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The post Commercial Fridge not cooling? first appeared on ADK Kooling.

Supermarket refrigeration isn’t like a domestic fridge. These are complex multi-case systems running off central compressor racks, with individual solenoid valves, expansion valves, and evaporators for each display case. When one case runs warm, the cause could be local to that specific case or systemic across the entire rack. Here’s how to work through it methodically.

Faults like this are common across commercial sites in North London. Enrolling in a emergency breakdown service schedule helps catch the warning signs early, reducing the chance you will ever need an refrigeration installation.

Iced-Up Evaporator — Defrost Failure

The most common cause of a single case running warm. Every refrigeration display case runs scheduled defrost cycles — typically electric heater defrosts — to clear frost from the evaporator coil. If the defrost heater element fails, the defrost timer malfunctions, or the termination thermostat is faulty, ice accumulates on the evaporator with every cooling cycle until airflow is completely blocked.

You can often identify this without opening the case panels. If the air curtain across the front of the case feels weak or non-existent, the case temperature is rising steadily, and there’s visible frost on the back panel or around the air discharge grille, you’re almost certainly looking at a defrost failure. The evaporator needs a manual defrost to clear the ice — which takes time and means the case is out of service — followed by diagnosis and repair of whichever defrost component has failed.

Failed Solenoid Valve on the Liquid Line

Each display case on a centralised rack system has a liquid line solenoid valve. When the case thermostat calls for cooling, this solenoid opens and allows liquid refrigerant to flow to the case’s expansion valve and into the evaporator. If the solenoid fails in the closed position, no refrigerant reaches that case. The evaporator warms to ambient temperature, the case temperature climbs, and everything else on the rack continues operating normally — because the fault is isolated to that one valve.

Diagnosis is straightforward. Check for voltage at the solenoid coil when the case thermostat is calling for cooling. Voltage present but the valve not opening means the coil or the valve mechanism has failed. Listen for the click when the solenoid should energise. No click with voltage present confirms a dead coil. Solenoid coils are one of the most common spares a refrigeration engineer carries.

Blocked Expansion Valve

The thermostatic expansion valve (TXV) meters liquid refrigerant into the evaporator at precisely the rate needed for efficient heat exchange. These valves have small internal orifices that can block with wax from oil breakdown, moisture that’s frozen into ice crystals, or metallic debris from compressor wear circulating through the system.

A partially blocked TXV starves the evaporator — the case cools, but not enough to maintain safe temperatures under load. A fully blocked TXV means zero cooling. Wax blockages typically indicate degraded compressor oil in an aging system. Moisture blockages point to a failed or saturated filter drier on the liquid line. The TXV itself can be replaced, but the contamination source needs addressing — otherwise the replacement valve will block in the same way.

Evaporator Fan Failure

The evaporator fans serve two critical functions: they circulate cold air through the case to keep product at temperature, and they maintain the air curtain across the front of the case that prevents warm store air from entering. If a fan motor fails, airflow drops. Cold air pools at the bottom of the case, warm air infiltrates from the top, and the temperature sensor — usually positioned in the return air path — reads high.

Listen to the case. If it’s quieter than the identical cases either side of it, check the fans. Most display cases have multiple small fan motors, and losing one might not be immediately obvious visually. But the temperature impact is measurable within hours. Fan motors on display cases are a standard replacement item and can usually be swapped without recovering refrigerant.

Product Loaded Past the Air Curtain Line

Every open-front refrigerated display case has a load line — a marked position or shelf height that represents the maximum product level. Products stacked above this line physically break through the air curtain. Warm store air flows directly into the case, the evaporator can’t cope with the extra heat load, and the temperature climbs. The refrigeration system is working perfectly — the case is just being asked to do more than it was designed for.

This is an operational problem, not a mechanical one. Staff stacking shelves need to understand that overfilling a case above the load line doesn’t increase sales — it warms the product and creates a food safety risk. Check the load line before calling an engineer. It might save you a call-out charge.

Night Blinds Not Being Deployed

Open display cases are engineered to operate with night blinds — covers pulled down or across the case front when the store is closed. These blinds reduce the refrigeration load dramatically by eliminating warm air infiltration when product visibility is unnecessary. If closing staff aren’t deploying night blinds, the cases work substantially harder overnight. Compressors run longer, energy consumption spikes, and the entire system operates under stress it was never designed for.

