Hayward Universal H-Series gas pool heater error codes

Plain-English meanings and step-by-step fixes, sourced from the manufacturer manual.

• Error IF· ignition failure
• Error CE· communication error
• Error LO· limit string open
• Error AO· blower vacuum switch open
• Error SF· temperature sensor fault
• Error HS· water temperature sensing error
• Error IO· igniter circuit open
• Error bD· gas valve or control board fault