Dryer runs but does not heat, or stops with E04 after a few minutes; drum rotates normally but clothes stay cold.

Safety first: Disconnect mains power. Heating components can remain hot after use; allow cooling time.

Step-by-step checks:

• Confirm no heat: Run a short cycle on a high heat setting and feel the air at the exhaust or inside the drum after 3–5 minutes. If it remains cold, proceed.
• Access the heater assembly: On most Proline dryers, remove the rear panel to expose the heater housing. Visually inspect for burned spots, broken coils (for visible elements), or melted connectors.
• Test the heating element: Disconnect the heater terminals. Use a multimeter to measure resistance across the element. A typical reading is between 20–40 Ω (varies by model). An open circuit indicates a failed element.
• Inspect wiring and connectors: Check for heat-damaged spade terminals or discoloured wires. Replace any burnt connectors and trim back to clean copper before fitting new terminals.
• Check thermostats and thermal cut-outs: While at the heater, test all inline thermostats for continuity. Replace any that are open.

When to call a technician: If the heater and thermostats test good but E04 persists, the heater relay or triac on the main control board may be faulty and require board-level repair or replacement.