Bradford White · AeroTherm Series G2
Bradford White AeroTherm Series G2 error code 12
Evap Outlet Sensor - T3B Fault
What it means
T3b sensor (evaporator outlet temperature) fault. The control detects the thermistor output is at or nearly shorted or open circuit.
Also listed in: Quick Service Guide, Heat Pump Water Heaters AeroTherm Series (Service Manual Supplement), 238-55219-00A, page 1
What Bradford White says to do
The manual gives no specific step for this code. Check the troubleshooting and maintenance sections on the AeroTherm Series G2 page, or call a qualified technician.
Last checked 2026-10-03.
Safety first
- WARNING: Turn OFF the electrical supply to the unit before installation and before removing any access panels to service the heater. (p.3, p.24)
- DANGER: Shut OFF power to the water heater before draining water to avoid electrocution. (p.29)
- CAUTION: For your safety, do NOT attempt to repair the water heater or any of its parts. Refer any repairs to a qualified service technician. (p.28)
From the manufacturer's manual for this series.
The same code on other models
Codes mean different things on different heaters. Match the series to the model number on your rating label.
- LG Inverter heat pump (2020 manual): 12
- LG Inverter heat pump APHWC501M / 801M (2024–2025 manuals): 12
Other AeroTherm Series G2 codes
- 1 (Lower Temp Sensor - T1 fault)
- 3 (Lower Element Fault)
- 4 (Upper Element Fault)
- 5 (Control Fault)
- 6 (Supply Voltage Fault)
- 7 (Tank Over Temp Fault)
- 8 (Fan Fault)
- 9 (Compressor Fault)
- 10 (Superheat Fault)
- 11 (Airflow Restriction)
- 13 (Evap Inlet Sensor - T3A Fault)
- 14 (Compressor Outlet Sensor - T4 Fault)
- 15 (Ambient Sensor - T5 Fault)
- 16 (Ambient Temp Hi/Lo)
- 17 (Compressor Hi Temp Fault)
- 18 (Water Leak Detected)
- 92 (Heating Relay Fault)
- 93 (Element Hard Fault)
- 94 (Condensate Fault)
- 95 (EEV Hard Fault)
- 96 (Superheat Hard Fault)
- 97 (Compressor Hard Fault)
- 98 (Fan Hard Fault)
- 99 (Upper Temp Sensor - T2 fault)