Smoke is not clearing and the line is hot

Smoke that hangs over the cook line with the hood running means the exhaust system is not doing its job. It is one of the more urgent exhaust problems, because it generally means something is genuinely wrong rather than dirty.

Run through these before calling anyone

1. Is the fan actually running, and does it sound right? Go up, or send somebody up, and listen. A fan that is on but slow, noisy, or vibrating has a mechanical problem: a slipping or broken belt, worn bearings, or a wheel loaded with enough grease to throw it out of balance. A belt is inexpensive; a seized bearing is not, and running it that way is how a cheap repair becomes a motor.

2. Look at the filters. Loaded filters choke the system. So do the wrong filters: mesh instead of baffle, gaps at the edges, or a missing filter with the gap left open. Filters are the cheapest part of this entire system to get right.

3. Open a door. If an exterior door is hard to pull open, or slams when it releases, the kitchen is under negative pressure and you have a make-up air problem, not an exhaust problem.

4. Watch a pilot light or a burner flame. Pulled sideways or blowing out is the same diagnosis.

5. Ask when the duct was last cleaned to bare metal. A duct restricted by years of accumulation cannot pass its design airflow. This one is invisible and it is common.

Make-up air, which is the one people miss

Every cubic foot the exhaust fan removes has to be replaced. In a properly built commercial kitchen, a make-up air unit supplies it deliberately.

When that unit is switched off, undersized for the exhaust, or has blocked filters, the kitchen goes negative. The exhaust fan is then trying to pull air out of a sealed box: it cannot move its rated volume however healthy it is, and smoke stays on the line.

Kitchens can spend real money on the exhaust side, twice, for a problem that was on the supply side the whole time. If doors are hard to open, start here.

Why this becomes an inspection problem

A system that is not performing is a system generating findings. Grease-laden vapour going into the kitchen instead of up the duct settles on ceilings, walls, and equipment, and an inspector will notice that before you do. It also usually means the duct is loaded, which is the actual fire load. The failed fire inspection page covers what happens next.

What it costs

From the pricing page, and the cost calculator prices your kitchen.

Get it looked at soon

Tell us how many hoods you run, what you cook, when the system was last cleaned to bare metal, and whether doors are hard to open with the hood on. That last answer changes the diagnosis completely, so it is worth checking before you call. We schedule the work after close so the kitchen is not down. The service area is Fargo, West Fargo, Horace, Casselton, and Grand Forks.