Start with the load, not the plant

Before condemning the refrigeration, check what changed: a door left open, a delivery of warm stock loaded at once, more shelving blocking airflow, or a light left on inside. Cold rooms fail on load as often as on plant.

Mechanical causes

  • Iced evaporator — airflow drops and the room warms even though the plant runs continuously.
  • Refrigerant loss — pressures and superheat readings confirm this; a leak test finds where.
  • Door seals and heater tape — worn seals invite humidity, which becomes ice.
  • Controller or probe fault — the controller reads a temperature the room is not actually at.
  • Condenser fouling — a dirty condenser cannot reject heat, so capacity collapses on hot days.

Protecting stock while you wait

Log the temperature and the time, keep the door shut, move the highest-value stock, and do not stack fresh warm product into a room that is already struggling.