GE heat pump water heater shows F12 and may not heat water in heat pump mode.

Safety: Turn off power at the breaker. The reversing valve is part of the sealed system; do not open refrigerant lines.

Steps to check F12:

• Listen for valve operation: When the unit switches modes, you should hear a distinct click from the reversing valve area. No sound may indicate a coil or control issue.
• Inspect wiring: Locate the reversing valve coil and verify the connector is secure and wires are intact.
• Check coil resistance: With power off, disconnect the coil and measure resistance. Compare to GE specs. An open coil indicates failure and requires replacement.
• Control output: With power on and extreme caution, verify that the control board is sending voltage to the coil when a mode change is commanded. If not, the board may be faulty.
• Professional service: If the coil is good and powered but the valve does not shift, the valve itself may be stuck internally and will require a sealed system technician to replace.