Businesses running Bitzer equipment can call our dedicated team for same-day diagnosis. We have also written a detailed guide on cold room evaporator icing up which covers a closely related failure mode worth checking.

The cumulative effect of not using night blinds accelerates compressor wear, increases the risk of mechanical failure, and inflates energy bills. Making night blind deployment part of the closing checklist is a management discipline issue with direct mechanical and financial consequences.

Compressor Failure on the Rack System

If multiple cases are running warm simultaneously, the problem is almost certainly upstream at the compressor rack rather than in any individual case. A failed compressor reduces the rack’s total cooling capacity. The remaining compressors might handle the load during quiet periods, but during peak trading hours — with heavy customer traffic, frequent case door openings, and high ambient temperatures in the store — they can’t keep up. Suction pressure rises, evaporator temperatures climb, and case temperatures follow.

Check the compressor rack. Are all compressors running? Is one tripped on overload or locked out with an error? Rack compressor failures need urgent attention because they affect multiple cases across multiple product categories simultaneously. One failed compressor can put thousands of pounds worth of chilled stock at risk.

Food Safety Compliance

UK food safety regulations require continuous temperature monitoring of chilled display equipment and documented corrective actions when temperatures breach safe limits. If your chilled case is above 8°C, you should already be following your HACCP procedures: recording the breach, pulling affected product, documenting what corrective action was taken, and retaining records for inspection. Environmental health officers check these records, and gaps in your temperature logs raise immediate red flags.

ADK provides emergency refrigeration repair for supermarkets and food retail across London. We understand the urgency — a warm display case isn’t just a repair ticket, it’s a food safety incident with compliance implications. Call us on 0207 801 0808 and we’ll get an engineer to you fast.

The post Supermarket Refrigeration Case Running Warm — What to Check first appeared on ADK Kooling.

Every cold room evaporator accumulates frost during normal operation. That’s physics — warm, moist air meets a sub-zero coil and moisture freezes on the surface. But a properly functioning system has a defrost cycle that melts this frost periodically, keeping the coil clear. When that defrost cycle fails, ice builds up fast and the consequences cascade quickly.

Faults like this are common across commercial sites in East London. Enrolling in a emergency breakdown service schedule helps catch the warning signs early, reducing the chance you will ever need an PPM.

How the Defrost Cycle Works

Before we get into fault causes, it’s worth understanding how defrost works. Most commercial cold room evaporators use electric defrost heaters — resistive elements embedded in or strapped to the coil. A timer or controller initiates defrost at set intervals (typically two to four times per day), the compressor stops, and the heaters switch on to melt accumulated frost. The meltwater drains into a tray and out through a heated drain line to a collection point outside the cold room.

A defrost termination thermostat monitors the coil temperature. Once the coil reaches a set point — usually around 10°C to 15°C — the thermostat signals that defrost is complete, the heaters switch off, and the compressor restarts. The whole cycle takes 15 to 30 minutes. When any part of this sequence fails, ice accumulates with every operating cycle.

Failed Defrost Timer or Controller

This is the most common cause of evaporator icing. The defrost timer — whether a mechanical clock timer or an electronic controller — is responsible for initiating the defrost cycle. If it fails, defrost never starts. Frost builds from the first hour of operation and gets worse by the day.

Mechanical timers are notorious for sticking. The motor that drives the timer cam can fail, or the contacts can burn and weld shut in the wrong position. Electronic controllers can lose their programming after a power cut, or the controller itself can fail. Either way, no initiation signal means no defrost and a steadily growing block of ice on the coil.

Defrost Heater Element Burned Out

Even if the timer initiates defrost perfectly, the heaters have to actually work. Electric defrost heaters operate in a harsh environment — cycling between sub-zero temperatures and high heat, surrounded by moisture. Over time, the elements corrode and burn out. If one or more heater elements have failed, the defrost cycle runs but doesn’t generate enough heat to melt the frost completely.

You’ll often see a pattern: the part of the coil closest to a working heater is clear, while the rest is iced. A resistance check on each heater element quickly identifies which ones have failed. Replacement heaters are specific to the evaporator model but are generally a straightforward swap.

Defrost Termination Thermostat Failed

The termination thermostat tells the system when defrost is complete. If it fails closed (always satisfied), the defrost cycle terminates immediately after starting — the controller thinks the coil is already warm when it isn’t. The heaters run for seconds instead of minutes, nowhere near long enough to clear the frost.

