GE Zenith Controls 31■
ZTSCT / ZBTSCT Operation and Maintenance Manual (71R-5000A)
Troubleshooting and Diagnostics
HAZARDOUS VOLTAGES CAN CAUSE SEVERE INJURY OR DEATH.
These charts may indicate problems that require authorized GE Zenith service personnel.
Hazardous voltages may exist on termination plugs other than those that go into the Entelli-Switch 250.

Symptom Annunciation Possible Cause(s) Corrective Action

Engine does not START SOURCE 2
AVAILABLE
LED off
Engine start wires not
terminated properly Check engine start connections
Engine does not stop LCD Display -
“TD Engine Cool Down”
SOURCE 1 POSITION, and
SOURCE 1 and SOURCE 2
AVAILABLE LEDs on,
but U timer has timed out
U timing cycle not complete
Engine start wires not
terminated correctly
Generator in MANUAL
Check Utimer setting
Check Engine Start Connections
Place generator in AUTO
ATS will not transfer
to SOURCE 2 SOURCE 2AVAILABLE
LEDoff
None
SOURCE 2 voltage or frequency
not within acceptable parameters
Power supply connector unplugged
Check: Engine Start Connections,
GeneratorBreaker, Generator Output,
and Engine Control Switch
Plug in connector
ATS will not transfer
to SOURCE 1
SOURCE 1AVAILABLE
LEDoff
None
SOURCE 1 voltage or frequency
not within acceptable parameters
Power supply connector unplugged
Check utility and utility breakers
Plug in connector

General Troubleshooting

The following troubleshooting guide is used to recognize,
and determine basic faults. When using this guide, it will
ask several questions about the condition of the switch.
This guide will then list an order of the possible faults.
You will then look at the first suspected fault to determine
if it is the problem. If it is not a fault, you go to the
Generator is in OFFposition Investigate why Engine Control
Switch was turned off
LCD Display -
“S1 _ _ _ _ TD XFR S1>S2
Time Remaining _ _ _ _”
Wtiming cycle not complete Check WTimer setting
LCD Display -
“Diagnostic Code 001”
LCD Display -
“S1 OK
Time Remaining _ _ _ _
Bypass”
Limit switch or RT box
connector unplugged
T timing cycle not complete
Call Technical Services
Check TTimer setting
LCD Display -
“ATS Open
Time Remaining _ _ _ _”
DWtiming cycle not complete Check DWTimer setting
LCD Display -
“ATS Open
Time Remaining _ _ _ _”
TDtiming cycle not complete Check DT Timer setting
second suspected fault. If you go through all of the
suspected faults, or the chart instructs you to, call
a GE Zenith Representative for further assistance.
NOTE: When you use the troubleshooting charts,
the Annunciation column refers to the LED’s on
the control panel.
Table 4
DANGER