The short answer
A commercial cabinet drifting warm is usually failing to reject heat: a grease-bound condenser, a blocked air path, or a kitchen that has got hotter than the cabinet is rated for. A knocked-about door gasket is the next candidate. Move the stock first, then check those. Anything left after a clean condenser and a good gasket is a service call, and an urgent one.
What you observe
- The cabinet runs continuously and still reads warm — It cannot reject heat, or cannot keep cold in.
- Temperature is fine overnight and poor during service — Door traffic and kitchen heat, not a failed part.
- A grey mat of grease and dust across the condenser — The commonest commercial cause, and visible.
- A gasket that is torn, flattened or no longer grips — Trays and trolleys wreck commercial door seals.
- NEAR MISS — the cabinet is silent and dark — That is a supply or control fault, not cooling.
Causes, most likely first on this class
- Condenser bound with grease and dust — First in a commercial kitchen because airborne grease turns dust into a mat that resists both airflow and a casual wipe. The cabinet then runs continuously and still falls behind.
- Door gasket damaged or no longer sealing — Second: a commercial door is opened constantly and its gasket is caught by trays and trolleys, so it fails years earlier than a domestic one.
- Air path blocked by stock or an overloaded cabinet — Third, and common at peak: boxes packed against the return vents stop air circulating, so part of the cabinet is cold and part is not.
- Ambient too high, or a sealed-system fault — Last. A kitchen that has grown hotter pushes the cabinet outside its rating, and a genuine refrigeration fault is the remaining case once everything above is clean.
Check in this order, and why
- Move the stock to a cabinet you trust — Not a diagnostic step. Do it before anything else.
- Look at the condenser for a grease mat — Top cause, visible in seconds, correctable on site.
- Run a hand round the door gasket with the door shut — Cold escaping at a point is a torn or flattened seal.
- Clear stock away from the return vents — Left until here, but it explains uneven cabinet temperature.
What an owner can safely check
- Move perishable stock to a working cabinet — Record the time and temperature if you keep a log.
Tools: thermometerAbout 30 min
- Isolate the cabinet and degrease the condenser — Work with the fins. Let it dry fully before restarting.
Tools: degreaser, vacuum, soft brushAbout 40 min
- Test the gasket with paper all the way round — Where it slides free, warm air is getting in continuously.
Tools: sheet of paperAbout 15 min
- Unload and repack, keeping the vents clear — Leave the return and supply grilles unobstructed.
About 30 min
- STOP HERE if the cabinet stays warm after all of that — Sealed-system and control work needs a technician.
Before you open anything
Safety
Isolate the cabinet at its switch or breaker before touching the condenser or any panel; a capacitor can hold a charge after the power is off. Condenser fins are sharp and the fan can start without warning while the unit is live. Never chip ice off an evaporator with a tool, and never cut or lever a refrigerant line. Do not move a loaded cabinet on castors alone. Treat any stock above safe temperature as a food-safety decision, not a repair one.
When to call a technician
Call as soon as the condenser is clean, the gasket seals, the vents are clear and the cabinet still cannot hold temperature — you are then into the sealed system or the controls, and every hour costs stock. Call immediately if you see oil around the compressor, smell burning, or the cabinet has iced over solid. In a commercial setting, treat this as an urgent call rather than a scheduled one.
Nearest pages of this class
What this page does not cover
This page is written for the brand and the appliance class, not for one family or model line. Where a family- or model-specific page exists for your unit, that page is the more specific answer and you should start there. Deliberately absent: climate-class ratings, setpoint and pull-down figures, gasket and control part identifiers and refrigerant charges, all of which differ between the upright, under-counter and prep-counter families.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
