Elbow Configurations; Vent Terminal Configurations; Deductions From Maximum Equivalent Vent Length - Carrier 986TC Installation, Start-Up, Operating And Service And Maintenance Instructions
Two--stage, variable--speed multipoise 35 in. (889 mm) tall condensing gas furnace
1. Use only the smallest diameter pipe possible for venting. Over ---sizing may cause flame disturbance or excessive vent terminal icing or freeze ---up.
2. NA --- Not allowed. Pressure switch will not close, or flame disturbance may result.
3. Vent sizing for Canadian installations over 4500 ft. (1370 M) above sea level are subject to acceptance by the local authorities having jurisdiction.
4. Size both the combustion air and vent pipe independently, then use the larger size for both pipes.
5. Assume the two 45_ elbows equal one 90_ elbow. Wide radius elbows are desirable and may be required in some cases.
6. Elbow and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
7. The minimum pipe length is 5 ft. (2 M) linear feet (meters) for all applications.
8. Use 3 ---in. (76 mm) diameter vent termination kit for installations requiring 4 ---in. (102 mm) diameter pipe.
Mitered
Table 17 – Deductions from Maximum Equivalent Vent Length - - Ft. (M)