LG's range hoods are wall-mount chimney hoods with metal grease filters, LED lighting and a multi-speed blower. They are simple machines that live in a hostile place, directly above a cooktop that throws grease, steam and heat at them every evening. The care they need is modest, and the failures they suffer follow from skipping it.
The Grease Filters
The filters catch airborne grease before it reaches the blower and the duct. As they load, airflow drops, the blower works harder and noisier, and grease begins to pass through to the duct. Release the filters by their latches, with the hood switched off and the cooktop cold so nothing is hot above your head, and wash them in hot water with a degreasing detergent or in the dishwasher if the manual for your model allows. Let them dry fully before refitting, and refit them square so the latch clicks; a filter sitting on one latch rattles at every speed. If dinner is cooked at home most evenings, once a month is a sensible rhythm, and frying shortens it.
Why Grease in a Hood Is a Fire Matter
A filter saturated with grease sits above the burners, and a duct coated in grease carries any flame straight into the wall or ceiling. This is not a performance point. A flare-up on the cooktop under a neglected hood has fuel waiting for it. Clean filters keep the grease where it can be washed off.
Recirculating Hoods
A hood installed without a duct to the outside passes air through a charcoal filter and returns it to the room. Charcoal filters are replaced, not washed; washing them destroys the charcoal and returns a filter that looks clean and does nothing. The interval is in the manual and shortens with heavy cooking.
The Lights
LG hoods use LED modules that dim and fail over years rather than burn out suddenly. Before touching a light, switch the hood off at its breaker, because the fixture is wired into the hood's mains supply and the on-off switch on the hood does not isolate it. Some modules are replaceable from below by hand; others are part of a light assembly that is a technician job. The manual for your model says which.
The Fan
A rattle that comes and goes with fan speed is usually a filter, a loose chimney cover or the damper flap in the duct above the hood knocking in the airflow. A hum with little air is a blocked duct or a damper stuck shut; the flap at the outside wall can be jammed with grease or a nest. A grinding or scraping that rises with speed is the blower bearing or a blade touching its housing, and that is reached only with the hood off at the breaker and the blower housing opened, which is a visit. So is a blower that runs on one speed only or not at all when the lights still work, which points at the switch or control board.
The Controls
Touch controls on a hood collect a grease film that makes them slow or erratic. Wipe them with a cloth barely damp with degreaser, then dry, with the hood switched off. Do not spray cleaner directly at the panel.
Booking It
For a blower noise, a dead speed, or a light module that is not a simple swap, book an LG range hood repair with the model number from the plate inside the hood behind the filters, and say whether the hood is ducted or recirculating.