This troubleshooting guide describes some of the issues that may be encountered with the operation/set-up of the automatic transfer switch. Troubleshooting beyond the scope of this guide should not be attempted by the installer. A licensed electrician must perform all internal troubleshooting.

The Utility Acceptable light does not come on when utility power is connected to the ATS.

1. Verify that the utility feed breaker is ON and that it is connected to the preferred source terminal lugs of the ATS labeled L1-L5

2. Verify the Utility Voltage is present and acceptable - 220-240VAC on L1-L5



3. With ALL POWER OFF, verify that the controller DIP switch settings for voltage and frequency are set for 220–240 V AC and 60 Hz. Locate and check DIP switch S2 actuator 2, and DIP S1 actuator 4. See Table D for voltage and frequency settings. Refer to page 8 of manual 381333-319F or below screenshot for reference.

S1 and S2 DIP switch location


S1 and S2 DIP switch settings for voltage and frequency


4. If above conditions are met and issue still occurs, With ALL POWER OFF, verify that the transfer switch harness is connected
properly to the controller (plug and receptacle tight).

5. With ALL POWER OFF, Unplug the harness from the controller and perform continuity check between L1  to P1-16 and L5 to P1-8. If there is no continuity it indicates a bad wire connection or crimp of wire to the terminal pin. Refer to 2 of 2 of elementary wiring diagram for the other plug and jack connections in this circuit.

6. If all the conditions above are good then it could be a bad control panel, order the appropriate part number K798923 for replacement. Contact Parts Department at 1-800-800-2726 dial 4 then option 2.

If unsure, please locate the serial number then contact Technical Support @ 1-800-800-2726 and press 3 or send an email to technicalsupport@ascopower.com