The short answer
On a built-in cabinet, poor cooling is usually restricted ventilation, a busy door or a warm room rather than a failed system. Check that air is actually moving at the grille before anything else: a blocked grille explains most of these on its own.
What you actually see and hear
- Cool but never cold, with the compressor running almost constantly — Heat cannot leave the cabinet. Grille, housing or room temperature.
- Fine overnight, poor during the evening — Door openings. The cabinet recovers when it is left alone, which is the clue.
- Frost on the back wall inside with warm shelves — Airflow inside the cabinet has stopped, or the thermostat is calling for far too much.
- Completely warm and silent — Power, thermostat or start circuit rather than heat load.
- NEAR MISS - drinks on the door shelf are warmer than the rest — Normal in any cabinet, and more pronounced in a small one.
Causes, most likely first on this machine
- Blocked or restricted ventilation grille — First on a built-in cabinet. Flooring laid over the plinth, a dust mat on the grille or an airtight housing all trap the heat the cabinet is trying to reject.
- Door openings and warm loading — Second. A cabinet loaded with room-temperature bottles and opened constantly spends the whole evening catching up, and it never does.
- Room temperature — Third. A cabinet in a conservatory, a garden bar or beside an oven has a much harder job than the same cabinet in a cool kitchen.
- Door seal and door alignment — Fourth. Under-counter doors take knocks from feet and stools, and a slightly misaligned door leaks cold air all day.
- Thermostat setting or failure — Fifth, and easy to rule out with a thermometer and a day of patience.
- Condenser fan, start relay or compressor — Last. A genuine fault, and it is what remains once the installation has been cleared.
Check in this order, and why
- Put your hand at the grille with the compressor running — Moving warm air means the cabinet is rejecting heat. Still air is the diagnosis.
- Put a thermometer inside and read it in the morning — An overnight reading with no door openings separates the cabinet from its use.
- Count the door openings in an evening — If overnight is fine and evenings are not, the use is the fault.
- Check the seal with a sheet of paper all round — Quick, and under-counter doors get knocked more than most.
What an owner can safely check
- Clear the grille and vacuum the condenser behind it — The first and most productive thing to do on any built-in cabinet.
Tools: vacuum, soft brushAbout 20 min
- Pull the unit out and run it clear of the housing for a few hours — If it cools properly out of the housing, the housing is the fault.
Tools: thermometerAbout 240 min
- Chill bottles before loading and keep the cabinet reasonably full — Warm loading is the hidden half of most bar-fridge complaints.
About 10 min
- Test the door seal with paper and clean the seal and frame — Under-counter doors take more abuse than kitchen ones.
Tools: paper, clothAbout 15 min
- Set the thermostat mid-range and leave it a full day — Judge by thermometer, not by how the bottles feel.
Tools: thermometerAbout 10 min
- STOP HERE if the compressor never runs or clicks repeatedly — Start circuit or sealed system, and neither is an owner job.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel - a capacitor can hold a charge after the power is off. An under-counter cabinet sits in a housing with a live outlet behind it that you cannot see, so switch off at the breaker before pulling the unit out. The compressor and its relay stay hot and live until the unit is unplugged.
When to call a technician
Call when the cabinet has clear ventilation, a good seal, a sensible load and still will not reach forty degrees Fahrenheit overnight with the door shut - that points at the thermostat, the fan or the sealed system. Call an installer rather than a technician if the housing has no ventilation path at all, because no appliance will work properly in a sealed box. If the cabinet is storing food rather than drinks, treat the temperature as a food-safety question and move anything perishable while you diagnose.
Nearest pages of this class
What this page does not cover
This page is written for the under-counter beverage refrigerator class, not for one family or model line. Where a brand- or model-specific page exists for your unit it is the more specific answer and it is linked above, so go there first if your machine is named. What is deliberately not here: compressor and fan part numbers, thermostat ranges, door hinge specifications and cabinet cut-out dimensions, all of which differ by family and belong on the page for that family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
