Display shows E4 and burner will not ignite (gas models only)

Safety first: Turn off electrical power and close the gas shutoff valve before working on any gas components. If you smell gas, evacuate the area and contact your gas supplier or emergency services.

Steps to check:

• Verify that the manual gas shutoff valve to the CTC water heater is fully open and that other gas appliances in the home are working.
• Remove the burner access cover and visually inspect the igniter electrode and flame sensor. Look for cracks, heavy soot, or corrosion.
• Clean the igniter and flame sensor gently with fine emery cloth or a non-abrasive pad. Do not bend the electrodes out of position.
• Check the wiring harness from the igniter/flame sensor to the main control PCB for secure connections.
• Restore power and gas, then observe the ignition sequence through the sight glass if available. If there is no spark or no gas flow, the ignition module on the main control PCB or the gas valve assembly may be faulty.
• Replacement of the gas valve or control board should be performed by a licensed gas technician.