Water heater will not ignite; display shows E01 shortly after a hot water tap is opened.

Safety first: Turn OFF gas at the shutoff valve and switch OFF electrical power to the water heater before working on it. Allow the unit to cool completely.

• Check gas supply: Verify the manual gas shutoff valve to the Alpha gas valve assembly is fully open. Confirm other gas appliances in the home work normally.
• Inspect burner area: Remove the burner access panel. Look for soot, rust flakes, or debris blocking the main burner orifice on the Alpha burner assembly. Gently clean with a soft brush and compressed air (do not enlarge the orifice).
• Check ignition electrode: Locate the Alpha ignition electrode/igniter near the burner. Inspect for cracks, heavy carbon buildup, or a bent tip. Clean the tip with fine emery cloth and ensure the gap to the burner surface matches the specification in the Alpha service manual (typically 3–5 mm).
• Inspect wiring: Confirm the igniter lead is firmly connected to the spark module on the Alpha control board and not shorting to the chassis.
• Reset and test: Restore power and gas, then open a hot water tap. Observe through the sight glass: you should see sparking and ignition. If E01 returns and there is no spark or no gas flow, the ignition module or gas valve assembly may need replacement.

Stop and call a qualified technician if you smell gas continuously, see damaged gas piping, or are not comfortable working around gas components.