Dishwasher Operation and Repair
Dishwasher water systems, spray arms, detergent dispensers, heating elements, drain pumps, air gaps, and troubleshooting common faults.
- Explain the function of the spray arm and water circulation system
- Describe the role of the heating element, detergent dispenser, and drain pump
- Identify the purpose of the air gap in dishwasher drain systems
- Diagnose common dishwasher faults including fill and drain problems
- Explain causes of white residue on dishes
Leçon 1
Water Inlet, Spray Arms, and Circulation
How a Dishwasher Cleans
A dishwasher cleans dishes by spraying hot water mixed with detergent at high pressure across the dish surfaces. The wash system circulates water continuously during the wash and rinse cycles rather than using a fresh supply for every moment of the cycle.
The Spray Arm
The purpose of the spray arm in a dishwasher is to distribute water over dishes for cleaning. Spray arms are typically found on the bottom and top of the wash compartment (and sometimes a third one for the upper rack). They rotate freely, propelled by the force of water ejecting from angled holes along their length.
Water Fill Problems
When a dishwasher does not fill with water, the cause is a faulty water inlet valve or closed supply. Before replacing the valve, check that the water supply shutoff is open and the supply line is not kinked. Then test the valve solenoid for proper resistance and verify it receives voltage from the control.
Float Switch
Most dishwashers have a float switch at the bottom of the tub. If the float sticks in the up position, the control thinks the tub is full and will not allow the water inlet valve to open. Check the float for debris before condemning the inlet valve.
The spray arm distributes water over dishes for cleaning. A dishwasher that does not fill typically has a faulty water inlet valve or closed supply. Always verify supply and float switch before replacing the valve.