Westinghouse 903658 Furnace Roof Jack 15-23 in Aluminized Steel

Product Description

The WESTINGHOUSE 903658 is an aluminized steel roof jack designed for venting residential gas furnaces through rooftop penetrations. Spanning an adjustable length of 15 to 23 inches, it accommodates a range of roof thicknesses and pitches without additional adapters. The unit ships with a flat flashing rated for a 12-inch rise, providing a weather-tight seal at the roof deck. Constructed from aluminized flue steel, it offers durable corrosion resistance in high-temperature exhaust environments. This component is installed by licensed HVAC technicians as part of a B-vent or single-wall flue system termination.

The 903658 roof jack is specified for use with WESTINGHOUSE MG, MB, MS, MM, and M1 series gas furnaces. It is suited to residential installations where the flue must exit through the roof plane rather than a sidewall. The adjustable length range makes it adaptable to standard residential roof assemblies of varying depth, and the included flat flashing integrates with common roofing materials during installation.

Key Features

• Adjustable length from 15 to 23 inches to fit varying roof thicknesses
• Aluminized flue steel construction for corrosion and heat resistance
• Includes flat flashing with 12-inch rise for weather-tight roof penetration
• Non-transit design — intended for permanent installed use
• Compatible with MG, MB, MS, MM, and M1 series furnace flue systems

Compatibility

Designed for use with WESTINGHOUSE MG, MB, MS, MM, and M1 series furnaces as stated by the manufacturer.

Installation Notes

Installation should be performed by a licensed HVAC technician in accordance with local mechanical codes and the appliance manufacturer's venting instructions. Shut down and isolate the furnace from gas and electrical supply before beginning any flue work. The flashing should be integrated into the roof membrane according to roofing best practices to prevent water infiltration. Verify the final assembly meets clearance-to-combustibles requirements per the appliance listing and applicable code.

Technical Specifications

• Type: Roof Jack, Non-Transit
• Adjustable Length: 15 to 23 inches
• Flashing Style: Flat with 12-inch rise
• Material: Aluminized Flue Steel

Standard Information

• Brand: WESTINGHOUSE
• Manufacturer Part Number: 903658