Thermo King 914 724, Manual

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Electrical Maintenance (Rev. 1/99)
41
2. Attach a test lead to the B terminal and to the negative
terminal of the power source.
3. Attach a test lead to the 6 terminal and to the negative
terminal of the power source.
4. Connect a test light between the A terminal and the #1
terminal.
5. Attach a test lead to the 7 terminal and to the 5, 8, or 9
terminal. The terminal selected will determine the off
time of the test.
a. 5—4-hour selection Approx. 1 minute
b. 8—8-hour selection Approx. 2 minutes
c. 9—12-hour selection Approx. 3 minutes
4. Approximately 1 to 3 minutes after the timer termi-
nated defrost, the defrost cycle should reinitiate for
another brief period of time. This On-Off cycle should
repeat until the 12 circuit opens.
5. If the defrost timer fails to function properly, replace
the defrost timer.
Defrost Timer Bench Test
The defrost timer may be removed from the unit and bench
tested. Use the drawing to identify the terminals used to per-
form the bench test. Obtain a 12 volt battery or a 12 Vdc
power supply, some test leads, and a test light.
1. Attach a test lead to the test terminal and to the negative
terminal of the power source.
1. Test Light From Note 4 Above 6. Test Lead From Note 5 Above
2. Test Lead From Note 3 Above 7. Test Lead From Note 1 Above
3. Test Lead From Note 2 Above 8. Battery Positive Terminal
4. Battery Negative Terminal 9. Test Lead From Note 7 Above
5. Timer Test Terminal
Defrost Timer Bench Test
AGA311
1
2
3
4
5 6 7
8
9