How to Replace LG Dishwasher Check Valve 5220ED4004A and Stop Backflow

Quick answer

LG dishwasher check valve 5220ED4004A is a one-way flap at the sump outlet that stops drained water from flowing back into the tub. When the flap wears or sticks open, dirty water returns after the drain cycle and a sour smell follows. Replacing the valve takes 20 to 30 minutes with a Phillips screwdriver and the part costs $8 to $20.

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Dirty water returning to a freshly drained tub makes a small valve worth checking. The LG dishwasher check valve 5220ED4004A helps water leave without flowing back into the machine. Hose trouble or poor routing can create similar symptoms, so the valve is only one possible cause.

Has the water returned after the drain finished? That detail is more useful than finding water in the tub without knowing when it arrived.

Separate the valve’s job from the drain pump’s before choosing parts. The fit checks and replacement sequence below explain the difference and show how to match the repair to your model.

Quick Facts

Use these details to plan the work:

Difficulty: Easy
Time: 20 to 30 minutes
Tools: Phillips screwdriver, towel, flashlight
Part cost: $8 to $20
Skill level: Beginner

What Does a Dishwasher Check Valve Do?

A dishwasher check valve is a one-way flap in the drain path. It opens during drainage, then closes to prevent wastewater from returning to the tub.

Its condition matters in several ways.

A working flap closes the drain path after water leaves.
A stuck flap can allow backflow into the sump.
A worn flap may fail to seal even when the pump still runs.
Dirt around the flap can affect its movement or seal.

The sump is the collection area beneath the filter. Returning water after drainage suggests a different diagnosis from water that never drains.

Is a Bad Check Valve Causing Dirty Water to Flow Back Into My LG Dishwasher?

A poorly sealing valve allows wastewater back after drainage, while persistent standing water can also involve a blockage, pump failure, or incorrect hose routing.

Compare the pattern before selecting a part.

Symptom	Possible Cause
Water leaves, then returns	Check valve or drain routing
Water never leaves properly	Blocked hose or drain-pump fault
Sour smell after a completed drain	Returned dirty water or trapped debris
Backflow linked to the sink drain	Hose connection or missing high loop

Does the tub empty first and refill with dirty water afterward? That sequence supports a backflow problem. It still does not prove the valve is the only cause, especially when the drain hose is not held in its intended high loop.

Where Is the Check Valve on an LG Dishwasher?

On this LG layout, the valve sits at the sump outlet beneath the filter assembly and becomes accessible after the spray arm, guide tube, and filter assembly are removed.

Keep these parts distinct.

Sump check valve: The flap at the drain port covered by this procedure.
Drain pump: The motor-driven part that pushes water out.
Drain hose: The path from the dishwasher toward the sink drain.
Pump flapper: A related valve design that may appear in a different location on other layouts.

The part number 5220ED4004A must match the model’s parts listing. Do not assume that every visible flap near a drain pump is this valve, or that every LG dishwasher has the same filter assembly.

Which LG Dishwasher Models Use Check Valve 5220ED4004A?

Several LG families include compatible models, but the complete model number determines compatibility rather than the family name alone.

Use these families to narrow the lookup.

LG LDF
LG LDS
LG LDT
LG LDP
LG LSDF

Read the complete model from the door-edge tag before ordering. A listing for LG dishwasher check valve 5220ED4004A should identify your specific model, rather than simply naming LG.

How to Replace LG Dishwasher Check Valve 5220ED4004A Step by Step

Follow these steps to replace the valve on a matching LG dishwasher layout.

Phase 1: Cut Power and Water and Empty the Tub

Disconnect power and shut off the water supply.
Open the door.
Pull out and lift off the upper rack.

Phase 2: Remove the Lower Rack, Spray Arm, and Filter Assembly

Remove the lower rack.
Pull the lower spray arm upward.
Remove the Phillips screw and retainer at the water guide tube’s right base.
Release the tube’s top and rear clips with a flat screwdriver.
Turn the supply tube clockwise to detach its base.
Remove the filter screws and gently lift the assembly free.

Phase 3: Pull the Old Check Valve and Seat the New One

Release the drain-port cover with the flat screwdriver.
Remove its old valve.
Clear deposits from the port and cover.
Slide the new valve into the cover.
Refit the cover beneath the pump housing.

Phase 4: Reassemble and Run a Drain Test

Refit and screw down the filter assembly.
Reconnect the guide tube at its base, top, and rear.
Secure its retainer and Phillips screw.
Push the spray arm onto its holder and check free rotation.
Return both racks.
Close the door.
Restore water and power, then test drainage.

Should You Replace the Check Valve or the Drain Pump?

Valve replacement addresses confirmed backflow, while pump replacement addresses a confirmed pumping failure.

Compare the choices with the symptom.

Check valve: About $8 to $20 when the flap fails to seal and water returns after drain.
Drain pump: About $40 to $90 when the pump is faulty and cannot move water out.
Drain hose or high loop: Needs attention when blockage or routing causes the water problem.
Both valve and pump: Assess both on a pump older than eight years, but confirm the pump’s condition before adding it to the order.

A humming pump can have a mechanical obstruction, while a silent pump may have an electrical supply problem; neither symptom alone confirms that both components need replacement.

Why spend more before the cause is clear? A sound pump can remain in service when the problem is only a failed LG dishwasher check valve 5220ED4004A. Match the repair to the water’s behavior.

FAQ

Should I Cut Power and Water Before Replacing the Check Valve?

Yes, disconnect power and close the water supply before removing internal parts. Keep towels nearby and let the dishwasher cool after a recent hot cycle.

Can I Clean the Old Check Valve Instead of Replacing It?

Debris or deposits may prevent an intact flap from seating. A worn, damaged, or distorted flap needs replacement rather than more cleaning.

How Often Does a Check Valve Fail?

There is no fixed replacement schedule that suits every dishwasher. Backflow symptoms and the valve’s condition are more useful than age alone.

Clean Drain Water Every Cycle

A valve repair makes sense when the tub drains and dirty water comes back through a flap that will not seal. A model check helps you choose the correct part before opening the filter assembly.

Find the replacement check valve for your LG model after confirming 5220ED4004A fits, so used water stays out of the next wash.