If it fails open (never satisfied), the defrost runs for the maximum time but that’s less of an icing problem and more of an energy and temperature-control issue. The failed-closed scenario is the one that causes rapid ice build-up. Testing the thermostat with a multimeter at ambient temperature versus coil temperature confirms whether it’s switching correctly.

Low Refrigerant Charge

A refrigerant leak causes the evaporator to operate at a lower pressure and temperature than designed. The coil surface drops well below zero — potentially to -25°C or colder — which means frost forms faster and denser than the defrost cycle can cope with. Even a fully functional defrost system can’t keep up if the coil is running 10 degrees below its design temperature.

Signs of low refrigerant alongside icing include: the compressor running continuously, the cold room struggling to pull down to temperature between defrost cycles, and frost or ice forming unevenly on the coil (concentrated at the inlet). A pressure check confirms the charge level, and the leak needs to be found and repaired before recharging.

Damaged Door Gasket

A torn, compressed, or missing door gasket allows warm, moisture-laden air from the kitchen to constantly infiltrate the cold room. That moisture has to go somewhere — and it ends up as frost on the coldest surface in the room, which is the evaporator coil. The defrost system may be working correctly but simply cannot keep up with the volume of moisture entering through the bad seal.

This problem often goes hand in hand with a cold room compressor running constantly. If you are noticing both symptoms, it is worth getting an engineer out before the system fails completely. We have also covered walk-in freezers not holding temperature in a separate guide.

Close the cold room door and look for daylight around the edges. Feel for cold air escaping. If the gasket is damaged, replacing it is cheap and quick — and it solves the moisture problem at source rather than trying to defrost it away after the fact.

Evaporator Fan Not Running

The evaporator fan circulates cold air around the room and across the coil. If the fan motor fails, air stagnates around the coil surface. Without airflow, moisture in the immediate vicinity of the coil freezes and stays frozen. Ice builds from the coil outward in a dense, solid mass rather than the light frost you’d normally see.

A failed evaporator fan also means the room warms unevenly — the area near the coil may stay cold while the far end climbs in temperature. Listen for the fan when the compressor is running. If the cold room is quiet, the fan has likely failed and needs replacing.

Emergency Response

A fully iced evaporator is an emergency for any food business. Product temperatures climbing above safe limits means potential stock losses and food safety risk. Step one is to move critical stock to another cold storage if available. Step two is to call an engineer.

ADK provides emergency cold room repair across London. We carry defrost timers, heater elements, termination thermostats, fan motors, and refrigerant for the most common cold room systems. We diagnose the root cause — not just defrost the ice and leave — because if the underlying fault isn’t fixed, the ice will be back within 24 hours. Call us day or night.

The post Cold Room Evaporator Icing Up Badly — What’s Going Wrong first appeared on ADK Kooling.

Glycol cooling systems are straightforward in principle: a chiller cools a glycol-water mix, a pump circulates it through the load, and it comes back warm to be cooled again. When the system can’t maintain temperature, the fault is either in the chiller, the circulation, or the glycol itself.

We handle this type of problem frequently for businesses in Brixton and the surrounding area. If your system is showing these symptoms, our PPM team can usually diagnose the root cause on the first visit.

Low Glycol Level

The first thing to check and the most common cause. Glycol systems lose fluid over time — from small leaks at fittings, pump seals, or hose connections, and occasionally from evaporation in open or poorly sealed reservoir tanks. When the level drops too low, the pump starts drawing air, circulation becomes erratic, and cooling capacity falls off a cliff.

Check the reservoir tank. If the glycol level is below the minimum mark — or below the pump inlet — top it up with the correct glycol-water mix. Don’t just add water. Diluting the glycol concentration changes the freeze point and thermal properties of the entire system. And if the level dropped quickly, find the leak before topping up — otherwise you’ll be doing this again next week.

Incorrect Glycol Concentration

Glycol concentration matters more than most people realise. Too little glycol in the mix and the fluid can freeze inside the chiller’s evaporator when the system pulls down to low temperatures. Too much glycol and the thermal capacity drops — the fluid can’t absorb and carry heat as efficiently, which means the system struggles to cool the load even though the chiller is working hard.

