Pool heater will not ignite; display shows E01 shortly after a call for heat.

Safety First: Turn OFF power to the heater at the breaker and shut off the gas supply before removing any panels. Allow the heater to cool completely.

Steps to check:

• Verify gas supply: Confirm the gas shutoff valve to the heater is fully open. If other gas appliances are not working, contact your gas supplier.
• Inspect the igniter: Remove the front access panel. Locate the hot surface igniter on the burner tray. Check for cracks, heavy white deposits, or broken wires. If damaged, replace the igniter assembly specified for your Lochinvar model.
• Clean flame sensor: Many Lochinvar pool heaters use a combined igniter/flame sensor or a separate flame rod. Gently clean the metal rod with fine emery cloth or a Scotch-Brite pad to remove oxidation. Do not sand the ceramic insulator.
• Check wiring connections: Inspect the harness from the ignition control board to the igniter and flame sensor. Reseat any loose connectors and look for burned or pinched wires.
• Reset and test: Restore power and gas, then reset the heater according to the user manual. Call for heat and observe ignition. If E01 returns after cleaning and inspection, the ignition control board or gas valve may require professional diagnosis.

When to stop: If you smell gas continuously, hear loud bangs on ignition, or are unsure about gas pressure testing, stop and contact a qualified pool heater technician.