Mitek lt90 90 Degree Long Turn Dryer Elbow 4 Inch

Product Description

The MITEK lt90 is a 90-degree long-turn dryer exhaust elbow designed to replace the standard short-radius elbow used in residential dryer vent systems. Built from 26-gauge aluminized steel using a deep-drawn process, it measures 4 inches in diameter with a 10-inch radius and an 18-inch overall length. Engineering evaluation by Underwriters Laboratories confirmed this elbow to be 500% more efficient than a typical 3.5-inch radius elbow. The long-turn geometry reduces airflow restriction, adds up to 4.5 feet of effective duct run, and eliminates the need for a booster fan in most installations. HVAC technicians and dryer vent specialists install this fitting in attic runs and floor joist applications where tight bends create performance and lint-trap hazards.

The lt90 is suited for residential dryer exhaust venting routed through attic spaces or along floor joists where a standard 3-inch radius elbow creates excessive restriction. Its larger 10-inch radius and smooth interior surface reduce static pressure and lint accumulation compared to conventional short-radius fittings. The two-piece construction simplifies installation in tight spaces. Distinct male and female ends allow directional alignment during assembly, and the fitting accommodates standard 4-inch Snaplock rigid dryer duct. It is intended as a direct replacement for restrictive short-radius elbows where code-compliant duct run length is a limiting factor.

Key Features

• Long-turn 90-degree geometry with 10-inch radius for reduced airflow restriction
• UL engineering evaluation confirms 500% greater efficiency than a standard 3.5-inch radius elbow
• Adds up to 4.5 feet of effective duct run without a booster fan
• Two-piece construction with hook-and-twist fastening tabs for assembly in confined spaces
• Pre-drilled screw holes provide secondary mechanical fastening
• Notched fitting for exact Snaplock pipe engagement
• Deep-drawn 26-gauge aluminized steel construction for durability and heat resistance

Compatibility

Designed as a replacement for standard 4-inch diameter short-radius dryer exhaust elbows, including restrictive 3-inch radius fittings. Compatible with standard 4-inch Snaplock rigid dryer duct systems. Suitable for attic and floor joist dryer vent routing applications.

Installation Notes

Installation should be performed by a qualified HVAC technician or dryer vent specialist following applicable mechanical codes, including NFPA 211 and local authority requirements for dryer exhaust systems. Disconnect and unplug the dryer from its power source before beginning any duct work. Secure the elbow with the provided fastening tabs and pre-drilled screw holes, and verify all joints are sealed against lint and moisture intrusion. Do not use sheet metal screws that protrude into the duct interior, as they create lint accumulation points.

Technical Specifications

• Diameter: 4 inches
• Turn Radius: 10 inches
• Overall Length: 18 inches
• Bend Angle: 90 degrees
• Material: 26-gauge aluminized steel (deep-drawn)
• Construction: 2-piece with hook-and-twist fastening tabs and pre-drilled screw holes
• End Configuration: Distinct male and female ends
• Application: Dryer exhaust venting, attic or floor joist installation

Standard Information

• Brand: MITEK
• Manufacturer Part Number: lt90