For most beer and beverage applications, propylene glycol concentration should be between 30% and 40% by volume, giving a freeze point well below the operating temperature while maintaining good heat transfer. A refractometer check takes two minutes and tells you exactly where the concentration sits. This should be checked annually at minimum.

Failed Circulation Pump

The chiller can be making ice-cold glycol, but if the circulation pump has failed or is running at reduced capacity, that cold glycol never reaches the load. A pump impeller can wear, a motor winding can partially fail (pump runs but slowly), or the pump can seize entirely.

Check the pump — is it running? Is it vibrating normally? Feel the glycol lines either side of the pump. The supply line should be noticeably colder than the return. If both lines are the same temperature, the glycol isn’t flowing properly. A pump swap is a routine repair that gets the system back online quickly.

Dirty Condenser Coil

The chiller rejects its heat through a condenser coil — either air-cooled or water-cooled. An air-cooled condenser that’s clogged with dust, fluff, or debris can’t reject heat efficiently. The compressor runs hotter, head pressure climbs, and cooling capacity drops. In severe cases, the high-pressure safety switch trips and the compressor shuts down altogether.

Look at the condenser coil. If you can’t see through it, it needs cleaning. In a cellar environment with dust and cardboard fibres in the air, condensers can block up surprisingly fast. A thorough clean with a coil brush and compressed air — working from the clean side out — will often restore full cooling capacity immediately.

Compressor Weak or Failed

If the condenser is clean, the glycol level and concentration are correct, and the pump is circulating, the compressor itself might be the problem. Compressors lose efficiency as they age — valves wear, seals degrade, and the unit can no longer compress refrigerant to the pressures needed for proper heat exchange.

A suction and discharge pressure test will show immediately whether the compressor is pulling its weight. Low discharge pressure and high suction pressure together indicate a weak compressor. At that point, it’s a compressor replacement or a new chiller unit depending on the age and value of the equipment.

If you are also experiencing beer cellar cooling problems, the two faults may share a common cause. Our engineers frequently find that addressing one resolves the other. You might also want to read our guide on cellar coolers freezing up for additional troubleshooting steps.

Glycol Lines Not Insulated

Glycol circulates at temperatures well below the ambient air in a cellar or plant room. If the glycol pipework isn’t insulated — or the insulation has deteriorated — the fluid picks up heat from the surrounding air on its way to the load. On a long pipe run, the heat gain can be significant enough to raise the delivered glycol temperature above what the load requires.

Check the insulation on all glycol lines, particularly in warmer areas like above ceilings, through risers, or past hot water pipes. Any bare copper or steel pipework carrying cold glycol is a heat gain problem and a condensation risk. Proper closed-cell insulation solves both issues.

Blocked Strainer in the Glycol Circuit

Most glycol circuits have a strainer or filter to catch debris. Over time, these block with sediment, pipe scale, or degraded glycol residue — especially in older systems. A blocked strainer restricts flow just like a failed pump would, and the symptoms are identical: the chiller cools the glycol in the tank but it doesn’t reach the load effectively.

Check and clean the strainer. On systems that haven’t been maintained, the strainer can be almost completely blocked. While it’s out, inspect the condition of the glycol itself — if it’s dark brown or smells off, the glycol has degraded and the entire system needs flushing and refilling.

Call ADK

Glycol chiller systems serve breweries, pubs, wine cellars, bakeries, and industrial process cooling across London. When they underperform, the consequences are immediate — warm beer, failed batches, out-of-spec production. ADK engineers diagnose and repair glycol chiller systems on site, from pump replacements and condenser cleans to full compressor swaps and glycol system recommissions. Call us and we’ll get your temperatures back where they should be.

The post Glycol Chiller Not Cooling Enough — Causes and Solutions first appeared on ADK Kooling.

A walk-in freezer that can’t hold -18°C is a ticking clock. Every degree above target accelerates quality loss and eventually creates a food safety problem. The legal requirement under UK food safety regulations is that frozen food must be stored at -18°C or below. Anything above -12°C and you’re in territory where an EHO would take a very dim view.

We handle this type of problem frequently for businesses in Central London and the surrounding area. If your system is showing these symptoms, our emergency breakdown service team can usually diagnose the root cause on the first visit.

Here’s what causes freezers to lose temperature — and what you can do about it.

Damaged Door Seals and Strip Curtains

The door is the weakest point in any walk-in freezer’s insulation envelope. The primary seal — a heated magnetic gasket around the door frame — prevents warm air ingress and stops ice forming on the frame. Behind the door, most walk-in freezers also have PVC strip curtains that act as a secondary barrier when the door is open during loading.

