Built-in refrigeration can combine separate compartments, model-specific airflow paths and layered controls; the actual design determines the diagnostic approach. Treating it like a freestanding fridge is how expensive mistakes happen.
The diagnostic measures each compartment separately: air temperature, evaporator behavior, damper position and airflow path, defrost timing and termination, and condenser condition and clearance.
Electronics are verified rather than replaced by pattern: sensors and thermistors, control board response, fan operation and door switches, plus the door and gasket condition that can contribute to icing.
Where measurements indicate the sealed system, its performance is evaluated and any refrigerant work is performed only within KONGRA's legal scope or coordinated with properly licensed independent contractors.
Sub-Zero, Miele MasterCool, Thermador, GE Monogram and Fisher & Paykel are used as equipment identifiers only.
Where a freezer stays cold while the fresh-food compartment warms, shared-airflow designs have their own guide. That reasoning is not universal to all built-ins — appliances with separate cooling systems per compartment are investigated differently.