Bradford White · AeroTherm (RE2H…-1NCTT models)

Bradford White AeroTherm (RE2H…-1NCTT models) error code bAd linE (F12)

What it means

The voltage is too low at power-up. The control monitors the input line voltage one minute after power-up, and if the voltage is below 155 VAC, the fault code will be displayed.

The manual says the control must detect this 1 time(s) before the code is displayed.

Source: Heat Pump Water Heater Installation & Operation Instruction Manual (RE2H50S*-1NCTT, RE2H65T*-1NCTT, RE2H80T*-1NCTT), 238-52169-00C (ECO 8424), page 29

What Bradford White says to do

If "bAd line" is shown on the display, the water heater is not receiving the correct voltage as a result of incorrect wiring. Turn the power OFF to the water heater, correct the wiring issue, then turn the power back ON. Contact a certified technician to assess and repair the water heater based on the fault codes.

Source for these steps: Heat Pump Water Heater Installation & Operation Instruction Manual (RE2H50S*-1NCTT, RE2H65T*-1NCTT, RE2H80T*-1NCTT), 238-52169-00C (ECO 8424), page 17

Last checked 2026-10-03.

Safety first

DANGER: Shut OFF power to the water heater before draining water to avoid risk of shock. (p.23)
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.22)
Fault codes should only be used to help identify components which require testing. Never replace a part based solely on a fault code. The control can generate a false fault if the right conditions exist. (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.