When the door gasket wears, tears, or loses its magnetic grip, warm moist air enters constantly. You’ll see the signs: ice buildup around the door frame, frost on the floor near the threshold, and the compressor running longer and harder than normal. Damaged or missing strip curtains make every door opening a major thermal event — warm air floods in and it takes the system minutes to recover.

Replacing door gaskets and strip curtains is one of the most cost-effective freezer repairs. The energy savings alone often pay for the parts within weeks.

Defrost Heater Failure and Ice Buildup

Walk-in freezer evaporators accumulate ice during normal operation — it’s unavoidable when you’re cooling air below zero. The defrost system — typically electric heaters embedded in the evaporator coil — activates several times a day to melt this ice and keep the coil clear. The meltwater drains away through a heated drain line.

When a defrost heater element fails, ice builds up on the affected section of the evaporator. Over days, this ice spreads until it encases the entire coil. Airflow through the evaporator drops to almost nothing. The freezer temperature creeps up even though the compressor is running flat out — because the ice is insulating the coil from the air it’s supposed to be cooling.

If the drain line heater fails, meltwater refreezes in the drain and eventually blocks it. The next defrost cycle produces water with nowhere to go — it pools under the evaporator and freezes into a solid mass on the floor of the freezer. We’ve chipped out ice blocks the size of a suitcase from neglected drain lines.

Dirty Condenser

The condenser — either remote on the roof or integral to the refrigeration pack — rejects the heat extracted from the freezer. A dirty condenser can’t reject heat efficiently. Discharge pressure rises, the compressor works harder, energy consumption spikes, and the system gradually loses its ability to pull down to -18°C.

On rooftop condensers, the usual culprits are urban grime, pollen, pigeon feathers, and nesting material. On condensers in plant rooms, poor ventilation compounds the problem. Condenser cleaning is the single most important item on any freezer maintenance schedule.

Low Refrigerant From a Leak

Refrigerant charge should remain constant for the life of the system. If it’s dropping, there’s a leak. Low charge reduces the evaporator’s cooling capacity — the compressor runs longer but can’t pull the temperature down. In a freezer application, even a 10-15% charge loss can mean the difference between holding -18°C and struggling at -12°C.

Under F-Gas regulations, leaks must be found and repaired before recharging. Simply topping up a leaking system is illegal and pointless — the refrigerant escapes again and you’re back where you started. We locate leaks using electronic detectors and nitrogen pressure testing, repair the joint or component, vacuum the system, and recharge to the correct weight.

Compressor Weakness

Compressors wear over time. Valve plates erode, piston rings lose their seal, and the compressor’s pumping efficiency drops. A worn compressor might hold -14°C on a mild day but can’t pull down to -18°C when ambient temperatures rise or after a defrost cycle. Measuring suction and discharge pressures against the manufacturer’s expected values tells us whether the compressor is delivering its rated capacity or whether it’s tired.

This problem often goes hand in hand with cold room evaporator icing up. If you are noticing both symptoms, it is worth getting an engineer out before the system fails completely. We have also covered commercial freezer noise problems in a separate guide.

Too-Frequent Door Openings

During a busy service, kitchen staff may open the walk-in freezer door dozens of times in an hour. Every opening lets in a slug of warm, humid air. The system has to cool that air back down and deal with the moisture, which adds to the ice load on the evaporator. If the freezer is borderline — ageing equipment, partially blocked condenser, slightly low on gas — heavy door traffic during peak service can push it over the edge.

Practical solutions: batch your trips to the freezer, keep the door open for the shortest time possible, make sure strip curtains are intact and hanging correctly, and consider a fast-action door if the traffic volume justifies it.

Failed Evaporator Fan

Evaporator fans circulate cold air around the freezer. When one fails, temperature distribution becomes uneven — the area near the coil stays cold while remote corners warm up. The average temperature rises and the temperature logger may alarm even though the coil is still producing cold air. In multi-fan evaporators, losing one fan may not cause an immediate alarm but will gradually degrade performance.

HACCP and Temperature Logging

Under HACCP requirements, freezer temperatures must be monitored and logged. If your system uses an automated logger with alarms, make sure the alarm thresholds are set correctly and that alerts actually reach someone who will act on them. The Kensington hotel we mentioned at the start had the right equipment — they just didn’t have the right process for responding to overnight alarms.

