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5.23
Tracing oven temperature sensor faults
Refer to Technical Overview Section 2.15
PROCEDURE:
Enter Technician Mode diagnostics to view cavity temperature reading.
(Refer to Diagnostics Section 4.3)
Record cavity temperature reading then substitute the oven temperature sensor with a
new sensor.
(Refer to Servicing Instructions Section 7.12)
Record cavity temperature reading from new sensor.
If there is a significant difference between the two temperature readings (>10
°
F or >5
°
C)
then leave the new sensor in.
If the two temperature readings are similar (
±
10
°
F) (
±
5
°
C) check temperature sensor
wiring connectors and connection to power module.
If connections are good then it is likely that temperature sensor is not faulty.
Refit the original temperature sensor.
(Refer to Servicing Instructions Section 7.12).
If the fault persists, then test power module by substituting 1000 ohm 5% resistor across
pins 1&2 on the “Sensors” connector.
(Refer to Technical Overview Section 2.24 for pin numbering)
The temperature display should read 32°F + 10°F (0°C+ 5°C).
Replace power module if the displayed reading is incorrect.
(Refer to Servicing Instructions Section 7.9)
5.24
Tracing thermal limiter faults
Refer to Technical Overview Section 2.27
Note: In the event of a thermal limiter tripping, it is important that the cause be
found and rectified.
PROCEDURE:
Do a continuity test between L2 and the terminal block side of the isolating relay.
Note:
Isolating relay only used in USA and Canada.
Note:
To do a quick check for a tripped microtemp limiter test for 12
VAC
on 2 way
connector into power module from transformer.
(Refer to Technical Overview Section 2.24)
If there is no continuity then this indicates a tripped thermal limiter.
To locate the tripped thermal limiter check for continuity across the limiter contacts.
