Check thermostat for temperature and compare with handheld thermometer - are the readings the same of =/- 0.5 degrees?
Does the temperature return to the normal range after 5 minutes?
Is the area around the refrigeration units and/or compressor units clear from combustible materials and other debris?
Are the condensing and evaporator coils clean and free from dust and other built up materials?
Are fan blades free of dust and other built up debris (including fan screens)?
Are evaporator fans within cool rooms and refrigeration units free of stored materials providing complete airflow to the front and rear?
Check any coolant levels
Are coolant levels OK?
Are all hinges, latches and seals in working order providing a well sealed environment?
Is there any exposed Insulated Panel Core (EPS) within cool rooms caused by unsealed service penetrations, delamination or panel damage?