---
title: "Range hood not clearing the kitchen"
description: "A hood that sounds like it is working and is not clearing anything. Nine times in ten the duct is to blame rather than the appliance, and the test that"
url: "https://askomiami.support/symptoms/hood-not-extracting/"
date_modified: "2026-09-13"
Appliance type: "Range hoods"
---


# Asko range hood not clearing the kitchen

### What to do in the next ten minutes

Turn the hood to full and go outside to the vent. Hold a tissue near it: if nothing moves, nothing inside the hood is the problem. Then take the grease filters out, wash them in the dishwasher, and look at the impeller behind them — a fan loaded with grease moves a fraction of the air it should and sounds perfectly normal doing it.

### Why there is nothing to look up

The CG1, CO4927S and CBB901SB manuals were read in full and not one of them has a troubleshooting section — not a thin one, not a symptom table, none. So everything on this page comes from what actually fails on a hood rather than from a document, and we would rather say that plainly than imply a source that does not exist.

### The damper nobody checks

Where the duct leaves the building there is usually a backdraft damper, a light flap that opens under airflow and closes against wind and rain. On a coast it corrodes, and a damper that has stopped opening ends extraction completely while the hood carries on sounding exactly as it always did. It is minutes to free while it still moves and a part once it does not.

The duct run is the problem

Too long, too narrow, full of grease, or ending at a damper that has salted shut. A liner moving air correctly into a bad duct sounds exactly like one that works.

The impeller is loaded with grease

Gradual, so people notice it as a change rather than a defect. Filters through the dishwasher and the impeller cleaned properly recover most of it.

The motor or its capacitor is weak

Measured under load rather than judged by sound, because a hood that runs is not necessarily a hood that is working.

Does anything leave the outside vent?

One minute, one tissue, and it decides whether this is an appliance problem at all.

When were the filters last washed?

They go in the dishwasher. If the answer is never, that is where this starts.

Is it recirculating rather than ducted?

Some are, and then nothing leaves the building by design. Worth establishing before anybody looks for a blockage that does not exist.

It runs, and the steam still goes everywhere

What it usually means

Test at the outside vent before any part is discussed

A salted-shut backdraft damper is the local cause nobody looks for

The manuals carry no troubleshooting section at all — three checked

What to do in the next ten minutes

Turn the hood to full and go outside to the vent. Hold a tissue near it: if nothing moves, nothing inside the hood is the problem. Then take the grease filters out, wash them in the dishwasher, and look at the impeller behind them — a fan loaded with grease moves a fraction of the air it should and sounds perfectly normal doing it.

Why there is nothing to look up

The CG1, CO4927S and CBB901SB manuals were read in full and not one of them has a troubleshooting section — not a thin one, not a symptom table, none. So everything on this page comes from what actually fails on a hood rather than from a document, and we would rather say that plainly than imply a source that does not exist.

The damper nobody checks

Where the duct leaves the building there is usually a backdraft damper, a light flap that opens under airflow and closes against wind and rain. On a coast it corrodes, and a damper that has stopped opening ends extraction completely while the hood carries on sounding exactly as it always did. It is minutes to free while it still moves and a part once it does not.

### It has got much louder as well.

Noise that grew over months is grease on the impeller and recovers with a proper clean. Noise that arrived suddenly is a bearing or something loose, and that one is worth stopping the hood for.

### Can a recirculating hood be ducted outside?

Frequently, and on this coast it is worth asking about, since a recirculating liner hands heat and moisture back to a kitchen with a surplus of both. Whether it can be done depends on the run above the cabinets and on the building.

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