Freezer Not Holding Temperature? Call ADK

A freezer fault is an emergency. Stock value at risk, compliance at risk, and the clock is ticking. We respond to walk-in freezer breakdowns across London 24/7 with F-Gas certified engineers who carry common parts on every van. Call 020 3974 1419 — we’ll get your freezer back to -18°C.

The post Walk-In Freezer Not Holding Temperature — What to Check first appeared on ADK Kooling.

Display fridges exist to display product. When the glass mists up, the fridge fails at its primary job. The food is still cold, but nobody’s buying what they can’t see. Here’s what causes it and how to fix it.

We see this issue regularly in Shoreditch. A proactive PPM agreement is the best way to prevent this fault from recurring, and it means faster response times if you do need an refrigeration installation.

Worn or Damaged Door Gaskets — The Most Common Cause

The rubber gaskets around the doors of a display fridge create an airtight seal that keeps warm, humid shop air out of the cold cabinet. When gaskets crack, lose their magnetic grip, tear, or deform from years of use, warm air leaks in continuously. That warm air carries moisture. When the moisture hits the cold glass, it condenses. Misting.

Run your hand slowly around the perimeter of a closed door. If you can feel cold air escaping at any point, the gasket has failed at that section. On multi-door display units, it’s often the most-used door — the one staff open hundreds of times a day for restocking — that goes first.

Gasket replacement is straightforward and relatively inexpensive. We carry common profiles for the major manufacturers. It’s one of the highest-value repairs in commercial refrigeration — a new gasket improves display visibility, reduces energy consumption, and extends the life of the compressor by reducing its workload.

Failed Anti-Sweat Heaters

Most glass-door display fridges have low-wattage heaters embedded in the glass panels or the door frames. These anti-sweat heaters keep the glass surface just warm enough to prevent condensation forming on the outside. On some units, heated glass also prevents internal misting by maintaining a slight temperature differential across the pane.

When these heaters fail, the glass temperature drops to match the cabinet interior, and any humidity in the surrounding air condenses on it. The failure can be partial — one door mists while the others stay clear — or total if the heater circuit has tripped or the controller has failed.

Diagnosing a failed anti-sweat heater requires checking the heater resistance and the controller output. On some units, the heaters run continuously; on energy-efficient models, they’re controlled by a humidity sensor and only activate when condensation risk is high.

Overloading and Blocked Airflow

Display fridges rely on a carefully designed airflow pattern to maintain even temperatures and keep moisture under control. In upright glass-door units, cold air flows from vents at the top or back, circulates across the shelves, and returns to the evaporator at the bottom. Overfilling the shelves or pushing products right up against the back wall and air vents disrupts this airflow.

When circulation stalls, cold spots form near the evaporator while warmer pockets develop near the glass. The temperature differential between the glass surface and the air behind it creates condensation. The solution is disciplined stock loading — follow the load line markers inside the cabinet. They’re there for a reason.

High Ambient Humidity

Some environments are just harder for display fridges. A shop next to an open kitchen, a deli with a constantly boiling bain-marie, a convenience store in a basement with poor ventilation — all generate high ambient humidity that overwhelms the cabinet’s ability to manage condensation.

If the gaskets are fine and the anti-sweat heaters are working but you’re still getting misting, the environment is the problem. Solutions include improving shop ventilation, reducing humidity sources, or upgrading to cabinets with more aggressive anti-condensation systems.

Evaporator Fan Failure

The evaporator fans inside the cabinet circulate cold air and maintain the air curtain effect on open-front displays. When a fan fails, the air curtain collapses and warm shop air floods into the cabinet. On closed-door units, a dead fan creates uneven temperatures and stagnant pockets of moist air that condense on the coldest surfaces — usually the glass.

This problem often goes hand in hand with commercial fridge not cooling. If you are noticing both symptoms, it is worth getting an engineer out before the system fails completely. We have also covered walk-in fridge temperatures running too high in a separate guide.

Listen for the fans when the cabinet is running. If it’s quieter than usual or you can see that one of the fan blades isn’t spinning, that’s your culprit. Fan motors on display cabinets are small, inexpensive, and quick to replace.

