Display shows H0 or a similar code and the unit will not heat, though the display and fan may operate.

Safety first: Unplug the air fryer before accessing the control board.

• Step 1 – Confirm symptom: Start a cook cycle and verify that the fan runs but no heat is produced (no warmth at exhaust after several minutes).
• Step 2 – Access control board: Remove the top or rear cover to expose the main control board. Identify the heater relay (usually a small rectangular component near the heater connectors).
• Step 3 – Inspect solder joints: Check the underside of the board for cracked or dull solder joints at the relay pins. Reflowing solder should only be done by someone experienced with electronics.
• Step 4 – Test relay output: With the unit unplugged, trace the heater circuit from the relay to the element. If the element and wiring are good (tested separately), the relay is likely not closing.
• Step 5 – Replace board: In most home repair scenarios, replace the entire main control board rather than the individual relay, to ensure reliability.

Warning: Working on live circuits is dangerous. Do not test relay operation with the board exposed unless you are trained and using proper safety precautions.