Fisher & Paykel Dishwasher Error Code U3

The U3 error code on a Fisher & Paykel DishDrawer indicates that the tub filled with water too quickly during the fill cycle, meaning the time to reach the target water level was shorter than expected. This points to a specific problem: water was already sitting in the tub at the start of the fill cycle, which means the previous drain cycle did not complete successfully. The control system monitors fill time as a way to detect residual water, and when that time falls below the minimum threshold, it triggers U3 and halts operation to prevent overflow or mechanical damage.

The most common root cause is a failure in the drain system. A blocked drain pump or clogged drain impeller will prevent the tub from emptying fully between cycles. A kinked or obstructed drain hose can produce the same result. Beyond physical blockages, the spray arm or rotor may not be turning freely, which can disrupt wash and drain sequencing. In some cases, motor electronics failure can prevent the drain pump from operating correctly even when there is no physical obstruction present.

One additional and often overlooked cause involves the machine's pressure setting. Fisher & Paykel DishDrawers have a low pressure (LP) configuration option intended for installations with lower water supply pressure. If the machine is set to LP but is connected to a high-pressure water supply, the tub will fill faster than the control board anticipates, producing a fill time that is too short and triggering U3. On the mechanical side, if the locknut on the filter plate is not locked correctly, the filter assembly can shift and interfere with normal drain or fill behavior.