What the interlock does
Gas appliances under a canopy rely on the extraction to remove fumes and combustion products. The gas interlock watches the extraction, usually with an airflow (pressure) switch or by monitoring the fan’s current. If it can’t see enough airflow, it closes a valve and cuts the gas to the cooking line.
That’s why a failed fan stops the whole kitchen. It’s a safety system doing its job, and most interlocks need a manual reset once the cause has been fixed.
Never bypass or wedge the interlock. Overrides aren’t allowed, and cooking without extraction can quickly build up carbon monoxide and carbon dioxide in the kitchen.
Common reasons it keeps tripping
- The fan has stopped, or is running too slowly to prove airflow.
- A failing motor or capacitor that runs some days and not others.
- A speed controller turned down too low for the airflow switch.
- Blocked canopy filters or ductwork reducing airflow.
- A faulty airflow switch, sensor or tube on the interlock itself.
What we do
We check the fan first, because that’s where the fault is in most cases. If the fan needs replacing, we fit and set it up so it proves reliably and the interlock can be reset. If the problem is in the interlock panel itself, we’ll tell you and can put you in touch with a Gas Safe registered engineer.