LG Dryer D80/D90 Flow Sense Error

LG D80 and D90 are Flow Sense airflow warnings. LG support describes d75, d80, d90, and d95 as exhaust restriction levels, with D80 and D90 indicating heavy restriction, and notes that hot humid air must vent somewhere or moisture stays in the drum. The important point for a homeowner is that these codes do not automatically mean the dryer’s sensor is bad. They mean the dryer is seeing conditions consistent with restricted exhaust, weak airflow, or in some gas-dryer cases a gas supply condition that must be separated from airflow.

Do not keep running long loads after the warning. A restricted dryer can overheat, shut down, leave clothes damp, and create lint/fire risk. USFA dryer fire guidance points to cleaning lint filters, checking the rear of the dryer for lint buildup, and making sure the venting system is not damaged, crushed, or restricted. The owner-safe path is visible airflow proof, not internal sensor replacement.

Read the code as a restriction clue

D80 means the dryer believes the exhaust path is around the 80 percent restricted range; D90 is more severe. Flow Sense bars or a D95 warning make the same message stronger. The warning can appear with long dry times, hot cabinet, damp clothes, or shutdown. It can also appear after installation when the duct run is too long, kinked, crushed, or has too many elbows. In apartments, the exterior termination may be on a roof, shaft, or shared route that the homeowner cannot fully inspect.

Start with what you can see. Remove lint from the lint filter. Check whether the flexible hose behind the dryer is crushed, kinked, compressed behind the unit, or looped into a coil. If the dryer is running and you can safely reach the outside termination, confirm whether air is moving outside. Weak or no outside airflow with the dryer running is strong evidence that the restriction is outside the drum, not a bad load of clothes.

Safe checks before service

• Clean the lint screen before another test and check for fabric-softener residue that blocks mesh.
• Use a small normal load, not towels or bedding, for any observed test.
• Inspect the visible transition duct behind the dryer for crushing, kinks, sharp bends, or compression.
• Check whether the outside vent flap opens while the dryer runs, if the termination is safely accessible.
• Record whether the warning appears immediately, after several minutes, near the end, or only on heavy loads.
• For gas models, note whether heat starts normally and whether any gas-supply warning or ignition symptom is present.
• Stop if the dryer smells hot, shuts down, or the duct is inaccessible in a wall, ceiling, shaft, or roof run.

Do not remove internal panels, defeat thermostats, disconnect gas, or try to disable Flow Sense. Do not push the dryer back tightly after cleaning the visible hose; that can recreate the same crushed duct. If the warning returns after the visible duct is straight and the lint screen is clean, the restriction may be in the concealed duct or exterior vent.

What D80/D90 does not prove

The warning does not prove the Flow Sense sensor is bad. It does not prove the heater is bad. It does not prove the dryer needs a control board. It also does not prove the entire vent is clean because the lint screen looks clean. Lint can collect in the transition hose, wall duct, roof cap, bird screen, exterior hood, or a long run with elbows. A dryer can move enough air to feel warm at the door and still fail the exhaust restriction check.

Another false assumption is that vent cleaning means the dryer is cleared. If only the short hose behind the dryer was vacuumed, the building duct may still be restricted. If the warning appears in a high-rise or condo, the actual blockage may be beyond what the resident can access. That is why evidence about outside airflow and duct geometry matters.

How to narrow it down

If D80 or D90 appears after installation, focus on duct length, elbows, crushed hose, and termination. If it appears after years of normal use, focus on lint accumulation, exterior flap restriction, roof cap, or a crushed hose after the dryer was moved. If it appears only on towels and bedding, load size and moisture volume may be exposing a marginal vent. If the dryer is electric and also has no heat, use the gas-vs-electric no-heat branch. If it is gas and D80 appears with ignition problems or no heat, record gas supply and flame behavior without disassembling anything.

A useful test is not “run another full cycle.” It is a short, watched cycle with a clean lint filter, small load, and visible duct positioned without kinks. If the warning returns quickly, stop. If airflow outside is weak, call for vent cleaning or building maintenance before appliance parts. If outside airflow is strong and the code returns with the transition duct removed only by a professional, then dryer-side diagnostics may be needed.

