LG Dryer PF: Power Was Lost During a Cycle

PF means the dryer lost and regained electrical power while a drying cycle was active. The board detected a clean startup with a cycle still logged as in-progress — something interrupted the power supply and it came back.

Is This Normal?

A single PF after a storm, breaker trip, or brief power outage is completely expected. The dryer is telling you "I was running, I lost power, and now power is back." Clear it by pressing Start (the dryer resumes the interrupted cycle) or by pressing Power to cancel and start fresh.

Clearing PF

To resume the interrupted cycle: Press Start/Pause. The dryer picks up approximately where it left off. On sensor-dry cycles, the moisture sensor recalibrates within the first minute of resumed tumbling.

To cancel and start fresh: Press Power (off), then Power (on), select a new cycle, and press Start. The previous cycle's progress is discarded.

If PF will not clear: Unplug the dryer for 60 seconds, then plug back in. If PF appears without any cycle having been running, the board's non-volatile memory has a corruption error. This is rare and indicates a board-level issue.

When PF Is a Problem

Recurring PF without known power events indicates an electrical supply issue:

Loose Power Cord Connection (35%)

The dryer's 3-prong or 4-prong power cord plugs into a NEMA 10-30 or 14-30 outlet. These heavy-duty outlets handle 240V at 30A — the plug and outlet contacts carry significant current. Over time, the outlet's spring contacts lose tension. The heavy plug gradually works loose from its own weight and vibration from the dryer.

A plug that barely holds in the outlet creates a high-resistance connection. During the heater's high-current phase (20-25 amps), this resistance causes a voltage drop severe enough that the board's power supply browns out momentarily — registering as a power loss.

Test: Push the plug firmly into the outlet. If it slides in easily or does not hold its own weight, the outlet contacts are worn. Replace the outlet ($10-25, electrician recommended for 240V work).

Cord Terminal Block (25%)

Inside the dryer's rear access panel, the power cord connects to a terminal block with three or four lugs and nuts. These connections carry the full 30A load. If any nut has loosened, that junction becomes a high-resistance point that heats, arcs, and eventually causes intermittent power loss.

Inspect (unplug first): remove the rear terminal access cover. Check each lug nut for tightness. Look for heat discoloration (blackened or blue-tinted metal), melted insulation, or arc marks on the terminal surfaces. Retighten any loose connections. If arcing damage is visible, clean the contact surfaces with fine sandpaper before retightening.

External Power Grid Issues (25%)

If PF coincides with flickering lights or other household electronics resetting, the problem is upstream — either the utility's grid or your home's main panel. Smart dryers like LG models with sensitive control boards detect micro-interruptions that older mechanical dryers would ride through.

Neighborhood pattern: Ask neighbors if they experience similar issues. Rolling brownouts, aging transformers, and construction on local power lines all cause micro-outages.

Internal Board Power Supply (15%)

The board's capacitors and voltage regulators can degrade after 8-10 years. A weakened power supply section fails to maintain stable voltage during the heater relay's switching transient — the relay closing creates a brief current spike that a healthy power supply handles but a weak one cannot.

Diagnosis clue: PF appears within the first 2-3 minutes of every heated cycle (when the heater first energizes) but never on air-only cycles.

PF and Wet Clothes

If PF interrupted a sensor-dry cycle near the end, the clothes may be nearly dry but the cycle timer reset. Press Start to resume — the sensor will detect the low remaining moisture and end the cycle quickly. If PF interrupted early in the cycle, resuming adds the remaining time. No need to restart from zero.

PF on Gas vs. Electric LG Dryers

Gas LG dryers run on 120V standard outlets. A loose 120V plug is more likely to cause PF than a loose 240V plug because 120V outlets have lighter-duty contacts. On gas dryers, PF from a loose plug is the leading cause of recurring codes.

Electric dryers' 240V circuits are heavier-duty but carry much higher current, so terminal block looseness is more common as a PF source.

Parts and Cost

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LG dryer showing PF repeatedly? We check the circuit, cord, terminal block, and board power supply — most PF causes are simple connection issues. Book electrical diagnosis.