Heater displays E06 and will not start; often associated with exhaust or vent temperature issues.

Safety: Turn off power and gas before removing panels. Hot flue surfaces can cause burns.

Steps:

• Check vent termination: Inspect the vent outlet for obstructions (leaves, nests, ice). Ensure required clearances around the vent per Lochinvar installation manual.
• Inspect air intake (if applicable): For sealed-combustion models, verify the intake pipe is clear and properly connected.
• Examine flue sensor wiring: Locate the flue temperature sensor on the exhaust collector. Check for loose, corroded, or damaged wires. Reseat the connector on the control board.
• Reset and test: After clearing any obvious blockages and confirming wiring, restore power and call for heat. If E06 returns quickly, the flue sensor may be faulty or the heat exchanger may be restricted.

Do not modify venting or gas input yourself. If venting is suspect or the heater is older with possible scale, schedule professional service to inspect the heat exchanger and verify combustion.