Service
Commercial Kitchen Make-Up Air Fan Repair
Make-up air replaces the air your canopy extracts. When the supply fan fails, the kitchen goes into depression — doors pull shut, appliances flue badly, extract volume collapses and the gas interlock starts tripping.
- Supply fan, damper, inverter and control repairs
- Extract and make-up air rebalanced and documented
- Interlocked so gas cannot run without both fans proven
Symptoms of a make-up air failure
- Gas interlock trips when extraction runs at full speed
- Kitchen doors hard to open or whistling around the frames
- Smoke and steam rolling out of the canopy instead of being drawn up
- Appliance pilots blowing out or flames lifting
- Very hot kitchen with a fan that sounds like it is running
- CO or CO₂ alarms activating in the kitchen
What we repair
- Supply fan motors, bearings, belts and impellers
- Inverters, contactors, overloads and control wiring
- Motorised dampers, actuators and end switches
- Frost coils, filters and intake grilles
- Interlock wiring so both extract and supply are proven before gas is released
- Rebalancing extract to supply so the kitchen sits slightly negative, not starved
If you can smell gas
- Turn off the gas at the emergency control valve and press the emergency stop button
- Do not switch anything electrical on or off, and do not use naked flames
- Open doors and windows, evacuate and keep people clear
- Call the National Gas Emergency Service on 0800 111 999
- Only then call us to make the installation safe and return it to service
Frequently asked questions
Does make-up air have to be interlocked?
Where mechanical make-up air is fitted, the interlock should prove it along with extraction — otherwise the kitchen can cook while heavily depressurised, which is exactly what BS 6173 sets out to prevent.
Why does my gas trip only at busy times?
Because at full extract with no make-up air the kitchen depressurises and extract volume falls below the proving set point. Fixing the supply side usually cures the trips for good.
Can you survey the airflow?
Yes, we measure extract and supply volumes and report against the canopy requirement, then correct the balance.
Do you fit new make-up air fans?
Yes, including replacement supply fans, controls and interlocking.
Related guides
Gas Shuts Off When Extraction Starts
Pressure switch set wrong, ducting or make-up air imbalance.
Interlock Fan Fault
Fan fail lamps, airflow switch faults and extract failures.
Air Pressure Switch Repair
Differential switch setting, tube blockage and replacement.
Commercial Kitchen Gas Safety
Ventilation interlock, airflow proving and CP42 compliance.
Sensors & Controls
Air pressure switches, airflow sensors, current monitors, e-stops.
Gas Interlock Systems
The pillar guide: how interlocks work, standards and fault-finding.
Parts in stock — ready to fit
Held in UK stock and carried on our vans, so most jobs are fixed in one visit.
Replacement gas interlock systems
Merlin, Medem, Intelligas, S&S Northern
In stock today
Air pressure switches
Fan & gas proving pressure switches
In stock today
Gas solenoid valves
Normally closed safety shut-off valves
In stock today
Quick release gas catering hoses
Commercial ranges, bays & mobile catering
In stock today
Super universal thermocouples
Fits most commercial gas appliances
In stock today
Need a part fitted?
Same-day engineer dispatch with these parts on the van.
Gas Safe Registered
Commercial catering & plant
24/7 UK Response
Same-day emergency dispatch
Vetted Engineers
DBS checked for schools & care
Transparent Pricing
Fixed callout, quoted parts