Product Description

The WESTINGHOUSE 903660 is an aluminized steel furnace roof jack designed for venting residential gas furnaces through the roof. This non-transit unit provides an adjustable length range of 27 to 47 inches, allowing installers to accommodate varying roof depths and rafter configurations without cutting to a fixed dimension. The included flat flashing with a 12-inch rise is integrated into the assembly, creating a weather-tight seal at the roof deck penetration. Licensed HVAC technicians and sheet metal contractors typically handle this type of B-vent termination hardware during new installations and replacements.

This roof jack is specified for use with MG, MB, MS, MM, and M1 series furnace applications. Its adjustable length makes it well suited for residential installations where attic depth or rafter spacing varies from one structure to the next. The flat flashing profile is appropriate for low-slope or flat roof installations where the 12-inch rise provides adequate clearance and drainage diversion at the penetration point. The aluminized steel construction resists the high-temperature flue gases and condensation common in residential forced-air gas furnace venting systems.

Key Features

Adjustable length from 27 to 47 inches to fit varying roof depths and rafter configurations
Aluminized steel construction for resistance to heat and flue gas condensation
Integrated flat flashing with 12-inch rise for a weather-tight roof penetration seal
Non-transit design for permanent installation applications
Compatible with MG, MB, MS, MM, and M1 series furnace venting configurations

Compatibility

Specified for MG, MB, MS, MM, and M1 series furnace applications requiring a roof jack termination assembly with flat flashing.

Installation Notes

Installation of this roof jack must be performed by a qualified HVAC technician or licensed contractor in accordance with the International Fuel Gas Code (IFGC) and local amendments. Shut down and lock out the furnace before beginning any work on the venting system. The flashing must be properly integrated with the roofing material to prevent water infiltration at the penetration point. Confirm that the final installed length, flue clearances, and termination height meet the appliance manufacturer specifications and local code requirements before returning the system to service.

Technical Specifications

Adjustable Length: 27 to 47 inches
Material: Aluminized Steel
Flashing Type: Flat
Flashing Rise: 12 inches
Design Type: Non-Transit

Standard Information

Brand: WESTINGHOUSE
Manufacturer Part Number: 903660

Brand	WESTINGHOUSE
MPN	903660

Westinghouse 903660 Furnace Roof Jack 27-47" Aluminized Steel

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