Classeq dishwasher does not heat the wash or rinse water; E3 displayed after some minutes of operation.

Safety first: Isolate the machine from the mains. Heating components operate at full mains voltage and can be submerged in water.

• Confirm lack of heat: Start a cycle and feel the door or tank exterior after several minutes (without opening the door mid‑cycle). If still cold and E3 appears, proceed with checks.
• Access heating elements: Remove front or side panels to locate the tank heater (usually a flange‑mounted immersion heater in the wash tank) and, if fitted, the boiler heater in the rinse boiler.
• Test heater resistance: Disconnect power leads from the heater terminals. Measure resistance with a multimeter. A typical Classeq immersion heater is in the 10–30 Ω range depending on rating. Infinite resistance indicates an open heater that must be replaced. Also check for earth leakage by measuring between each terminal and earth.
• Check temperature probes: Locate the tank NTC sensor and boiler NTC sensor. Inspect wiring and connectors. Measure resistance at room temperature and compare with Classeq specifications (commonly 5–20 kΩ at 20°C). A short or open circuit sensor will cause E3.
• Inspect heater relays and wiring: On the control PCB or separate power board, locate the heater relay(s). Look for burnt contacts, discoloration, or loose spade connectors. Tighten or replace as needed.
• Replace faulty components: If a heater or NTC is out of spec, replace with the correct Classeq‑approved part and new gasket/O‑ring where applicable. Refill, check for leaks, and run a full heat cycle.