Loud Viking Hood, Room Full of Smoke

The complaint arrives in one sentence, almost word for word every time: the hood is loud but the smoke still comes at me. It is a good description and it points straight at the answer, because noise and airflow are not the same thing.

A blower makes most of its noise from the motor and from air moving through the housing. It will happily make all of that noise while moving very little air, if something downstream or upstream will not let the air through. Which is why the first question is never “is the motor working” but “where is the air stuck”.

Free test number one: the filters

Baffle filters lose free area as grease loads them, and they do it gradually enough that nobody notices. A set of filters that have gone dull and slightly tacky are restricting the system meaningfully. Most of them come back with a dishwasher cycle and a degreaser.

If cleaning the filters changes the capture, that was the whole problem. We would rather tell you that on the phone than charge you to discover it.

Free test number two: open a window

If the filters are clean and capture is still poor, crack a window near the kitchen and run the hood again. If the smoke suddenly starts going up the hood, the blower is fine. The house is the problem.

Here is the mechanism. A high-capacity hood removes a real volume of air from the building. That air has to be replaced, and it will be replaced through whatever openings exist. In a tightly built house — most newer construction in the Deerwood, Baymeadows and Bartram Park corridor — there are very few openings, so the blower ends up working against a partial vacuum. Fan curves fall off steeply under pressure. The motor draws its current, makes its noise, and moves a fraction of its rated air.

Cracking a window supplies make-up air by hand and proves it in thirty seconds.

The permanent fix is a make-up air path, which is mechanical contracting and not appliance repair. We do not do that work — heating, air conditioning, air handlers and the ducts that serve the house are a different trade, and the only duct we open is the one carrying cooking smoke out of the kitchen. It is also the thing that will actually solve the problem, so we say it rather than selling a blower.

When the duct is the problem instead

The opposite case shows up in Riverside, Avondale, Old Ortega and San Marco. A 1915 frame house leaks enough air that make-up is never the constraint. There the constraint is the duct run, because there was rarely a short straight path from the cooktop to an exterior wall through plaster and lath and a century of additions.

Long runs, multiple elbows and any reduction in diameter all cost static pressure. A duct that has been squeezed down to fit a joist bay is a permanent restriction, and no blower fixes it. We look at the run, count the turns and check the diameter before quoting anything.

What actually is a motor fault

There is a real motor failure and it sounds different. Bearing wear produces a rumble or hum that appears at one speed and vanishes at another, because the resonance only lines up at certain revolutions. That is a motor on borrowed time and it will usually seize during the week you need it most.

Losing the middle speeds while the top and bottom still work is a control fault, not a motor fault — a dead motor is dead at every setting. Lights working while the fan does nothing proves power is reaching the hood, which is worth establishing before anyone opens a wall.

The damper nobody checks

Backdraft dampers live out of sight in the duct and they stick. One that will not open throttles the entire system while everything visible looks perfect. One that will not close lets humid outside air, and sometimes insects, back down into the kitchen, which in a Jacksonville August is a problem of its own.

We check it. It is a small thing that explains a lot of hoods that have never worked properly since the day they were installed.

Flat diagnostic, credited toward the repair. Written estimate first.