The short answer for these models
A refrigerator that hums away without getting cold has almost always stopped delivering cold air rather than stopped making it. Frost over the evaporator, a door that is no longer sealing and a condenser smothered in dust account for most of these, and all three are visible without a meter. The sealed system is the expensive answer and also the least likely one. On the BUF refrigerators the brand-level answer holds and the order does not: a built-under cabinet has to shed its heat through one small grille, so anything that restricts that grille shows up as a fault long before it would on a freestanding unit, so the clearance and condenser checks come before the rest on these models.
What you observe
- The BUF form you own, which changes what the rest of this list means — Look at how the unit sits. A cabinet in a cut-out breathes through one grille, and that grille joins the suspect list ahead of anything inside the machine.
- Food near the cold source freezes while the rest stays warm — One end of the cabinet is doing all the work and the other end is getting none of it.
- The sides or the back of the cabinet are hot to the touch — The flanks or the rear are warm enough to notice, which means the heat being removed has nowhere to go.
Causes, most likely first on this family
- The thermostat, the sensor or the control — It sits below the mechanical causes because it is rarer, and because the checks above will have ruled most of it out by elimination. The ranking moves here for a reason particular to these models: how the unit is built changes what this finding means. That is what puts the clearance and condenser checks ahead of everything else on the list.
- The sealed system or the compressor — It comes last because every cheap cause above has to be excluded before anyone opens a refrigerant circuit, which is licensed work.
What to check first, and why that order
- First — shut the door on a strip of paper and pull — Do it at several points around the frame. Anywhere the paper slides out without resistance is a leak, and it takes a minute to find.
- Second — look at the cold source for frost — Empty enough of the compartment to see the rear wall or the cold plate. A carvable sheet of ice tells you the answer before any tool comes out. On these models this is the step the construction changes: what you found at the step above decides how much weight to give what you find here.
Before you open anything
Safety
Cut the power before a panel is disturbed, because a capacitor can hold a charge after the power is off. Defrosting with heat is how liners crack and coils get punctured; time and an open door are the only safe method. Empty the cabinet before moving it and get a second pair of hands for the weight.
Where the owner job ends
The owner half ends at the free checks. Once the seal grips, the vents are clear, the coil is clean and the thermostat is where it should be, whatever is left sits behind a panel or on the sealed side and needs a technician. Mention any frost pattern you found; it is the most useful thing you can hand over.
The other symptoms covered for this family
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
