I get several calls a week for poor washing complaints in newer dishwashers. When I go out on these service calls, I often find that there's nothing wrong with the dishwasher from a repair standpoint.
Most people don't have a clue about how dishwashers work. Invariably, when I'm on a dishwasher service call, I find people making one or more of three common mistakes that almost all dishwasher owners make. As a result, they have washability problems: dishes don't get clean, film left on glassware and dishes, or glassware gets etched and cloudy.
So before we get into the Big Three Deadly Dishwasher Mistakes, let's do a quick overview of how dishwashers are *designed* to work.
Dishwashers need three things to do their job:
- Mechanical action: water sprayed from the spray arms,
- Thermal action: water heated to 120-125 deg. F to activate detergent,
- Chemical action: good quality, fresh, dry POWDERED detergent matched to the amount of water hardness, and the use of rinse-aid.
If the dishwasher itself is operating within specs (conditions 1 and 2 above are satisfied) then almost all dishwasher washability complaints come down to the third condition: bad chemistry.
Chemistry problems will involve one or more of these factors:
- Rinse Aid
- Water Hardness