If your commercial fridge is not cooling, five checks are safe for staff: power, setpoint, the door and its seal, stock blocking the air vents, and the condenser grille. Anything involving refrigerant, the compressor or internal wiring belongs to an F-Gas certified engineer.
You open the undercounter at half past six and last night's prep feels wrong. The display says 9°C, the compressor hums as if nothing has happened, and service starts at noon. Every question that matters is about the next four hours, not the next four weeks, because the food has a clock on it and the fridge does not.
This post covers plug-in cabinets: upright reach-ins, undercounters, prep counters, glass-door display fridges and back-bar bottle coolers. If the problem is a walk-in room, our cold room diagnostic sequence is the right read. If the cabinet is cold enough but keeps building ice, that is a different fault, covered in our post on why a commercial freezer ices up.
At a glance
| Question | Answer |
|---|---|
| Legal maximum for chilled food in England | 8°C at food premises; keeping high-risk food above it "commits an offence" |
| FSA working target for a fridge | 0°C to 5°C |
| Service or display tolerance | Above 8°C for less than four hours, once only |
| Safe staff checks | Power, setpoint, door and seal, loading and air paths, condenser grille |
| Engineer only | Refrigerant, compressor and internal electrics; refrigerant work needs an F-Gas certified engineer |
| First move when a cabinet warms | Protect the stock, log the time and temperature, then diagnose |
Source: The Food Safety and Hygiene (England) Regulations 2013, Schedule 4 and How to chill, freeze and defrost food safely, GOV.UK
Protect the food before you touch the fridge
In England the legal line is 8°C. Schedule 4 of the Food Safety and Hygiene (England) Regulations 2013 makes it an offence to keep food that is "likely to support the growth of pathogenic micro-organisms or the formation of toxins" at or in food premises "at a temperature above 8°C". The FSA's working target is tighter: "Your fridge should be set between 0 and 5°C", because the legal 8°C is a ceiling, not a setpoint. A cabinet holding at 7.5°C is legal and still wrong.
So the first job is the stock, not the machine. Move high-risk food, meaning cooked dishes, dairy, prepared salads and anything with a use-by date, into a working cabinet or the cold room, and take the temperature of the food itself rather than trusting the display. The regulations quietly expect breakdowns: Schedule 4 gives a defence where food rises above 8°C for an unavoidable reason, including "temporary breakdown of equipment", provided it is for a limited period and consistent with food safety. What "limited" means gets decided by your records. Write down times and readings from the moment you notice. The full procedure for that judgement is in our guide to UK food storage temperature rules.
The legal temperature rules for chilled food
The rules kitchen managers half-remember, set out properly, as of October 2026.
| Situation | The rule | Where it comes from |
|---|---|---|
| Chilled holding at food premises | 8°C maximum for food that supports the growth of pathogens or formation of toxins | Schedule 4, paragraph 2 |
| Food out for service or on display for sale | May be above 8°C once, "for a period of less than four hours" | Schedule 4, paragraph 5 |
| Breakdowns, defrosting, moving stock | Defence where food is warmer for an unavoidable reason, "for a limited period only", consistent with food safety | Schedule 4, paragraph 5 |
| Mail order | The 8°C rule does not apply while food is being conveyed to the final consumer | Schedule 4, paragraph 2(2) |
| Stored above 8°C by design | Lawful where the manufacturer recommends it for a stated shelf life, backed by a "well-founded scientific assessment" | Schedule 4, paragraph 4 |
| Hot holding | 63°C minimum where heat is controlling bacteria | Schedule 4, paragraph 6 |
| Working fridge target | "Your fridge should be set between 0 and 5°C"; the zone between 8 and 63°C is "the Danger Zone" | FSA chilling guidance |
Source: The Food Safety and Hygiene (England) Regulations 2013, Schedule 4 and How to chill, freeze and defrost food safely, GOV.UK
This is the regulation as written, not advice on your case; your local authority's environmental health team is the right call for anything borderline.
Two patterns: running but not cold, or not running at all
Every "commercial refrigerator not cooling" call is one of two machines, and telling them apart early saves time.
