LG Dishwasher Won't Fill — Water Supply and Valve Troubleshooting

When your LG dishwasher starts a cycle but no water enters the tub, the unit either sits idle (waiting for water level to reach minimum) or eventually displays error code IE (inlet error) after timing out. LG's control board allocates a specific fill window — typically 8-12 minutes depending on the model — and if the water level sensor does not detect adequate fill within that period, the board aborts the cycle and reports IE.

The water fill system on LG LDT/LDP models is straightforward in design: a single water inlet valve (part number 5220FR2006H) with an integrated mesh screen controls all water entry. The valve opens when the control board energizes its solenoid coil (120V AC) and closes when de-energized via spring return. Upstream, the household supply valve and braided hose deliver water to the inlet valve. Downstream, a short internal hose routes water from the valve into the tub.

Systematic Diagnosis: Outside → In

Work from the water source toward the dishwasher to identify where flow stops:

Check 1: Household Supply Valve

Located under the sink, behind the dishwasher, or occasionally in the basement/crawlspace below:

• Verify the valve is fully open (turned counterclockwise to the stop)
• Gate valves (round handle) should be fully open — even one full turn from fully open restricts flow
• Ball valves (lever handle) should have the lever parallel to the pipe

After plumbing work: Plumbers routinely close dishwasher supply valves during sink work and may forget to reopen them. This is the most common cause of "suddenly won't fill" after any plumbing service.

Check 2: Supply Hose Flow Test

1. Turn off the supply valve
2. Disconnect the supply hose from the dishwasher's inlet valve (10mm wrench at the fitting)
3. Place the hose end in a bucket
4. Open the supply valve briefly
5. Water should flow freely with good pressure and volume

If no flow or weak flow:

• Supply valve may be closed or failed internally (gate valves corrode internally)
• Supply hose kinked behind the dishwasher
• Supply hose internally collapsed (rubber liner delaminated)
• Household pressure issue (ask neighbors or check other fixtures)

If flow is strong: The supply system is functioning — the problem is at or inside the inlet valve.

Check 3: Inlet Valve Mesh Screen

With the supply hose disconnected from the valve:

1. Look into the valve's water inlet port
2. A fine mesh screen is visible (pressed into the port)
3. Inspect for sediment, mineral buildup, or debris clogging the screen
4. Clean with a toothbrush and white vinegar (do not remove the screen)
5. Reconnect the hose and test

LG screen vulnerability: The mesh screen on LG's inlet valve (5220FR2006H) is relatively fine compared to some brands. It effectively traps sediment but also clogs faster in hard-water areas. Annual inspection and cleaning is recommended.

Check 4: Inlet Valve Solenoid Function

If supply pressure and screen are good, the valve solenoid may have failed:

Electrical test:

1. Disconnect power at circuit breaker
2. Access the inlet valve (lower left panel area on most LDT/LDP models)
3. Disconnect the valve's two-wire electrical connector
4. Measure coil resistance: 500-1,500 ohms (varies by model year)
5. Infinite resistance = coil burned out (valve cannot open electrically)

Mechanical test (if coil resistance is normal):

1. Reconnect the valve electrically
2. Restore power and start a cycle
3. Listen at the valve — you should hear a click or buzz when the board energizes it
4. If you hear the valve energize but no water flows (with supply confirmed good), the valve is mechanically seized (diaphragm stuck or plunger corroded)

Check 5: Control Board Fill Command

If the valve is electrically and mechanically sound but receives no voltage:

1. During a fill attempt, measure voltage at the valve connector: should read 120V AC
2. No voltage = control board relay failure (not sending fill command)
3. Run Smart Diagnosis via ThinQ to confirm whether the board logged a fill command

Check 6: Float Switch False Trigger

The base pan float switch can prevent filling if it detects water in the base pan (error AE). Even residual moisture from condensation can sometimes hold the float up on a very sensitive switch:

• Remove the kick panel (4 Phillips screws)
• Check the base pan for any water
• Push the float down manually — it should move freely
• Dry any moisture completely

LG Smart Diagnosis for Fill Failures

Open the ThinQ app or call 1-800-243-0000 for phone audio diagnosis:

• Smart Diagnosis reports whether the fill valve was commanded
• Shows water level sensor readings during the fill attempt
• Differentiates between "no water entered" and "water entered slowly" (restricted flow)
• Identifies whether the failure is upstream (no valve command) or downstream (valve not responding)

Water Pressure Requirements

LG specifies minimum 20 PSI at the inlet valve. The valve's diaphragm mechanism relies on water pressure to assist opening — at very low pressure, even a functioning solenoid may not fully open the valve.

Homes with low pressure issues:

• First-floor units in multi-story buildings during peak usage
• Rural properties with well pumps during low-tank periods
• Homes with multiple simultaneous water demands (shower running while dishwasher fills)

Solution for low-pressure environments: A small booster pump on the dishwasher supply line can bring pressure above the 20 PSI minimum. However, do not exceed 120 PSI (high pressure damages the valve over time).

Repair Costs

Prevention

• Inspect and clean the inlet valve screen annually (takes 5 minutes with a 10mm wrench)
• Replace the supply hose every 5-7 years to prevent internal deterioration
• After any plumbing work in the kitchen, verify the dishwasher supply valve is reopened
• Install a sediment filter on the supply line if you have well water or known sediment issues
• Run Smart Diagnosis via ThinQ quarterly to catch gradually declining fill performance

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