E18
Atlantic
Internal I²C/SPI Sensor Bus Failure
E18 error and thermostat reports internal sensor bus fault (multiple sensors offline).
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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
Shorted sensor IC on internal bus, Damaged PCB traces, ESD damage to bus lines, Firmware crash affecting bus initialization
How to Fix / Troubleshooting
Safety first: Turn off power to the thermostat before opening the housing.
- Step 1 – Power cycle: Disconnect power for 2–3 minutes, then restore. Observe if E18 returns immediately.
- Step 2 – Factory reset: Perform a factory reset to reinitialize all internal buses and sensors.
- Step 3 – Visual inspection: Remove the front cover and inspect the PCB for any obvious damage near sensor ICs (temperature, humidity, pressure). Look for burn marks or cracked components.
- Step 4 – Replace front module: Because internal sensor buses are not serviceable in the field, replace the thermostat front module or entire thermostat if E18 persists.
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Repair Difficulty
Medium
3/5
Required Part
UI PCB with Integrated Sensor Bus
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