Display shows 'Err' or 'Error' and oven functions are locked out.

Safety first: No internal work is usually required for this error, but always avoid using the oven if there is a burning smell or visible damage.

• 1. Reset the clock: Many Rangemaster ovens will not operate unless the time is set. Press the clock button and use the +/- or arrow keys to set the correct time, then confirm.
• 2. Cancel all programs: Press and hold the cancel/stop button for several seconds to clear any active timers or delayed start programs.
• 3. Power reset: Turn off power at the mains for 5 minutes, then restore. This can clear temporary software glitches.
• 4. Check user manual: Some models display 'Err' if an invalid combination of functions is selected. Verify that you are using a supported mode.
• 5. If persistent: If 'Err' reappears immediately after power-up and correct clock setting, the control board or keypad may be faulty and require professional diagnosis.