The Suburban 232261 Sail Switch is a low-airflow switch designed for SF Series RV furnaces. If the fan on your furnace runs but no heat is flowing, you may have to replace the sail switch. Fits Suburban Furnace Models SF-20, 25, 30, 35, 42; SF-20F, 25F, 30F, 35F, 42F; SH-42, 42F. | Suburban RV Furnace Sail Switch for SF Series, 232261