Washer does not heat water; cycle takes unusually long and E05 appears mid-cycle.

Safety first: Unplug the washer and allow it to cool before working near the tub or heater terminals.

• Access heater: On many Primus washers, the heater is mounted at the rear of the tub. Remove the rear panel to expose the heater terminals and NTC sensor.
• Inspect wiring: Look for burnt connectors or loose spade terminals on the heater and NTC. Reseat or replace damaged connectors.
• Test heater element: With a multimeter, measure resistance across the heater terminals. A typical value is 20–40 Ω; infinite resistance indicates an open heater that must be replaced.
• Test NTC sensor: Measure resistance at room temperature; it should be within the Primus specification (often 5–20 kΩ). If reading is open, shorted, or does not change with gentle warming, replace the NTC.
• Replace heater if needed: Loosen the central nut, gently push the bolt inward to release the gasket, and carefully pull the heater out. Clean the mounting area and install the new heater with its seal, tightening the nut evenly to avoid leaks.
• Run a test wash: Reassemble panels, restore power, and run a hot cycle to confirm heating and that E05 is cleared.