Incorrect Temperature Setting

A cabinet set colder than it needs to be creates a bigger temperature gap between the glass and the surrounding air, increasing condensation risk. If the cabinet is set to 0°C but the products only need 5°C, you’re creating unnecessary condensation and wasting energy. Set the temperature to the warmest safe point for your product — typically 2–5°C for most chilled display applications.

Night Blinds on Open-Front Displays

Open-front display cabinets — the multideck units common in convenience stores and supermarkets — rely on an air curtain to separate cold cabinet air from warm shop air. During trading hours, this works reasonably well. Overnight, without the air curtain fans running at full speed, these cabinets are vulnerable to humidity ingress.

Night blinds are pull-down covers that seal the open front of the cabinet outside trading hours. Using them consistently reduces overnight energy consumption by up to 30% and dramatically cuts condensation problems the next morning. If your open-front displays are misting up at the start of each day, check whether night blinds are fitted and whether staff are actually using them.

Display Fridge Misting Up? Call ADK

Misted-up display cabinets cost you sales every hour they’re fogged. We diagnose and fix the root cause — gaskets, heaters, fans, airflow, controls — across all major display fridge brands. Call 020 3974 1419 for a fast response across London.

The post Display Fridge Misting Up Inside — Causes and Fixes first appeared on ADK Kooling.

A beer cellar should sit between 11–13°C for cask ales and around 3–5°C for keg products if you’re running a remote python system. When the cooler overshoots and the cellar drops below freezing, you’ve got a fault that needs fixing before it destroys more stock.

We handle this type of problem frequently for businesses in South London and the surrounding area. If your system is showing these symptoms, our PPM team can usually diagnose the root cause on the first visit.

Here’s what actually causes a cellar cooler to freeze up — and what to do about it.

Failed or Miscalibrated Thermostat — The Most Common Cause

The cellar thermostat tells the cooler when to run and when to stop. It’s a simple concept: cellar gets too warm, cooler kicks in; cellar reaches target temperature, cooler switches off. When the thermostat fails, it either sticks in the “on” position — calling for cooling permanently — or drifts out of calibration so it’s reading the wrong temperature.

Mechanical thermostats with a capillary sensor are common on older cellar coolers. The capillary tube is filled with a gas that expands and contracts with temperature, operating a switch. If the tube gets kinked, the bulb corrodes, or the switch mechanism wears out, the thermostat can stick closed. The cooler runs without stopping until the cellar hits sub-zero temperatures.

Digital controllers are more reliable but not immune. A failed sensor gives the controller a false reading, and it responds accordingly. We’ve seen controllers reading 18°C when the cellar was actually at 4°C — the system was cooling aggressively against a phantom heat load that didn’t exist.

Stuck-Open Solenoid Valve

On cellar cooling systems with a remote condensing unit, a solenoid valve in the refrigerant line opens when the thermostat calls for cooling and closes when it’s satisfied. If the solenoid valve sticks open — usually from a burnt coil or debris on the valve seat — refrigerant flows continuously regardless of what the thermostat says.

The giveaway is that the thermostat clicks off (you can hear it) but the evaporator keeps running cold. The compressor eventually cycles on its own controls, but the damage is done — the cellar overcools between thermostat signal and compressor shutdown. Solenoid valve replacement is a standard repair and usually resolves the issue immediately.

Iced-Up Evaporator Coil

The evaporator coil inside the cellar is where the actual cooling happens. Under normal operation, it runs cold but shouldn’t ice up. When ice forms on the coil, it insulates the surface and blocks airflow — the system cools less effectively, so it runs longer, which creates more ice. It’s a downward spiral.

Ice on the evaporator points to one of several problems: low refrigerant charge from a leak (the coil runs colder than design temperature), a failed defrost cycle (if the system has one), a faulty evaporator fan that’s not moving enough air across the coil, or an ambient cellar temperature that’s already too cold for the system’s design parameters.

A cellar cooler with a block of ice on the evaporator needs a controlled defrost — turn it off, let the ice melt completely, then investigate the root cause before restarting. Chipping ice off the coil damages the fins and can puncture the tubing.

Poor Cellar Insulation or Ventilation

Some cellars are naturally cold — underground, stone walls, no heating. In winter, the cellar might sit at 8–10°C without any mechanical cooling. A cooler sized for summer loads will short-cycle or overshoot badly in these conditions because the heat load has dropped to almost nothing.

