Viking Repair Bothell, WA home page (206) 202-2799

Dishwasher Parts, in the order water meets them

Circulation Pump and Spray Arms

Drives the wash water up through the spray arms and onto every rack.

Water path through a built-in dishwasher (side section) Water gathers in the sump. The circulation pump drives it up to the lower and upper spray arms; the drain pump pushes it out through a check valve and up a drain hose that loops high under the counter before dropping to the sink drain. The door hangs on a pivot at its foot, held by a spring. 1 2 3

The wash run picked out in rust: water drawn from the sump by the circulation pump and driven up to the lower spray arm and, through a tube, the upper one.

  1. Circulation pump and spray arms
  2. Drain pump and check valve
  3. Door hinges, springs and panel mount

Does

The circulation pump sits by the sump, pulls the wash water back through the filters and pushes it under pressure into the spray arms. The lower arm turns beneath the bottom rack; a feed tube carries water up to the arm under the upper rack. Spinning, the arms throw that water across the dishes again and again through the cycle.

Fails like

  • Dishes on the top rack come out gritty while the bottom rack is clean.
  • A thin wash on every rack, the motor humming but little sound of water striking the door.
  • An arm that will not turn, or a grinding note from under the tub when something hard reaches the pump.

Replaced when

A pump whose motor has seized or burnt out is replaced. A cracked arm or a split feed tube is replaced by itself. Jets clogged with debris or scale are cleared, and the arm goes back on.

Dishwasher standing out of its cabinet opening with the base panel off, the pump and sump assembly, drain hose and wiring exposed, and a wrench on a towel.

The supply behind the wash

The pump can only move the water the house lets in. The DFUD042 recommends water at 120°F or more at the dishwasher, while noting it still performs on cold, and lists an inlet range of 18 to 176 psi. The VDWU524 accepts 4.35 to 145 psi and heats its own water with an 1100 W element. A supply valve left part-closed after a remodel can leave the fill short, and the arms then have less to spray.

On the visit

We check that the pump runs and builds pressure, that nothing is lodged at its intake, that each arm spins freely with every jet open, and that the feed tube to the upper arm is seated and whole. Grit on the top rack alone sends us to that tube and the upper arm before the pump.

First, at home

With the machine switched off, lift the filters out as your use and care guide shows and rinse them. Make sure no pan handle or tall board hangs into an arm’s path, then turn each arm by hand; it should spin without catching.