The first is a fridge that is not running at all. No lights and no hum usually means no power, and the supply is an often overlooked cause of a dead cabinet. Plugs get pulled for floor polishers, sockets get switched off at the wall, breakers trip overnight and get reset without anyone asking why. Check the socket with a phone charger and the breaker board before you mourn the compressor. Lights on but silence is different: the lighting in a display fridge often runs separately from the refrigeration side, so a cabinet can look alive while the refrigeration side is dead. Listen for a click every few minutes followed by nothing. That is the compressor trying to start and failing, which usually points at the start relay or overload, or the compressor itself.
The second pattern is a fridge running but not cold, and it is the sneakier one because everything sounds healthy. The compressor hums, the fans spin, and the temperature climbs anyway. Common causes include a condenser choked with dust and kitchen grease, a failed condenser fan, an evaporator coil iced solid enough to choke the airflow, a failed evaporator fan (the classic sign is a cabinet cold at the bottom and warm at the top), low refrigerant from a leak, or a compressor wearing out.
Symptoms, common causes and who does what
Same information, laid out for the wall of the kitchen office. The causes are common ones for plug-in cabinets; the right-hand column is where the line sits between staff and an engineer.
| Symptom | Common causes | Safe staff check | Engineer job |
|---|---|---|---|
| Dead: no lights, no sound | Unplugged, socket switched off, tripped breaker, failed controller | Try another appliance in the socket; check the breaker board | Internal wiring, controller, compressor start gear |
| Lights on, compressor silent, clicking every few minutes | Failed start relay or overload, seized compressor | Confirm the setpoint has not been knocked up; note the click pattern | Start components or compressor |
| Runs constantly, cabinet warm, sides hot | Condenser choked with dust and grease, failed condenser fan | Look at the grille for a grey mat of fluff; feel for warm air moving | Deep condenser clean, condenser fan motor |
| Runs constantly, cools a bit, never reaches setpoint | Worn door seal, stock blocking air vents, low refrigerant | Paper test on the seal; check stock is clear of the vents | Evaporator fan, leak find and repair, regassing |
| Cold at the bottom, warm at the top | Failed evaporator fan, iced coil blocking airflow | Listen for the internal fan with the door switch pressed | Fan motor, defrost system |
| Fine overnight, loses temperature through lunch | Room too hot, condenser recirculating its own air, sun on a glass door | Room temperature at the cabinet; direct sun through the window | Siting and ventilation changes |
The split between staff and engineer reflects the F-Gas qualification rules, GOV.UK for refrigerant work and regulation 14, Electricity at Work Regulations 1989 for live electrics.
The seal check deserves ten seconds of explanation. Close the door on a strip of paper and pull; resistance all the way round means the gasket still works, a section that slides free is your leak path. Seals are a cheap fix, and our guide to replacing a door gasket covers it properly.
The condenser: the cheapest fault in the building
The condenser is the grille, usually at the bottom or back of the cabinet, where all the heat pulled out of your food is dumped into the room. In a kitchen it spends its days hoovering up dust, flour and airborne grease until the fins mat over. The compressor then runs longer and hotter to shift the same heat, and the cabinet loses ground mid-afternoon, with the ovens on and the extraction working against it.
The annoying part is how preventable it is. Clean it at the interval the cabinet's manual sets, and more often near fryers: isolate the power, brush the grille with a soft brush and vacuum it through. Go with the fins, not across them, because they bend. That is the whole job, and it costs nothing. Our post on how often commercial fridges should be serviced sets it inside a proper schedule.
While you are down there, look at where the cabinet lives. A unit pushed hard against a wall or boxed into joinery recirculates its own hot air and runs in a room far hotter than the one you are standing in. Commercial cabinets are designed for a stated maximum room temperature, given in the manual or on the rating plate, and a kitchen that runs hotter than that is working against the cabinet all day. Glass-door display fridges and bottle coolers cop it twice over, because the door openings are constant and a sunny window turns the cabinet into a greenhouse. A display fridge not cooling in July, in a shop with south-facing glass, is often just physics winning.
