Dishwasher does not heat water; cycles run cold and E3 appears on the display.

Safety first: Turn off power at the breaker and allow the machine to cool completely before accessing heaters.

• Check tank heater element: Access the main tank heater terminals under the tank. Disconnect wires and measure resistance with a multimeter. An open circuit indicates a failed heater that must be replaced.
• Inspect booster heater (if installed): For Insinger models with an external booster, test the booster element in the same way. Verify that the booster’s high-limit reset is not tripped; reset if necessary according to the manufacturer’s instructions.
• Test high-limit thermostat / temperature probe: Locate the high-limit thermostat on the tank or booster. Check for continuity at room temperature. A high-limit that remains open must be replaced. For electronic probes, compare resistance to the service chart.
• Control board heater relay: If all heating components test good, inspect the control board for a failed heater relay (burn marks, melted solder). Replacement of the control module is usually required if the relay is defective.
• Verify supply voltage: Confirm that the correct voltage (often 208–240V for commercial Insinger units) is present at the heater terminals during a heat call.