Heatwave care: keeping commercial refrigeration working at 45 °C

Why heat hurts refrigeration

A refrigerator moves heat from the cabinet into the room. To do that, the condenser must be hotter than the air around it. As the room gets hotter, the condensing temperature and pressure rise, the compressor draws more current, cooling capacity falls and run time climbs. At some point the unit simply cannot remove heat as fast as it enters, and the cabinet temperature drifts up.

Heat also arrives from inside: warm stock, frequent door openings and hot air pouring in when doors open. In a heatwave, both effects peak together.

Know your unit's rated ambient

Each refrigerator is designed to hold its rated cabinet temperature up to a certain room temperature. For household refrigerators, this is expressed as a climate class under IEC 62552, where class T (tropical) covers rooms up to 43 °C. Commercial cabinets are tested under different methods, so ask the supplier directly what room temperature a model is rated for. A unit rated for 32 °C will not hold temperature in a 45 °C room, however well it is maintained. If your kitchen regularly exceeds the rating, plan ventilation or move the unit.

Before summer arrives

• 1. Deep-clean all condenser coils, including grease. This is the single most effective step.
• 2. Check condenser fans run freely; replace any noisy or slow fan motors.
• 3. Restore the ventilation gap the manufacturer specifies at the back, sides and top. Clear stored boxes from above top-mounted units.
• 4. Have a technician check performance and electrical condition, including current draw and voltage at the socket at peak hours.
• 5. Check door gaskets and closers — a leaking door costs much more in a 45 °C room.
• 6. Make sure temperature alarms work and someone will see or hear them.

Cool the air around the unit

• Keep units out of direct sunlight; draw blinds on glass shop fronts in the afternoon.
• Do not position units beside tandoors, fryers, ovens or dishwasher exhausts. A metre of separation or a heat shield helps.
• In small, closed rooms, add an exhaust fan high on the wall so hot air from condensers can escape.
• Shade remote condensing units on terraces from direct sun, without blocking airflow around them.
• Do not spray water on condensers of self-contained units; it reaches electrical parts and leaves scale.

Use the cabinet wisely

• Load only chilled or frozen product. Cool cooked food first rather than putting it in hot.
• Restock in the cooler morning or evening, not at 3 pm.
• Plan door openings; group restocking into one opening.
• Leave space for air to circulate — packed cabinets have warm spots.
• Do not lower the thermostat set point to compensate; it lengthens run time, can ice the evaporator and does not add capacity.

Voltage in a heatwave

Peak air-conditioning demand pulls voltage down in many areas on summer evenings, exactly when the refrigerator is working hardest. Low voltage makes compressors draw more current and run hotter, and repeated low-voltage starts damage them. If you see lights dimming or the compressor struggling to start, have the supply measured and consider a correctly sized stabiliser or voltage protection for each large unit.

Warning signs in the heat

• Cabinet temperature rising through the afternoon and recovering only at night.
• Compressor running continuously or tripping and restarting.
• Very hot air from the condenser grille or a hot cabinet side.
• Burning smell or clicking from the machine compartment.
• Any of these deserve a service call now, before the unit fails at the busiest point of the season.

Safety notes

Isolate power before any cleaning in the machine compartment. Hot compressors and discharge pipes can burn; let them cool. Most new commercial units use hydrocarbon refrigerants such as R290; keep the area around them ventilated and free of ignition sources, and use only technicians trained for flammable refrigerants for any repair.