Ventilation hood: weak capture, rattle, dead blower

A hood has one job — move air out of the room — and on the barrier island it does that job with air that carries chloride. Nothing else in the kitchen has that duty cycle across bare metal, which is why the hood is the appliance we get called about most often here and why it fails in a predictable order.

Rattle and hum

The first complaint is almost always noise, and the cause is almost always the blower wheel. Grease and salt film build unevenly on the blades. A flake comes off one side, the wheel is out of balance, and you hear it at the speed you use least often. Nothing is broken at this point. A wheel clean and a balance check is a small job.

Left alone, an unbalanced wheel loads the motor bearings continuously. Bearing noise is different — a dry whirr or a growl that does not change when the wheel is cleaned — and it means the blower assembly is on the clock.

Weak capture

The second complaint is that the hood no longer catches. People blame the cook, or the pan, or the recipe. Usually it is one of three things.

Baffle filters that have stopped filtering. If you cannot see light through the baffles, they are not separating grease, they are storing it, and they are a restriction. They are dishwasher-safe by design and most people wash them far too rarely.

A fouled or corroded wheel moving less air than it is rated for. Same wheel, same motor, less flow.

Or make-up air. A tight, well-sealed house cannot exhaust what it cannot replace. A high-capacity hood in a modern sealed build will pull itself into a stall unless something lets air back in. Older beach cottages leak enough to feed a hood by accident; new construction in South Jacksonville Beach often does not, and that is an installation issue rather than an appliance fault.

The housing and the ductwork

Behind the baffles, the housing and the duct collar are where salt does its quiet work. Rust bloom on a galvanised seam is the visible stage; by then the coating is already gone. Where the blower is remote — in-line in the attic or mounted on the exterior wall — exposure is worse again, and an exterior blower housing on the ocean side of a house ages faster than the same unit two miles west. That is not a defect, it is the address.

We also check the roof or wall cap. A damper that has corroded partly shut, or a screen that has clogged with lint and salt crust, throttles the whole system while the hood itself tests perfectly.

Controls and speed faults

A hood stuck on one speed, or unresponsive to the controls, is usually the control board, the speed control, or the harness between them. Salt film across a switch body or a connector shell gives current a path it should not have. We check for corrosion at every connector before condemning a board, because a cleaned and re-terminated connection is a far better outcome than a board that will fail again for the same reason.

What the visit looks like

We pull the baffles, inspect and photograph the wheel and housing, check bearing condition by hand and by sound, test each speed at the control, verify the damper opens fully, and measure what the hood is actually drawing at the capture edge rather than what the badge claims. Then you get a written estimate.

Call at the rattle stage. A wheel clean and a housing inspection is a modest visit; a seized blower behind a rusted-through housing is a parts job, and coastal kitchens get there sooner than anyone expects.