Wine cabinets and wine coolers

A kitchen refrigerator is asked to sit somewhere in the high thirties and nobody notices a degree either way. A wine cabinet is asked to hold two zones a few degrees apart, with enough humidity that corks do not dry, in a room that swings twenty degrees between February and August. There is very little margin in that, so a fault that a refrigerator would absorb shows up here as zones converging or a top shelf that reads warm.

It also means the room is part of the diagnosis. A cabinet sweating at the door seal in a humid basement in August may be behaving exactly as designed while the room is the problem, and taking it apart will not help.

• Evaporator fan bearing — the first symptom is usually the noise carrying, not the temperature
• Zone control or its sensor, giving two zones that slowly converge on one another
• Door seal hardened or set flat, which shows as condensation before it shows as drift
• Condenser blocked in built-in cabinetry, especially a toe-kick grille with a rug in front of it
• Control board, on units that have ridden out a decade of power interruptions
• Compressor or sealed system, which is where the economics change

Small freestanding coolers are often thermoelectric: no compressor, a solid-state module and a fan. They are quiet, they struggle in a warm room, and when the module goes there is very little in them worth repairing. Built-in wine storage of the kind fitted into a kitchen or a bar run is compressor-driven and built like a refrigerator, which is exactly why it is worth servicing.

If you are not sure which you have, the model plate settles it in a sentence — and it changes the advice completely.

A fan motor, a seal, a sensor, a zone control or a board in a built-in cabinet is nearly always the better spend. Replacement wine storage starts from $3,500 for the appliance alone, before delivery, installation or the joinery an integrated unit is trimmed into — and a fitted cabinet is rarely a straight swap for whatever is on the shop floor.

Where it turns is a sealed-system failure in an older undercounter unit that is also noisy and whose seal has gone. At that point we say so plainly on the first visit, rather than after two parts orders.

• Read the temperature at a bottle with a separate thermometer, not off the display
• Clear whatever is in front of the lower grille and check the coil is not felted with dust
• Do not set both zones to the same figure — a dual-zone cabinet needs a gradient to work
• Watch whether the drift tracks the weather, which points at the room rather than the cabinet