Answer
Mar 27, 2026 - 09:50 AM
On a Hayward pool heater, "LO" is an error code that stands for "Low" and typically indicates a problem with water flow or an issue with the pressure switch. This means the heater is not detecting enough water flow to operate safely, which could be caused by a dirty filter, closed valve, or malfunctioning pump. Check the water flow and ensure all equipment is functioning properly to resolve the issue.
