Water Sensing With Owi Sensor - KitchenAid KMTM704E Series Technical Education

-6 -1
-6 -1 -5 -6
P8 P9
RD V
Unplug dishwasher or disconnect power.
I
Perform resistance checks. To check resistance of a component,
I
disconnect harness leads first.
Electrical Shock Hazard
Only authorized technicians should perform
(To Wash Motor,
diagnostic voltage measurements.
Vent, and Triac Loads)
After performing voltage measurements,
N.O.
disconnect power before servicing.
Failure to follow these instructions can result in K2
death or electrical shock.
Pilot (L1) Relay
Water Sensing with the OWI Sensor
This test will check the wiring to the OWI (Optical Water
Micro Pin Micro Pin
Indicator), which incorporates the temperature thermistor and
the foam & turbidity sensor. The following items are part of
the water sensing circuit.
Electronic Control
n Harness/Connection
n OWI Sensor
n Control Board
Run
Winding
Test Procedure
3Ω - 7Ω
1. Check the operation of the OWI Sensor in the Service
TURQ
Diagnostic Cycle.
(LBU)
V
2. Unplug dishwasher or disconnect power.
P5-2
Pin 2
3. Remove toe and access panels to access control board.
AUX
4. Disconnect P12 from the Control Board.
Winding
6Ω - 10Ω
5. Using an ohmmeter, measure resistance between P12,
pins 1 and 3. The following table provides approximate
Motor and Capacitor
room and hot water temperatures and their associated
(Wash Pump)
resistance values.
120V, 60 Hz, 190W typical
Strip Circuit – Water Sensing
N
WH
P4-1
Float
Float Switch
-1 -3 -5 -1 -2 -4 -6
P10 P11
For Service Technician Use Only
BR RD
DANGER
(To Heater)
N.O.
K3
Heater (L1) Relay
Micro Pin
TURQ
(LBU)
P5-1
Pin 3
Motor N Relay
CAP
Y
Y
(Also see Door
23.5 µF
Switch Circuit)
Electronic Control
YL
Electronic P12-6
Control YL
P12-5
YL
P12-4
YL
P12-3
YL
P12-2
YL
P12-1
P12 (Wide Out)
P13
-1 -3
P12
YL
NOTE: All thermistor resistance measurements must be
made while dishwasher is unplugged or disconnected
from power and connector P12 removed from control.
¾ If the thermistor resistance is OK , the thermistor is
¾ If the thermistor resistance does not agree with the
(To Wash Motor)
¾ If an open circuit is detected, check connections and
N.O.
K4
Motor (N) Relay
6. Using an ohmmeter, check P12 -1 to cabinet ground and
P12-3 to cabinet ground.
¾ If no short is indicated, go to step 7.
¾ If either pin indicates continuity to ground (short),
Micro Pin
7. Reconnect P12 to control board.
8. Test for 5 VDC—With a voltmeter set to DC, connect the
black lead to P12-2 and the red lead to P12-3.
9. Plug in dishwasher or reconnect power.
10. Start the Diagnostic Cycle and at the proper interval
measure for 5 VDC out of the control between P12-2 and
P12-3.
¾ If 5 VDC is measured the control is functioning, go to
Sense Resistor
or Jumper
¾ If no DC voltage is measured, replace the control board
0Ω
N.O.
WH
11. Unplug dishwasher or disconnect power.
P4-1
K4
12. Reassemble all parts and panels.
13. Plug in dishwasher or reconnect power and run Diagnostic
Cycle to verify repair.
Pin 1
Turbidity Drive
Pin 2
Foam Drive
Pin 3
OPT Sig
Pin 4
VCC
Pin 5
Ref
Pin 6
NTC
Measure NTC resistance at P12-1 and
P12-3 connector disconnected from control.
KitchenAid 2015 Microfiltration Dishwashers
TEMP °F (°C)
77° F (25° C)
140° F (60° C)
good. Go to step 6.
table, replace the OWI Sensor.
harness continuity between control and OWI If good,
replace the OWI Sensor.
repair or replace wiring harness and retest.
N
step 11.
and retest.
O.W.I. Sensor
Temperature: NTC Thermistor
46KΩ - 52KΩ at 77°F (25°C)
11KΩ - 13KΩ at 140°F (60°C)
TESTING
RES RANGE k ohms
46 – 52k ohms
11 – 13k ohms
n
6-11