Washer-dryer displays 4H and may stop heating water during wash cycles.

Safety first: Unplug the unit and allow internal components to cool before servicing.

Steps to troubleshoot:

• Confirm symptom: On a hot or sanitize cycle, check if the glass door or tub area warms up after 15–20 minutes. If not, suspect heater issues.
• Access heater: Remove the rear panel to locate the wash heater element mounted in or under the tub.
• Inspect wiring: Check for burnt or loose wires at the heater and associated thermostats.
• Test heater element: With power disconnected, remove one wire from the heater and measure resistance across the terminals. An open circuit indicates a failed element.
• Check high-limit thermostat: Test continuity across any thermostats mounted on the heater housing. Replace if open.
• Replace faulty components: Install a new wash heater element or thermostat as needed, ensuring all seals and gaskets are properly seated to prevent leaks.

If 4H persists after heater and thermostat replacement, the main control board may not be energizing the heater circuit and should be checked by a technician.