What needs an F-Gas certified engineer
The line between staff and engineer is not politeness, it is law. GOV.UK is blunt: "You must have your own qualifications to work on equipment containing F gas, even if you work for someone else", and "It is against the law to work with F gas if you do not have the correct qualifications" (Qualifications to work with F gas, GOV.UK). The covered work includes installing, servicing and maintaining systems, checking for leaks, recovering gas and decommissioning. A friendly handyman with a refrigerant cylinder is not a grey area.
If low refrigerant turns out to be the cause, the rules get stricter, not looser. A leak is repaired, not topped up: "repair it as soon as possible and repeat the test within a month to check the repair worked" (Checking F gas equipment for leaks, GOV.UK). A regas without a leak repair is paying twice for the same fault. One more thing: some cabinets run on propane (R290) or isobutane (R600a), which are flammable refrigerants rather than F gases. The F gas qualification rules do not cover them, but a flammable refrigerant circuit is no place for improvisation either. The same goes for the electrics: regulation 14 of the Electricity at Work Regulations 1989 restricts work "on or so near any live conductor" where danger may arise, and a duty manager with a multimeter does not meet the exceptions.
When to call an engineer
Call when the safe checks change nothing, when the compressor clicks and never starts, when the cabinet runs constantly and still climbs, or when the same unit has been "a bit warm" three times in a quarter. We are a family-run London firm, trading since 2004, with F-Gas certified engineers and more than 2,000 projects across London and the South East, and we take emergency calls around the clock. If you need a commercial fridge repaired, ring us and we will agree a realistic arrival window on the phone.
Frequently asked questions
Why is my commercial fridge running but not cold?
Often heat rejection or airflow rather than gas. A condenser choked with dust and grease, a failed fan, or an iced evaporator will leave a cabinet sounding perfectly healthy while the temperature climbs. Work through the safe checks in the table above before assuming a refrigerant problem.
What temperature should a commercial fridge be?
Set it between 0 and 5°C, per the FSA's guidance. The legal ceiling in England is 8°C for food that supports bacterial growth, but that is the point where an offence begins, not a target.
How long is food safe in a fridge that has stopped cooling?
The law gives a defence for an unavoidable breakdown lasting "a limited period", and the service or display tolerance is less than four hours above 8°C, once only. Judge the food by its own temperature, move high-risk stock to a working cabinet quickly, and log everything. When in doubt, your local authority's environmental health team decides, not a blog post.
Why is my display fridge or bottle cooler not cooling?
The same causes as any cabinet, amplified. Glass doors mean constant opening, condensers under the counter clog fast, and direct sun through a shop window adds a heat load the cabinet was never sized for. Check the grille and the sun before anything else.
Can I top up the refrigerant in a commercial fridge myself?
No. Working on equipment containing F gas without the correct personal qualification is against the law in the UK, and a top-up without finding the leak breaks the rules and fixes nothing. Some cabinets run on flammable refrigerants, which brings its own hazards. This one is an engineer's job, full stop.
A warm cabinet is a clock, not a crisis
Plenty of warm cabinets turn out to be boring: a tripped breaker, a blocked grille, a door seal that gave up months ago. Boring is good, because boring is cheap. Protect the stock first, work the safe checks in order, and you will either fix it before lunch or hand an engineer a diagnosis that halves the visit. And if the fault turns out to be a tired compressor on an elderly cabinet, the next question is whether to spend on it at all, which is exactly what our post on the repair versus replace decision is for.
About the author: Ali Elm runs Be Cool Refrigeration & Air Conditioning, a family-run London firm that has been installing, servicing and repairing commercial refrigeration and air conditioning since 2004. His F-Gas certified team has delivered more than 2,000 projects across London and the South East.
Last updated: 14 October 2026
Written by
Ali Elm
Ali is the Head of Operations at Be Cool Refrigeration with over a decade of hands-on experience in HVAC and commercial refrigeration. He oversees every installation, repair, and maintenance project, making sure the work meets the highest standards. Ali holds full F-Gas certification and has worked across residential, commercial, and industrial refrigeration systems throughout London and the South East. When he is not on site, he writes these guides to help business owners and homeowners understand their cooling systems better.