Heater will not start; display shows E01 shortly after power-up and the burner never ignites.

Safety first: Turn off electrical power to the Kripsol pool heater at the breaker and shut off the gas supply (if gas-fired) before opening any panels. Do not run the heater without proper water flow; this can damage the heat exchanger.

• Check pump and valves: Ensure the pool circulation pump is running at normal speed. Verify that all suction and return valves, including any Kripsol heater bypass valves, are fully open.
• Clean the filter: If the filter pressure is high, backwash or clean the Kripsol sand or cartridge filter to restore proper flow.
• Inspect inlet strainer: Remove and clean any debris from the pump basket and any Kripsol heater inlet strainer or leaf trap.
• Check flow/pressure switch: Locate the Kripsol flow switch or water pressure switch on the heater’s water manifold. Inspect wiring for loose or corroded connections. With power off, disconnect the switch and test continuity with a multimeter while water is flowing (pump on). Replace the switch if it does not close under flow.
• Reset and test: Restore power and gas, then restart the system. If E01 persists after restoring flow and verifying the switch, contact a qualified pool heater technician.