The short answer
On a Ostba refrigerator, condenser coil blanketed with dust, lint or insects is the usual answer when the unit runs but the cabinet is warm — not a failed compressor. This is a compact cabinet — a small sealed box with its condenser tucked behind or beneath it, and that shapes the order below. These are fitted under a counter in an office or a small kitchen, which means a cutout, a fixed position and very little airflow at the back.
What you observe
- The cabinet is warm while the unit is plainly running — You can hear it working and feel air moving, but nothing inside is cold.
- It never stops — there is no quiet period at all — A healthy cabinet cycles. One that runs without a break is one that is never reaching its setpoint.
- One area is cold and the rest is not — Cold at the plate or the vent and warm at the door means an airflow problem rather than a cooling one.
- NEAR MISS — the unit is silent, dark and nothing is cold — No light, no fan, no hum means no power reaching it or a failed start component. That is a different fault and a different page; leave this one.
Causes, most likely first on this platform
- Condenser coil blanketed with dust, lint or insects — A dust blanket on the coil is a thermal blanket: the refrigerant cannot dump its heat, so the compressor runs and runs while the cabinet slowly warms. Anything that depends on air behind the cabinet is therefore compromised before the appliance has done anything wrong.
- A stalled defrost cycle with the evaporator iced over — On an automatic-defrost cabinet the failure is quiet: the defrost heater or its control stops clearing the coil, ice builds behind the rear panel over weeks, airflow drops to nothing and the cabinet warms while the compressor runs normally.
- Heat load the cabinet was never rated to shed — Warm surroundings shift everything: the run time climbs, the compressor never catches up, and a unit that was fine in the kitchen fails in a garage or a sunroom.
Check in this order, and why
- First: look at the condenser coil with a torch before touching anything — A matted coil is visible in seconds and is the most common owner-fixable cause on this platform. On a unit fixed into a cutout, start with what the cutout is doing to the air behind it.
- Second: take out the lower drawer and look at the rear wall for frost — You are testing the top-ranked mechanical cause without removing a panel or using a tool.
- Third: read the temperature where the unit actually stands — Second, because it is the other half of the same question: the cabinet can only work against the air it is given.
What an owner can safely check
- Clear the condenser coil at the back or underneath — Vacuum it, then brush what the vacuum leaves. A matted coil produces exactly this symptom and the fix costs nothing.
Tools: vacuum, soft brushAbout 20 min
- Empty the cabinet, switch it off and leave the door open overnight — If cold returns afterwards and then fades again over days, the defrost system is your cause and it needs a technician.
Tools: cooler, iceAbout 45 min
- STOP HERE if the next step needs a meter on live terminals — Reading a defrost heater, a thermostat or a compressor winding means touching energised terminals behind a panel. That is where an owner check ends and a service call begins.
Before you open anything
Safety
Unplug the refrigerator or switch off its breaker before removing any panel — a capacitor can hold a charge after the power is off. Leave the door switch wired exactly as it is: it cuts power to the internal fan when the door opens, and defeating it puts a moving blade under your hand. Never chip ice off an evaporator or a cold plate with a knife, a screwdriver or any other tool — the tubing behind it is thin-walled, and a punctured line ends the appliance on the spot.
When to call a technician
Call once the checks above are clean, or immediately if you see oil on or under the compressor — oil outside the tubing means the sealed system is open and every hour it runs after that costs more to put right. Refrigerant work is licensed work and the tools to do it are not owner tools.
Nearest pages of this class
What this page does not cover
This page is written for the appliance class and this symptom, not for one family or model line. Where a family- or model-specific page exists for your unit, it is the more specific answer and it is linked from the sibling list — go there first if your model is named there. Deliberately not here: wiring colours, board part numbers, torque figures and the exact panel-removal sequence, all of which differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
