Water heater locks out with F2, fan starts but ignition does not occur or stops quickly.

Safety: Isolate electrical power and turn off gas before opening the appliance. Only proceed if you are comfortable working around gas appliances.

• Visual inspection: Remove the front cover. Locate the ignition electrode assembly at the burner. Check for cracked porcelain, broken tips, or signs of arcing to the casing.
• Clean electrode: Lightly clean the electrode tips with fine abrasive pad. Do not file aggressively or change the shape of the tips.
• Check electrode gap: Using the Ideal technical data for your model, verify the spark gap with a feeler gauge. Adjust gently if obviously misaligned.
• Inspect ignition lead: Ensure the high-voltage lead is firmly connected at both the electrode and the ignition transformer on the control board. Look for burn marks or damaged insulation.
• Test operation: Reassemble, restore gas and power, and reset the heater. If F2 persists, the ignition transformer or control board may be faulty and a professional should replace the parts.