HAYWARD H250 LO Code

Water Pressure Switch (2 PSI)

The 'LO' code signifies the limit string is open, and the water pressure switch is the most common mechanical failure point in this circuit. This switch ensures the heater only fires when water is circulating; its internal diaphragm frequently fails or becomes clogged with calcium/debris, preventing the contacts from closing even when flow is adequate.

SKU: HDXWPS1930

High Limit Switch Kit

If the water pressure switch is functioning, the high-limit switches are the next components in the limit string. These sensors trip if the heat exchanger exceeds safe temperature thresholds; they can fail electrically (opening the circuit permanently) or trigger prematurely due to scaling inside the heat exchanger.

Pool Filter Cartridge / Sand Media

While not a heater component, a dirty filter is the leading external cause of the 'LO' code. Reduced GPM (gallons per minute) prevents the pressure switch from closing. Cleaning or replacing the filter media often restores the necessary 25 GPM required for the H250 model to operate.