Troubleshooting, Symptom Possible Cause Corrective Action

Troubleshooting

DANGER

HAZARDOUS VOLTAGE

(Can Cause Severe Injury or Death)

Turn OFF all power before installation, adjustment, or removal of transfer switch or any of its components.

Service must be performed by qualified personnel.

Symptom	Possible Cause	Corrective Action
S1 or S2 Available LED not lit	Sources either fully or partially unacceptable	Check for under voltage
	S1 or S2 breakers open	Check for missing phase (s)
		Check for under frequency

ATS will not retransfer Load	T - Timer has not expired
back to Utility	Automatic Exerciser is in process
	S1 Utility fully or partially unacceptable

ATS does not transfer Load to S2	S2 Generator fully or partially unacceptable	Set motor-saver to dropout below
(generator)	Motor loads on system creating enough back-	ATS Fail setpoint
	EMF to keep missing phase from falling below
	Fail setpoint.

S2 Generator will not start	X1 or X2 not connected	Check Generator Start wiring

S2 Generator will not shut down	U - Timer not expired	Wait for U timer to expire
	Automatic Exerciser in process

All LEDs off	Keypad connector unplugged at Controller
	Both source breakers open

ATS will not transfer in-phase	In-Phase monitor not on	Turn on In-Phase monitor
	Frequency difference between S1 and	Adjust Generator governor to hold
	S2 greater than 2Hz.	freqency closer to Utility

ATS will not retain a	Battery dead or missing	Replace battery with a fresh industrial
Set Automatic Exerciser		grade Alkaline battery

Timer/In-Phase LED constantly on	Both sources locked in frequency or one	Turn In-Phase monitor off
	source greater than 20° out of phase

S1 and S2 LEDs Blinking	Phase Rotation Mis-match between sources	Rewire sources to be same rotation

S1 Position LED Blinking	SN limit switch bad or intermittent	Check connection or SN limit switch

S2 Position LED Blinking	SE Limit switch bad or intermittent	Check connection or SE limit switch

Both S1 and S2 Positioin	Solenoid bad or disconnected	Requires CANCEL key to clear -
LEDs Blinking	ATS contactor in mid-position	check Solenoid
		Requires CANCEL key to clear -
		Check both limit switches

		Table 9

■ GE Zenith Controls

ZTX Operation and Maintenance Manual (72R-1000)

15 ■