1. Visible grease build-up on filters or ductwork
A small amount of grease on baffle filters is normal — that's their job. But if grease is visibly pooling, dripping, or building up on surfaces beyond the filter housing, your extraction isn't capturing everything it should, and the fire risk starts to climb.
2. Persistent cooking smells beyond the kitchen
If odours are drifting into dining areas, neighbouring units, or the street outside, your filtration and extraction rate may no longer be matched to your cooking load — particularly relevant for restaurants sharing premises with other businesses or residential neighbours.
3. Unusually loud or vibrating fans
Extraction fans should run consistently. A sudden increase in noise, rattling, or vibration transmitted through ductwork or the canopy itself often points to worn bearings, an unbalanced fan, or ductwork that's come loose — all worth investigating before they fail completely, usually at the worst possible time.
4. A hot, stuffy kitchen despite the extraction running
If staff are still working in oppressive heat with the extraction system switched on, the make-up air balance may be wrong. Every extract system needs to be balanced by an input or make-up air system — without it, the extraction fights against negative pressure and struggles to actually clear the air.
5. It's been longer than 12 months since your last inspection
Regulations and insurance requirements aside, an annual inspection of your extraction canopy, ductwork and gas interlock system catches small issues — a worn seal, a failing sensor, a partially blocked filter — before they become an expensive breakdown or, worse, a compliance failure during an Environmental Health inspection.
What to do next
If any of the above sounds familiar, it's worth booking a proper inspection rather than waiting for a visible failure. Cool Stream Ventilation's service and maintenance programmes are tailored to your equipment, environment and budget — covering everything from filter replacement to full system overhauls.
