Fors C4

Fors error code C4 indicates: FORS Cool-Line Premium Refrigerator & BioCool Cellar: Diagnostic fault code C4 registered by the microcomputer controller. Thermodynamic loop refrigerant charge under-pressure.

The primary root cause for Fors code C4 is: On FORS appliances engineered with FORS Cool-Line dynamic multi-air circulation, automatic defrost thermodynamic loop, and digital NTC sensor array (10 kΩ / 4.7 kΩ): refrigerant gas leak in sealed circuit Metrological tolerance verification: pressure switch contacts 0.0 Ω closed; trip threshold 35 mbar (350 mm WC)..

To resolve error code C4: Disconnect mains power before servicing. Unplug the harness at the main PCB and use a calibrated digital multimeter: inspect pressure dome for blockages and test switch continuity (0.0 Ω closed). Inspect contacts for pin oxidation or loose terminals. Replace defective part if out of tolerance, re-energize and clear error: Press and hold SuperCool / Alarm Silence button for 5 seconds until display beep confirms normal setpoint restoration and error clear.

Resetting power (unplugging for 5–10 minutes) clears temporary memory errors. However, if Fors code C4 persists, the physical component causing On FORS appliances engineered with FORS Cool-Line dynamic multi-air circulation, automatic defrost thermodynamic loop, and digital NTC sensor array (10 kΩ / 4.7 kΩ): refrigerant gas leak in sealed circuit Metrological tolerance verification: pressure switch contacts 0.0 Ω closed; trip threshold 35 mbar (350 mm WC). must be inspected or replaced.

Set a digital multimeter to ohms (Ω). Disconnect power and test Compressor Motor Windings (Run/Start) & Defrost Heater across Across 3 compressor pins (Common, Run, Start): R(C-S) + R(C-R) = R(S-R). Winding to earth: >20MΩ (OL).. Expected nominal reading is 15Ω–25Ω (Run C-R), 20Ω–35Ω (Start C-S), 200Ω–400Ω (Defrost Heater). PTC Relay: 10Ω–30Ω at 25°C.. Tolerance: ±10%. Any low insulation resistance to casing (<2MΩ) trips the breaker. Defrost bimetal reads <0.5Ω when sub-zero..

Standard electrical safety protocol: 1. Disconnect 230V mains power before opening panels. 2. Verify zero voltage at test points. 3. Allow hot water or heating elements to cool below 30°C before handling.