Canopy, filters & fan
The extract fan is the hardest-working and most-forgotten part of the system. Grease builds on its blades and housing until the fan is unbalanced, derated and running hot - and because it fails gradually rather than suddenly, most kitchens do not notice until extraction has collapsed or the fan has burned out.
The short answer
The extract fan is the hardest-working and most-forgotten part of the system. Grease builds on its blades and housing until the fan is unbalanced, derated and running hot - and because it fails gradually rather than suddenly, most kitchens do not notice until extraction has collapsed or the fan has burned out.
The detail
The extract fan sits at the end of the grease path, pulling grease-laden air through the whole system, so everything the filters and duct did not catch ends up on its blades and in its housing. Because it is often on a roof or hidden in a plant space, it is the component least likely to be looked at - which is exactly why it is usually the dirtiest part of a neglected system.
Grease on a fan does specific damage. It builds unevenly on the blades, so a wheel that was balanced now runs with a wobble that stresses the bearings and shaft. It adds weight and roughness that cut the volume of air the fan can move, so extraction at the cooktop falls even though the motor is working harder. And it insulates the motor, so the whole assembly runs hotter than it was designed to.
The failure is quiet because it is gradual. There is rarely a dramatic moment - just a kitchen that has slowly grown hotter and smokier, a fan that has started to hum or vibrate, and an energy bill that has crept up as the motor labours. By the time someone investigates, the bearings may be worn, the wheel corroded, or the motor close to burning out from years of running hot and unbalanced.
There is a fire dimension too. The fan and its housing hold grease in the hottest, most electrically active part of the system, and a grease-laden fan is both a fire risk in itself and the last chance to catch grease before it reaches the discharge. TR19 Grease includes the fan and discharge duct in its cleaning and verification scope for exactly this reason.
What it means for you
Cleaning the fan is a job of its own, not something a duct clean sweeps up in passing. The fan must be electrically isolated and, depending on type, partly dismantled to reach the wheel and housing - which is why fan access and isolation should be planned into any system clean rather than left as an afterthought when the panel will not come off.
A properly cleaned fan is a transformed one. With grease off the blades the wheel runs balanced again, so the bearings stop being hammered and the vibration and noise settle. The fan moves its rated volume of air, so extraction at the cooktop recovers, and the motor runs cooler and draws less power. Much of what looked like a failing fan is often just a filthy one.
Regular fan cleaning also protects the biggest single component cost in the system. A fan run dirty for years wears its bearings, corrodes its wheel and cooks its motor, and replacing the assembly is far dearer than cleaning it would have been. Bringing the fan into the routine turns a quiet, expensive failure into a predictable, cheap piece of maintenance.
The service behind the guide
Sibling guides
Roof fan vs in-line fan · Canopy vs full extraction cleaning · Preparing for a visit
Questions
It sits at the end of the grease path and pulls everything the filters and duct missed onto its blades and housing. Being on a roof or in a plant space, it is also the least-inspected part of the system.
It builds unevenly on the blades, unbalancing the wheel and stressing the bearings; it cuts the air the fan can move so extraction falls; and it insulates the motor so it runs hot. The fan slowly derates and can burn out.
Because it is gradual. The kitchen grows slowly hotter and smokier, the fan hums or vibrates, and the energy bill creeps up. By the time it is investigated the bearings or motor may be near failure.
The fan is electrically isolated and, depending on type, partly dismantled to reach the wheel and housing. Access and isolation should be planned into the system clean rather than left as an afterthought.
Yes. The fan holds grease in the hottest, most electrically active part of the system, making it both a fire risk and the last chance to catch grease before discharge. TR19 Grease includes it in cleaning scope.
Phoenix Duct Clean · by the numbers
We clean the whole path - canopy, filters, plenum, ductwork and fan - and verify the result to TR19 Grease. Call or email for a clear quote and a certificate you can show your insurer.