Dishwasher runs but water stays cold, poor drying, E09 displayed.

Safety first: Disconnect power at the breaker and close the water tap. Heating components carry mains voltage.

• 1. Confirm symptom: Run a hot program (e.g., intensive). After 15–20 minutes, open the door carefully. If the water is cold and E09 appears, the heater circuit is likely faulty.
• 2. Access heater assembly: On many Constructa dishwashers, the flow-through heater is integrated with the circulation pump under the tub. Remove the lower front panel or side panel to access.
• 3. Visual inspection: Look for burned connectors, melted plastic, or discoloration around the heater terminals. Ensure all plugs are firmly seated.
• 4. Resistance check (for experienced DIYers): With the heater disconnected and using a multimeter, measure resistance across the heater terminals. An open circuit (infinite resistance) indicates a failed heater.
• 5. Do not bypass safety devices: Never bridge thermostats or safety cut-outs; they are critical for safe operation.

When to call a technician: Heater replacement often requires removing the dishwasher and partially dismantling the hydraulic system. This is best handled by a professional.