Skip to content
REFRIGERATION

Troubleshooting

Walk-in cold room not cooling

This is general guidance for any walk-in cold room. A cold room works like a large refrigerator split in two: an evaporator unit inside with fans, and a condensing unit outside, often on a roof or wall, joined by refrigerant pipes. When the room warms up, the cause can be at either end, or in between. Indian conditions are hard on both: outdoor units bake in direct sun and collect dust, plastic bags and bird nests, while doors in busy kitchens and warehouses stay open far longer than designers assumed. Many rooms also run on three-phase supply, which adds failure modes that a plug-in refrigerator does not have.

First, check these

  1. Read the room temperature with a probe thermometer and check the controller for the setpoint, a defrost icon or an alarm code.
  2. Check the door: is it closing fully, is the strip curtain intact, and has it been left open during loading?
  3. Inside, check the evaporator fans are running and the coil is not a solid block of ice.
  4. Outside, check the condensing unit fans are spinning, the coil is not blocked by dust, leaves or plastic, and nothing is stacked against it.
  5. Check the electrical panel for tripped MCBs or a phase-failure or voltage-protection relay showing a fault.
  6. Check that stock is not stacked against the evaporator or blocking the air throw across the ceiling.

Likely causes

  1. 1. Door left open or strip curtain missing

    You can check this

    Signs: Room warms during loading, fog rolling out of the door, frost around the frame, strips torn off.

    Fix: Keep the door shut between trips, repair or replace the strip curtain, and plan loading so the door is not propped open. Fit or repair a door closer.

  2. 2. Outdoor condensing unit blocked or overheated

    You can check this

    Signs: Condensing unit in direct sun, coil dusty, debris or nests in the fins, fans slow or stopped, high-pressure trips on hot afternoons.

    Fix: Isolate power and clear loose debris and dust from the coil face. Shade the unit without blocking airflow. Coil washing and fan repairs need a technician.

  3. 3. Evaporator iced up

    Technician job

    Signs: Thick ice on the coil, weak airflow, water or ice under the evaporator.

    Fix: A technician should check the defrost heaters, drain line heater, termination sensor and defrost schedule.

  4. 4. Airflow blocked by stock

    You can check this

    Signs: Cartons stacked to the ceiling or against the evaporator, warm pockets at the back of the room.

    Fix: Keep a clear space in front of and below the evaporator and leave gaps between stacks and walls so air can circulate.

  5. 5. Supply or phase problem

    Technician job

    Signs: Compressor not running, phase-failure relay tripped, low voltage on one phase, MCB tripped.

    Fix: An electrician should check the supply and protection devices. Do not reset repeatedly without finding the cause.

  6. 6. Refrigerant leak or component failure

    Technician job

    Signs: Compressor runs but the room does not cool, partial frost on the coil, oily stains at joints or valves.

    Fix: A refrigeration technician must diagnose and repair. Long pipe runs and many joints make leak testing important.

When to call a technician

Call a technician if the room does not start recovering within a couple of hours after you have closed the door, cleared airflow and checked the outdoor unit, if any fan has stopped, if ice keeps returning, or if protection devices trip. Move high-risk stock to other cold storage early; large rooms take many hours to pull down once warm.

Before entering a cold room, make sure the inside door release works and someone knows you are inside. Isolate power before touching any fan or coil. Outdoor units on roofs need safe access. Refrigerant and electrical repairs are for trained technicians only.

Book a service visit