Display shows E12 and unit will not ignite; fan may run continuously (gas models)

Safety first: Turn off power and gas. Combustion and venting issues can lead to carbon monoxide hazards.

Steps to check:

• Inspect the intake and exhaust vent terminations outside the building for obstructions.
• Locate the air pressure switch inside the CTC water heater and inspect the silicone tubing for cracks, kinks, or disconnections. Reattach or replace tubing as needed.
• With power off, disconnect the tubing from the pressure switch and gently blow through it to ensure it is clear.
• Test the pressure switch with a multimeter for continuity when the blower is running (requires advanced skills).
• If the switch does not close when the blower runs and venting is clear, replace the air pressure switch. If the blower does not run or is weak, replace the combustion blower assembly.