Service Manual

3-16
n
18” & 24” ADA Built-In Dishwashers
TESTING
For Service Technician Use Only
Drain Pump
The drain pump is located under the tub and operates on 120
VAC. It is energized for the rst 60 seconds of a new cycle and
90 seconds aer the wash pump shuts down to remove any
water in the dishwasher sump. The drain pump forces water
out of the drain line. A check valve apper on the drain pump
prevents the dirty water from reentering the sump.
This test will check the wiring to the drain pump and the drain
pump itself. The following items are part of the drain pump
circuit.
n Harness/Connecon
n Drain Pump
n Control Board
Test Procedure
1. Verify that drain hose or drain path is not obstructed.
Check for blockage from sump check valve to customer’s
plumbing. Check for plugged hoses, plugged garbage
disposal, or disposal plug not knocked out. Repair as
needed.
2. Check the drain pump and electrical connecons by
performing “Service Mode Test” on page 2-3. The
following steps assume that this step was unsuccessful.
3. Unplug dishwasher or disconnect power.
4. Remove access panel. Remove control board cover to
access control board.
5. Lay the dishwasher on its back. Use a small at-blade
screwdriver to unclip snaps around the drip-pan. Remove
drip-pan/oat switch to access under tub components.
6. Unplug connector CON2 from control board.
7. Check the drain motor—using an ohmmeter, measure the
resistance between CON2-1 and CON1-1.
¾ If the resistance is between 25-35 ohms, the drain
motor and harness are good. Go to step 8.
¾ If far outside the range, replace the drain pump.
¾ If an open circuit is detected, check connecons and
harness connuity between control and drain pump. If
good, replace the drain pump.
8. Reconnect CON2 to control board.
9. Set voltmeter to AC. Connect red lead to CON2-1 and
black lead to and CON1-1 on the control board. Plug in
dishwasher or reconnect power.
10. Start the Service Mode Test and at step-5 measure for AC
out of the control between CON2-1 and CON1-1.
IMPORTANT: The Drain Motor must be connected to the
control board to measure voltage accurately!
¾ If no AC voltage is measured, replace the control board
and retest.
¾ If 120 VAC is measured and drain pump is running, go
to step 11.
11. Unplug dishwasher or disconnect power.
12. Reassemble all parts and panels.
13. Plug in dishwasher or reconnect power and run Service
Mode to verify repair.
DANGER
Electrical Shock Hazard
Only authorized technicians should perform
diagnostic voltage measurements.
After performing voltage measurements,
disconnect power before servicing.
Failure to follow these instructions can result in
death or electrical shock.
STRIP CIRCUIT - DRAIN PUMP
Figure 2 - Drain Pump Strip Circuit
CONTROL BOARD
DRAIN PUMP
DRAIN PUMP
L1
CON1-2
DRAIN PUMP RELAY
(L)
RD
RD
BR
25 - 35 Ω
RD
RD
THERMAL
CONTROL BOARD
N
CON1-1
CON1-1
(N)(N)
BU
P
CON2-1
(PS)
PRESSURE
SWITCH (120 VAC)
BR
RD
Normally
Open
120 VAC
Figure 1 - Drain Pump
Drain Pump
Drain Hose
Sump
Thermistor