FLO2
Hot Spring
Secondary Flow Fault / Heater Flow Switch Error
Display shows “FLO2”; spa may shut down or heater disabled.
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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.
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Possible Causes
Stuck heater flow switch, Wiring issue between flow switch and IQ control box, Intermittent circulation pump, Debris in plumbing restricting flow
How to Fix / Troubleshooting
Safety first: Shut off power at the GFCI breaker before inspection.
- Confirm circulation: With power restored briefly, verify that the circulation pump runs and water moves through the heater return. Then turn power back off.
- Inspect heater flow switch: Find the heater flow switch (often a paddle or pressure-style switch on the heater manifold). Check for loose spade connectors, corrosion, or broken wires. Reseat connectors firmly.
- Check for debris: Remove filters and visually inspect the skimmer and suction fittings for blockages. Flush the lines by running the jets with filters removed for a few minutes.
- Reset power: After confirming good flow and connections, power the spa back on and monitor for the error. If it returns, the flow switch may be defective.
Persistent FLO2 errors usually require replacement of the flow switch or further diagnostics on the control board by a Hot Spring technician.
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Repair Difficulty
Hard
4/5
Required Part
Heater Flow Switch
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