Look for water pooling in the burner compartment or signs of white calcification (corrosion) on the exterior of the box

and bypass loops in hydronic systems with variable or constant flow

system lockout with specific error codes

Standard industry practice for commercial HVAC maintenance suggests inspecting the strainer during annual teardowns or whenever the refrigerant charge is pulled to ensure no debris has accumulated

blocked flue

Trane FAN0517 Steel Wheel 30067439-890 Look for water pooling inThe Trane FAN0517 is a heavy duty, field proven 8 x 9" CW Steel Wheel engineered for precise airflow management in commercial and residential air handling units. Featuring a 1. 25" bore, this direct drive blower component is constructed from high grade galvanized steel to resist deformation under high static pressure. The clockwise rotation (CW) design ensures optimal centrifugal force for consistent CFM delivery. Designed as a genuine OEM replacement