MC Enterprises 36165MC Sail Switch | Normally-Closed Furnace Air-Flow Switch

The MC Enterprises 36165MC is a replacement sail switch designed to monitor combustion air flow inside an RV furnace assembly. It uses a normally-closed contact so the furnace control board can confirm air is moving through the compartment before allowing ignition, an important safety check on forced-air furnace systems.

Built from metal with screw terminals for a secure wire connection, this compact switch (about 4 x 1 x 0.5 inches) is sized to drop into the same tight mounting locations as the switch it's replacing, making it a straightforward part for anyone troubleshooting a furnace that won't stay lit.

• Normally-closed contact confirms air flow before burner ignition
• Screw-terminal connections for a solid, serviceable wire hookup
• Durable metal housing suited to furnace compartment conditions
• Compact 4 x 1 x 0.5 in. footprint fits factory mounting locations
• Door-mount design for installation inside the furnace housing
• Manual-reset limit switch operation

If a furnace is cycling on lockout or won't ignite, a worn or stuck sail switch is a common culprit, and this replacement gets the air-proving circuit back to spec.