suddenly getting an ub error code on the display, washer won't drain.

Diagnosis

The UB (Unbalanced) error on the Samsung WA55CG7100AW occurs when the machine's internal sensors detect that the laundry load is not evenly distributed around the agitator or tub. During the transition from the wash cycle to the high-speed spin cycle, the tub rotates rapidly; if the weight is concentrated on one side, the resulting centrifugal force creates excessive vibration. To protect the suspension rods and the motor, the control board triggers the UB code and halts the spin process to prevent the machine from "walking" across the floor or damaging the outer tub.

This is often triggered by "clumping," where heavy items like towels, bedding, or a single heavy denim pair of jeans wrap around other clothes, creating a heavy mass on one side. However, it can also be caused by a "low-load" scenario, where a single heavy item (like a bath mat) sticks to one wall of the tub, creating an imbalance that the sensor cannot ignore. You can confirm this by observing the tub during the spin attempt; if you see the tub oscillating violently before the error pops up, it is a mechanical balance issue rather than a sensor failure.

How to Fix It

To resolve the UB error and force the machine to complete the drain and spin cycle, follow these precise steps:

1. Press the Start/Pause button to halt the current cycle immediately.
2. Open the lid and manually reach into the tub. Locate the area where the clothes are bunched or piled high on one side.
3. Physically pull the laundry apart and redistribute it evenly in a ring around the agitator. If you have a single heavy item, move it to the opposite side of where it was originally resting.
4. Ensure no clothing items are caught between the inner tub and the outer casing.
5. Close the lid firmly. You should hear a click indicating the lid switch is engaged.
6. Press the Start/Pause button again. The machine will now perform a "sensing" phase to check the balance before attempting the high-speed spin.
7. If the machine still won't spin, manually select the Spin Only cycle from the dial, set the spin speed to "Medium" or "Low" to test stability, and press Start.

If That Didn't Work

If redistributing the load does not clear the UB code, investigate these mechanical possibilities:

• Level the Machine Feet: Place a bubble level on the top rim of the washer. If the bubble isn't centered, rotate the adjustable leveling legs at the bottom front of the machine. Turn the legs clockwise to raise the machine and counter-clockwise to lower it. Ensure all four feet are firmly touching the floor; if one is hovering even 1/8th of an inch, the machine will vibrate and trigger a UB error.
• Check for Suspension Rod Failure: Open the lid and push down firmly on the tub. If the tub bounces up and down several times like a spring rather than returning to center immediately, one or more of the four suspension rods have lost their tension. You will need to replace the suspension rod assembly (typically sold as a set of 4) to restore the tub's stability.
• Clear the Drain Pump Filter: While UB is a balance error, a partial clog in the drain hose or pump can cause the tub to retain too much water, making the load heavier and more prone to imbalance. Inspect the drain hose for kinks and ensure the standpipe is not clogged, allowing water to flow freely.
• Reset the Control Board: Unplug the washer from the 120V wall outlet for exactly 10 minutes. This clears the temporary memory of the control board and resets the sensor calibration. Plug it back in and attempt a "Spin Only" cycle with an empty tub to see if the error persists.

Heads Up

Keep these maintenance tips in mind to prevent future UB errors:

• Avoid "Single Item" Loads: Never wash a single heavy item (like one heavy bath rug) alone. Always add a few towels or smaller items to balance the weight distribution.
• Don't Overload: Fill the tub no more than 3/4 full. Overstuffing prevents the clothes from moving freely, making it impossible for the machine to balance the load during the spin cycle.
• Check the Floor Surface: If your washer is on a vinyl or laminate floor, it may shift over time. Periodically check that the leveling legs haven't vibrated loose.
• Use Heavy Duty Racks: If the machine is on a wooden floor that flexes, consider a reinforced laundry pedestal or a plywood base to provide a rigid surface, which reduces the likelihood of vibration-induced UB codes.