The short version
A ZKS refrigerator that runs continuously and still will not hold temperature is telling you that cold is being made and not delivered. On this family the delivery path — evaporator, defrost, fan — is where the fault sits far more often than the sealed system, which is the opposite of the order a reader arrives with.
The observable signs on this platform
- The run never ends — The compressor no longer cycles off, because the control never sees the setpoint reached.
- Condensation or soft ice cream in the freezer — The freezer is losing ground too, just more slowly than the fresh-food side. A freezer holds food safely at 0 °F (−18 °C) or below.
- The cabinet is warm but the compressor is clearly running — You can hear it and feel warmth at the condenser, yet the air inside never gets cold.
- NEAR MISS — the cabinet is silent and nothing is cold — No hum, no fan, no light behind the controls means a supply, start-relay or main-board fault, and that is a different page.
Causes, most likely first on the ZKS family
- Frosted evaporator from a stalled defrost cycle — The top of the list, and the reason every other entry sits where it does.
- Evaporator fan motor stopped or dragging — Next, because it gives you the same warm box with no frost to explain it.
- Condenser coil blinded by dust or pet hair, or a stopped condenser fan — A capacity problem rather than a failure.
- Thermistor or control board reporting a temperature the cabinet does not have — Diagnosed by contradiction: the display says one thing and a thermometer on the shelf says another.
The order to work in, and the reason for it
- 1. Hold the freezer door switch closed and listen for the fan — You are asking one question: is air being moved at all?
- 2. Take a proper look at the freezer rear panel — A continuous frost sheet with a running fan means defrost.
- 3. Work the machine compartment: coil, fan, clearance — Pull the cabinet out, look at the condenser coil, watch its fan, and check nothing is packed against the back.
Safety first
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. The freezer rear panel on this family sits over the evaporator fan and often over a defrost heater, so treat both as live until the plug is out of the wall, and never hold the door switch closed with tape while your hands are inside the compartment.
Models in the ZKS family — The model numbers this page covers.
Reference| Model number | Family key |
|---|---|
| ZKS300TST3IU | bertazzoni:refrigerator:zks |
| ZKS300TST6IU | bertazzoni:refrigerator:zks |
| ZKS360TST3IU | bertazzoni:refrigerator:zks |
When to call a technician
Call once the two freezer-side checks and the condenser check are clean, because what is left is sensor and control work that needs a meter and a wiring diagram. Call immediately, without further testing, if you smell burning, see oil outside the tubing at the compressor, or the cabinet is warm and the compressor is hot and silent — all three point at the sealed system or the compressor itself, where the tools and the licence stop being owner tools. On this family the practical line is the freezer rear panel: what is in front of it is yours, what is behind it usually is not.
Other problems covered for the ZKS family
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
