NO GRAVEL UNDER SLAB SYSTEM
High Pressure system – Note properly installed weatherproof switch and UF-B outdoor wire. Properly installed outdoor on/off switches provide a means
to disconnect power for the fan from the outside. There is no need to cut power at the circuit breaker inside the house in order to change the fan after it’s useful life. This is a National Mechanical Code requirement for outdoor fan installations.
Also, note that all wall penetrations are neatly sealed with permanent polyurethane sealant.