33082 Sail Switch with Bracket - Pack of 2

Key Features

• Airflow Safety Sensing: Designed to detect sufficient blower motor speed by reacting to the "wind" (airflow) inside the furnace; if the sail does not move, the furnace will not ignite, preventing overheating.
• Precision Microswitch: Features a high-sensitivity internal switch that closes the circuit only when the blower reaches the RPM threshold required for safe combustion.
• Corrosion-Resistant Bracket: Includes a pre-attached metal mounting bracket designed for a direct fit, ensuring the switch is positioned at the optimal angle within the air plenum.
• High-Temperature Housing: The switch body is constructed from heat-stabilized materials to maintain electrical integrity within the intense thermal environment of an RV furnace.
• Integrated Large Sail: Features the "Large Sail" design (M/L Kit) to ensure reliable engagement even in systems with slightly reduced airflow or older blower motors.

Replaces / Cross-Reference Part Numbers

• 33082
• Atwood 33082
• Dometic 33082
• SVC Df Sail Sw W/Brkt M/L Kit
• 33081 (Switch only)

Compatibility & Fitment

This sail switch is a standard replacement for many Dometic and Atwood RV furnaces. Key compatible series include:

• Atwood/Dometic DF Series: DFMD20, DFMD25, DFMD30, DFMD35 (Medium/Large).
• Atwood/Dometic AF Series: AFMD20, AFMD25, AFMD30, AFMD35.
• Small Furnace Compatibility: While primarily for Medium/Large (M/L) models, it replaces switches in many newer Dometic digital-controlled furnaces.
• Note: Not compatible with older "Hydro Flame" 8500-IV series furnaces that use the smaller, square sail design.

When to Replace

• Blower Runs but No Heat: The furnace fan turns on, but you never hear the "click" of the gas valve or the "tick-tick-tick" of the igniter.
• Intermittent Ignition: The furnace sometimes lights but often fails, which can be caused by a bent sail or a weak internal microswitch spring.
• Physical Damage: The thin metal sail is bent, crimped, or missing, preventing it from catching enough air to move the switch.
• Lint/Debris Build-up: Excessive dust or pet hair has clogged the switch pivot point, making the sail too "heavy" to move under normal blower pressure.

Installation Tips

• Accessing the Switch: Most modern DF series furnaces require removing the exterior access cover; the sail switch is typically located on the side of the blower housing.
• Orientation: Note the direction of the old sail before removal. The "sail" (the thin metal flap) must be facing into the path of the blower air.
• Wire Connections: The two wires can generally be connected to either terminal on the switch, as it is a simple "normally open" circuit that closes when air pushes the sail.
• Clearance Check: Once mounted, gently push the sail with your finger to ensure it moves freely and clicks the microswitch without hitting the sides of the mounting slot.
• Test the Blower: If a new switch doesn't fix the issue, check your battery voltage or blower motor speed; if the motor is spinning too slowly, it won't produce enough air to move even a brand-new sail switch.