Washer does not heat water; cycles take unusually long or stop with E05.

Safety first: Unplug the washer and allow it to cool before accessing the heater. Water and electricity are a dangerous combination.

Step-by-step checks:

• Access the heater: On most Grundig washers, the heater is mounted at the bottom of the rear of the tub. Remove the rear panel to expose the heater terminals and NTC sensor.
• Test the heating element: Disconnect the heater wires. Measure resistance across the heater terminals with a multimeter. Typical values are 20–30 Ω (check Grundig specs). If the circuit is open or shows a short to ground (test between each terminal and the metal tub), replace the heater.
• Check the NTC sensor: The NTC is usually clipped into the heater bracket. Disconnect its connector and measure resistance at room temperature (often 20–30 kΩ). Warm it gently with your hand; resistance should decrease smoothly. If readings are erratic or open, replace the NTC sensor.
• Inspect wiring and connectors: Look for heat damage, discoloration, or loose spade connectors at the heater and NTC. Repair or replace any burnt connectors and ensure tight fit.
• Control board relay: If heater and NTC test good, the heater relay on the main PCB may be faulty. Visual inspection may show pitting or burning. Replacement of the PCB is recommended and should be done by a qualified technician.