A Thermador hood pulling weakly, a blower gone loud, lights that stay off

Residential code requires a make-up air provision for kitchen hoods rated above 400 CFM. That threshold explains more hood complaints in newly built homes than any mechanical fault does. Houses built in Nocatee are constructed to modern envelope standards — they are tight. A powerful hood in a tight house cannot move air out unless something lets air in, so past a certain speed the blower simply works against the building.

The tell is physical: turn the hood to its highest setting and the back door pulls hard, or a nearby vented appliance changes note. That is not a broken hood. It is a hood with nowhere to draw from.

Weak extraction that really is the appliance

Once make-up air is ruled out, the list is short and mostly mechanical.

Baffle or mesh filters clogged with polymerised grease. These need real cleaning on a schedule, not a rinse — a filter that looks acceptable can still have lost most of its free area.

Blower wheel loaded with grease. A squirrel-cage wheel that has picked up an uneven coating loses efficiency and gains vibration at the same time, which is why weak extraction and new noise usually arrive together.

Ducting — and here one word has to be pinned down, because it is the word that makes people call the wrong trade. The duct we mean is the hood’s own run from the canopy to the cap outside: crushed flexible duct, a damper that no longer swings freely, or a roof or wall cap whose flap has seized shut. Nocatee homes are close together and hood runs are often short, which is good — but a short run with two tight elbows can still throttle a large blower. The home’s heating and cooling ducts are a different system with a different trade attached to it; we do not work on those, or on the furnace, heat pump or air handler feeding them.

Remote or inline blowers, mounted in the attic or on the roof, are common with larger hoods and are the ones nobody thinks to inspect. They are also where Florida attic heat and humidity go to work on motor bearings and wiring.

Noise diagnosis

A grinding or rumbling note that rises with speed is bearings. A rattle that appears at one speed only is usually the wheel or a loose duct joint resonating. A hum with no airflow is a motor that is energised but stalled, and running it in that state is how a motor winding is lost. Turn it off and call.

Lights, controls and boards

Halogen conversions, LED modules and the transformers behind them fail independently of the blower. So does the control board, which sits in one of the warmest, greasiest spots in the kitchen. Lights that work at one brightness setting only, or a panel that responds intermittently, are almost always electronic rather than lamp failures.

Downdraft units add a lift mechanism to all of this — a motor, a drive belt or screw, and limit switches. A downdraft that rises partway and stops is usually an obstruction or a limit switch, and forcing it damages the drive.

What a visit involves

We check filters and free area, pull and inspect the blower wheel, run the unit across all speeds while measuring current draw, check the damper and cap where they can be reached safely, and test lights and controls independently of the motor. If the problem is make-up air rather than the appliance, we will say so and explain the options rather than sell you a blower.

Flat $80 diagnostic, credited toward the repair when you approve the work, written estimate before any part is ordered. Genuine OEM parts, 90 days labor, 365 days parts.

Roof-mounted and attic-mounted blowers are quoted individually, because access is genuinely different in every house and we would rather price it after seeing it than guess on the phone. An attic visit for a remote hood blower is still a kitchen-appliance call: nothing else up there — air handler, plenum, refrigerant line, cooling duct — is work we take on.