F (27_C) db. Failure to follow thesereturn air limits may affect reliability of heat exchangers, motors and controls.6080 / 27˚C/ 16˚CSUPPLY AIRA10490MINIMUM CLEARANCES TO COMBUSTIBLE MATERIALSPOSITION CLEARANCERear 0 (0 mm)Front (Combustion air openings in furnace and in structure) 1 in. (25 mm)Required for service** 24 in. (610 mm)*All Sides of Supply Plenum** 1 in. (25 mm)Sides 0 (0 mm)Vent 0 (0 mm)Top of Furnace 1 in. (25 mm)* Recommended**Consult your local building codesCOMBUSTION--AIR PIPE FOR NON--DIRECT (1--PIPE) VENT APPLICATIONFIELD-SUPPLIED2-IN. (51 mm) DIA.PVC PIPEFIELD-SUPPLIED2-IN. (51 mm) DIA.MITERED RADIUSPVC 90° ELBOW12” (300 mm) MINIMUMA12376NOTE: See Installation Instructions for specific venting configurations.59SP5A