We have written a separate guide on beer cellar cooling problems which covers a related failure mode worth checking. Similarly, our article on glycol chillers not cooling enough explains another common cause of the same underlying issue.

Conversely, a poorly ventilated cellar where the condenser is also located in the cellar space creates a heat loop — the condenser dumps heat into the cellar, the cooler removes it, the condenser dumps more. The system works harder than it should, and temperature control becomes erratic.

The condenser needs adequate ventilation to outside air. If it’s in the cellar, the cellar needs proper airflow to dissipate the rejected heat. Without this, the system fights itself.

Getting the Temperature Right

Target cellar temperatures vary depending on what you’re storing and serving:

• Cask ale: 11–13°C — too cold kills the flavour and condition; too warm and it goes off fast
• Keg beer and lager: ideally the cellar sits at 11–13°C with a python cooling system chilling the beer to 3–5°C at the point of dispense
• Wine storage: 10–14°C depending on type

A cellar at -2°C is as damaging as one at 20°C. Frozen cask ale is ruined. Frozen keg lines burst fittings. Even bottled stock can crack if the cellar drops far enough below zero.

What to Do Right Now

1. Turn the cellar cooler off at the isolator — stop the overcooling immediately
2. Check the thermostat setting — it should be set between 11–13°C for a standard beer cellar
3. Look at the evaporator coil — if it’s a block of ice, leave the cooler off until it’s fully defrosted
4. Check if the evaporator fan is running when the cooler is on
5. Call an engineer to diagnose the root cause before restarting

Cellar Cooling Problems? Call ADK

We maintain and repair cellar cooling systems across London’s pubs, bars, and restaurants. Thermostat replacement, solenoid valves, evaporator defrosts, full system health checks — we carry the parts and know the systems. Call 020 3974 1419 for same-day cellar cooling repairs.

The post Cellar Cooler Freezing Up — Why Your Beer Cellar Is Too Cold first appeared on ADK Kooling.

Refrigerant leaks are the silent drain on commercial HVAC and refrigeration systems. A system can lose 20-30% of its charge before it actually stops cooling, and in that window it’s consuming significantly more energy, running the compressor harder, and heading toward a failure that’ll cost far more to fix than the leak itself.

We see this issue regularly in North London. A proactive emergency breakdown service agreement is the best way to prevent this fault from recurring, and it means faster response times if you do need an PPM.

Visual Signs of a Refrigerant Leak

• Oil stains around pipework joints — refrigerant carries compressor oil through the system. Where refrigerant leaks out, oil leaks out too. Look for dark oily residue on pipe connections, flare joints, and valve stems
• Ice formation on pipework — a leak at a specific point can cause localised icing as the refrigerant expands through the leak point. A frost line on a pipe where there shouldn’t be one is a strong indicator
• Bubbles in the sight glass — if the system has a liquid line sight glass (common on commercial refrigeration), persistent bubbles indicate low charge
• Oil on the floor beneath the outdoor unit — often the first visible sign of a significant leak from the compressor area

Performance Signs

• Reduced cooling capacity — the system runs but doesn’t cool as well as it used to. Rooms take longer to reach temperature, or never quite get there
• Compressor running longer — longer run times to achieve the same result
• Higher energy consumption — the electricity bill tells the truth even when the thermometer lies
• Ice on the evaporator coil — low refrigerant charge causes the evaporator temperature to drop below freezing, and moisture in the air freezes on the coil
• Short cycling — if the charge drops far enough, the low-pressure switch starts tripping

F-Gas Regulations and Leak Checks

Under UK F-Gas regulations, commercial systems above certain charge thresholds must have mandatory leak checks at specified intervals. The purpose is both environmental (fluorinated refrigerants are potent greenhouse gases) and practical (a leaking system is a system heading for failure). Simply topping up a leaking system without finding and repairing the leak is illegal under F-Gas regulations — and it’s a waste of money because the new refrigerant will leak out the same way.

If you are also experiencing condensing units tripping on high pressure, the two faults may share a common cause. Our engineers frequently find that addressing one resolves the other. You might also want to read our guide on a cold room compressor running constantly for additional troubleshooting steps.

If you suspect a leak, call 020 3974 1419. We’ll pressure test the system, locate the leak, repair it, and recharge to the correct specification. All F-Gas documentation included.

The post Refrigerant Leak Signs in Commercial Systems — What to Look For first appeared on ADK Kooling.