Microwave Gas (Humidity) Sensor; Microwave Interlocks And Monitor - GE ZEK957 Series Technical Service Manual

Microwave Gas (Humidity) Sensor

The microwave must be removed from the oven to
service the gas sensor.
A gas sensor is used in AUTO COOK mode to
monitor increasing humidity (steam) and hydrocar-
bons (food odors) during cooking. When vapor
increases in the oven due to cooking, the resis-
tance of the sensor changes. This information is
received by the PCB, which adjusts the cooking
time to various types and amounts of food.
The gas sensor is located on the outer left side of
the oven cavity by the cavity exhaust.
Sensor Test
Caution: Do not attempt to check sensor with
ohmmeter. Sensor damage will occur. Only
heater terminals (H) can be checked with ohmme-
ter (30Ω).
1. Place 1/3 cup tap water in microwave.
2. Press the popcorn pad.
3. After 1-2 minutes, the control should beep and
the display should begin a countdown.
4. Press CLEAR/OFF pad.
a. If sensor fails test, go to step 5.
b. If sensor passes test, sensor is OK.
5. Press and hold the 7 and 8 number pads at the
same time.
6. Observe the diagnostic number in the display.
• 15 to 184 - sensor OK.
• 185 or higher - sensor failed open, sensor
unplugged, sensor circuit open, or faulty
PCB.
• Less than 15 - shorted sensor or faulty PCB.

Microwave Interlocks and Monitor

Obtain access to the interlock and monitor
switches by placing the control panel in the service
position.
The primary interlock, interlock monitor, and door
sensing switches are mounted to a plastic latch
board on the right side of the cavity. The switches
are as follows:
• Primary Interlock
This switch interrupts the circuit to all compo
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