F1 — Heat exchanger generates no heat
F1 indicates the heat-producing component (heat exchanger on hybrid/heat-pump models or heater assembly on conventional) is not generating heat as commanded. The cycle aborts because clothes will not dry.
- Keep using it?
- Limited use only
- DIY difficulty
- Moderate
- Typical cost
- $120-250
- Verified against
- lg.com ↗
The fix
Main control board
Drive motor or main control board fault
Diagnose first: Indicates a motor-circuit fault; the control board is the more common failure point.
Find this part on Amazon →Didn't resolve it? Next suspect: Drive motor ($80-180)
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How to fix it
- Unplug for 60 seconds to attempt a soft reset.
- On electric models, access and test the heating element, thermal fuse, and high-limit thermostat for continuity; replace any open one.
- On heat-pump models, confirm the unit sat upright at least 4 hours after any move; if longer was needed and you skipped it, wait the full 24 hours.
- If element/fuses are good and F1 returns, monitor heater relay operation on the main board.
- Heat-pump sealed-system or compressor failures require a certified appliance tech — do not attempt DIY.
- Document the model/serial and schedule LG service if non-DIY components are suspect.
Why it happens
Typical signs: F1 on display · Drum tumbles but air stays cold · Cycle ends with damp clothes · Recent move of a heat-pump unit
- Open heating element (electric) Element coil failed open.
- Open thermal fuse / hi-limit (electric) Safety device tripped from prior overheat.
- Compressor not running (heat-pump) Compressor start fault — see also LE2.
- Refrigerant loss (heat-pump) Sealed-system leak.
- Failed main / inverter control board Board not commanding the heat source.
Other parts sometimes needed
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
More LG dryer codes
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: lg.com.