Bradford White · Heat pump RE2H (-1NCWT models)
Bradford White Heat pump RE2H (-1NCWT models) error code F21
What it means
Application Update Failure. A problem occurred while updating the control application.
The manual says the control must detect this 1 time(s) before the code is displayed.
What Bradford White says to do
These steps involve electrical testing or parts replacement. Bradford White's manuals tell owners to leave that work to a qualified service technician.
Cycle power and try to complete the update again. If problems persist, reflash software or replace the control board.
Last checked 2026-10-03.
Safety first
- DISCONNECT POWER BEFORE SERVICING. IMPORTANT: RECONNECT ALL GROUNDING DEVICES. All parts capable of conducting electrical current are grounded; grounding wires, screws, straps, clips, nuts or washers removed for service must be returned to their original condition and properly fastened. (p.1)
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.
- Bradford White AeroTherm (RE2H…-1NCTT models): F21
- GE GeoSpring DEEJS / DFEJS (2015–2016): F21
- GE Profile GEOSPRING Smart (PF / PH, 2025 on): F11, F21