FA
Protherm
Non-Volatile Memory Error
Thermostat shows FA and schedules or settings are frequently lost after power interruptions.
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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
Corrupted EEPROM/flash memory, Repeated power surges, Aging of memory cells, Firmware bug affecting data storage
How to Fix / Troubleshooting
Safety: Turn off power before removing the thermostat from the wall.
- Step 1 – Perform a soft reset:
- Use the reset option in the thermostat menu (if available).
- Allow the device to reboot and re-test.
- Step 2 – Factory reset:
- In the installer menu, select Factory Reset.
- Reconfigure system type, schedules, and Wi‑Fi settings.
- Step 3 – Stabilize power supply:
- Ensure the thermostat is powered from a stable circuit.
- Consider installing a surge protector for the boiler/thermostat circuit.
- Step 4 – Firmware update:
- If the thermostat supports OTA updates via app, check for and install the latest Protherm firmware.
- Step 5 – Replace thermostat if FA persists:
- Persistent FA indicates failing memory hardware.
- Replace the Protherm smart thermostat main unit.
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Repair Difficulty
Medium
3/5
Required Part
Protherm Smart Thermostat Main Control Board
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