Display shows HL or HFL; spa stops heating and may shut down pumps intermittently

Safety: Turn off power at the GFCI breaker before opening the equipment bay.

• Clean or remove filters: Take out all filter cartridges from the filter well. Rinse thoroughly or temporarily run the spa without filters for testing (do not leave it that way long-term).
• Check water level: Ensure water level is above all suction fittings and at the recommended fill line. Low water can draw air into the system and cause low flow.
• Bleed airlocks: After a refill, loosen the unions on the circulation pump and primary jet pump until water seeps out, then retighten. This purges trapped air that can cause HL errors.
• Inspect pump operation: Restore power and observe the circulation pump and low-speed jet pump. You should see strong water movement at the heater return and in the spa. If a pump hums but does not move water, it may be seized or airlocked.
• Check slice valves: Confirm that all gate/slice valves around the pumps and heater are fully open. A partially closed valve can trigger HL.
• Reset error: Turn power OFF for 2–3 minutes, then ON. If HL clears and does not return with good flow, the issue was likely a temporary low-flow condition.

Persistent HL/HFL with verified good flow may indicate a failing high-limit sensor or control board issue; professional service is recommended.