Poolex pool heater displays Fb and stops; may occur during defrost or startup.
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.
Possible Causes
How to Fix / Troubleshooting
Safety: Power off the unit before accessing internal refrigeration components. Do not attempt to open the refrigerant circuit.
User-level checks:
- Power cycle: Turn off power for several minutes, then restart to see if Fb clears (temporary logic error).
- Listen for valve shift: When the unit starts or enters defrost, you should hear a distinct whoosh or click from the reversing valve. Absence may indicate a stuck valve or failed coil.
Technician-level checks:
- Measure voltage at the reversing valve coil when the control calls for defrost or heating.
- Test coil resistance; replace with a Poolex reversing valve coil if open or shorted.
- If the valve is mechanically stuck, the entire Poolex four-way reversing valve may need replacement, which requires refrigerant recovery and recharging.
Because this fault involves the sealed refrigerant system, contact a qualified heat pump technician for repair.
Repair Difficulty
Required Part
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