Alpha Return Air Restriction / High Static Pressure

Furnace is very loud at the return grille, with a whistling or roaring sound.

Possible Causes

Filter too restrictive or installed backwards, Undersized return ductwork, Blocked return grilles, Closed doors reducing return airflow

Safety: Turn off power before changing filters.

Check filter: Ensure the filter is installed in the correct direction (arrow toward furnace) and is not overly restrictive for your Alpha model.
Open returns: Make sure all return grilles are open and not blocked by furniture.
Interior doors: Keep doors open or undercut to allow air to return to the furnace.

Persistent noise may indicate duct design issues that require professional evaluation.

Very Easy 1/5