The Alternating Wash System - Frigidaire Fully Integrated Direct FeedModel Dishwashers Service Manual

On the underside of the filter is a soil director which
directs the loosened food particles to the lower left
side of the sump to a stainless steel food macerator
used to pulverize the soil so it can pass through the
drain hose. See Figure 5
Figure 5
The remaining parts in the wash system are the
sump assembly that acts as a reservoir for clean
water being supplied to the wash pump and the
delivery tube to supply water to the upper two spray
arms.

The Alternating Wash System

This wash system is designed to spray from only one
arm or one set of arms at a time. The advantage of
this is that it reduces the amount of water needed in
the tub. The way this system operates is explained
as follows.
Alternating the spray is achieved with a check ball
moving between two holes in the sump. One hole is
located in the rear of the sump used to supply water
to the upper two spray arms; the second is located
out the top of the volute cover onto which is mounted
the lower spray arm.
Bypass opening
Ball covering back hole
Figure 6
The check ball rests at the end of a ramp molded
into the sump partially blocking the rear hole. As
water under pressure enters the volute cover, the
check ball is held tightly into the rear hole restricting
water flow from this opening. Water can only leave
the remaining hole from the top of the volute cover
into the lower spray arm. See Figure 7
Opening to
lower spray
arm
The force of the water entering and leaving the arm
causes it to turn by the positioning of the hole in the
spray arm. The rear hole which is molded in the
sump has a small section removed above where the
check ball sets, this section allows a small amount of
water to by-pass the check ball and enter the delivery
tube mounted up the out side rear of the tub. Water
by-passing the check ball will fill the delivery tube at a
rate of approximately four inches a second. This
water will be used to change the spray from bottom
to the upper two spray arms. All wash and rinse
cycles will start by spraying from the lower wash arm.
Changing spray from bottom to upper spray arms is
accomplished with the control stopping the wash
pump for not more then .6 of a second. This pause
removes water pressure from the rear of the check
ball, water that had accumulated in the delivery tube
now reenter the sump, which moves the check ball
away from the hole and up the ramp.
9
Figure 7
Volute cover
Figure 8