NYC apartment context

In NYC, many dryers vent through long concealed routes, roof terminations, exterior walls that residents cannot access, or shared building shafts. Some apartments have ventless dryers or combo units, which should not be diagnosed with this LG vented-dryer Flow Sense path. If your unit is in a closet, stacked, or part of a WashTower, access may require moving the appliance safely and coordinating with the building. Do not climb to a roof, open a shaft, or remove a shared duct.

Building management may need to verify the termination, roof cap, or shared vent route. If the dryer is under warranty, the appliance company may still require proof that the home exhaust path is clear before replacing parts. Save the evidence in a way that separates appliance behavior from building vent behavior.

When to stop

• Stop if the dryer smells hot, shows burning odor, shuts down, or the cabinet becomes unusually hot.
• Stop if the warning returns after one safe visible duct check.
• Stop if the duct route is concealed, roof-terminated, or shared by the building.
• Stop if the dryer is gas and there is ignition failure, gas smell, or no heat.
• Stop if the dryer is stacked or built into a closet and safe access requires moving it.

Evidence to save

Photograph the exact code, Flow Sense bars, lint screen, transition duct behind the dryer, outside vent if accessible, model tag, and the load type. Record how many minutes into the cycle the code appears, whether clothes are hot and damp or cold and damp, whether the dryer shuts down, and whether air moves outside. If a vent cleaner or building staff inspected the duct, save that note too.

If the symptom changes

If the vent route is the real issue in an apartment, use dryer vent clogged in an NYC apartment. If the dryer has no heat and you need to separate gas from electric causes, use dryer not heating: gas vs electric. If the symptom is mainly damp clothes without an LG code, compare dryer clothes still damp or Bosch dryer not drying clothes for the drying-performance branch.

What makes a Flow Sense case hard

The hard cases are the ones where the short visible hose looks clean but the code keeps returning. That does not make the code meaningless. It usually means the proof has to move farther down the exhaust path: wall duct, roof cap, exterior hood, bird screen, booster fan, long run, or crushed section hidden behind the appliance. In a building, that proof may belong to maintenance or a vent-cleaning company rather than the dryer owner.

Record whether the warning appears with the dryer connected to the wall duct and whether airflow is strong at the exterior termination. Do not ask the appliance technician to guess a sensor until the home exhaust path is documented. At the same time, do not let vent cleaning become an endless loop if a qualified vent inspection confirms the duct is open and the dryer still flags the same condition. At that point, dryer-side diagnostics can be justified with evidence.

What to save if the vent is shared or hidden

Apartment and condo dryers often do not have a simple outside wall hood that the resident can inspect. If the duct goes into a wall, ceiling, shaft, or roof, write that down. Photograph the visible transition hose and the closet installation. If building staff or a vent cleaner checks the termination, ask for the finding in writing: blocked, weak airflow, clear, damaged, inaccessible, or shared. That note helps avoid the common loop where the appliance company blames the duct and the building blames the dryer without either side proving airflow.

If the warning happens only when the dryer is pushed back into place, the transition hose position is a prime clue. Pulling the dryer forward for cleaning and then pushing it back can crush the hose again. The final installation position matters. A photo with the dryer in its normal location is often more useful than a photo taken while the hose is temporarily straightened.

Also note whether the code appears with timed dry, sensor dry, or both. A restriction warning across different cycles strengthens the airflow branch. A warning only with oversized loads may show that the vent is marginal and fails under heavier moisture load.

If both cycles trigger D80 or D90 quickly, stop and document the duct path before more drying. A fast repeat code with a clean lint screen is strong evidence that the restriction is not solved by another ordinary load.

Common homeowner questions

Can I clear D80 by unplugging the dryer?

Unplugging may clear the display temporarily, but it does not clear a restricted vent. If the airflow condition remains, the warning can return.

Is D90 worse than D80?

Yes. LG describes the number as restriction severity. D90 should be treated as a stronger stop-and-check airflow warning.

Can a clean lint screen still trigger Flow Sense?

Yes. The restriction can be behind the dryer, inside the wall duct, at the exterior vent, or in a long run with elbows.

Should I replace the sensor first?

No. Prove the exhaust path and installation first. Sensor diagnosis belongs after airflow and duct evidence are clear.