The short answer
On a UD refrigerator the usual explanation for a cabinet that will not cool is a supply problem at the socket rather than a dead compressor: the controller watches the voltage it is fed and stops cooling before it flattens a battery, and it does that with the panel still lit. Work the order below rather than the order of expense: the two cheapest checks settle most of these before a tool comes out.
What you actually observe
- The compressor starts, runs a short while, then stops and starts again — Short cycling like this is the signature of a supply the controller keeps rejecting.
- The box holds a mild chill but never reaches the set point — Heat is getting in as fast as it comes out, which is a seal, a load or an airflow problem.
- It cools on mains power but not from the vehicle socket — That isolates the fault to the DC supply path and nothing else.
- The compressor is silent and the display shows nothing at all — NEAR MISS: that is a dead supply or a blown plug fuse, and it belongs on the will-not-start reading of this fault, not here.
- Body: No two UD listings share a base number, so each one in the table is a distinct machine rather than a revision of its neighbour.
Causes, most likely first on the UD platform
- 1. Frost on the evaporator plate — Frost builds quietly over weeks, especially on a unit opened often in humid air. By the time an owner notices the temperature, the plate is wearing a coat. It moves up on UD because the two listings share a cabinet layout, and that layout decides where the heat has to go.
- 2. A lid that no longer clamps — The gasket is the only thing between the compartment and the day outside. Second on UD: it is as common as the cause above it but takes longer to prove, so it is checked afterwards.
- 3. Supply voltage and the battery-protection cutoff — Voltage at the plug is not voltage at the compressor.
- 4. The control module on the compressor — The small module bolted to the compressor is what starts it and sets its speed.
What to check first on these UD models, and why
- 1. Look at the plate for frost thickness — A coated plate is both the symptom and the cause; empty and defrost before judging anything else.
- 2. Close the lid on a sheet of paper and pull — A sheet that slides out with no drag marks the part of the seal that is not clamping.
- 3. Run it from a known-good supply for a while — Swapping supplies separates the whole DC path from the appliance in one move, with no tools.
Before you open anything
Safety
Isolate before you open anything. Unplug the appliance or switch off its breaker, and remember that a capacitor can hold a charge after the power is off. Never defeat the fuse in a DC plug to keep a unit running, and never pierce or cut a refrigerant line to see whether there is charge in it.
Models in the UD family — The listings this family covers; it is a family page, not a model page.
Reference| Model number | Family key |
|---|---|
| UD45 | alpicool:refrigerator:ud |
| UD55 | alpicool:refrigerator:ud |
When to call a technician
Call once the supply, the airflow and the seal are all clean and the cabinet still will not fall. Call immediately if you see oil around the compressor or smell anything burning: oil outside the tubing means the sealed system is open, and every hour it runs after that costs more to put right.
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.
