LO / HLS
Hayward
Flow-Related Overheat Cycling
Heater alternates between LO and HLS; unit short-cycles and water temperature rises slowly.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Undersized pump for heater, Excessive bypass around heater, Partially blocked internal passages, Misadjusted external bypass valve
How to Fix / Troubleshooting
Safety First: Turn off power before adjusting valves near the heater.
- Check bypass valve: If an external bypass is installed, adjust it per Hayward's instructions so adequate flow passes through the heater.
- Verify pump size and speed: Ensure the pump is capable of the minimum flow rate required by the heater. Increase speed on variable-speed pumps when heating.
- Clean filter and baskets: Any restriction upstream can reduce flow and cause overheating.
- Consult hydraulics: If symptoms persist, have a pool professional evaluate the plumbing design and heater sizing.
Advertisements
Repair Difficulty
Medium
3/5
Required Part
External Bypass Valve
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements