Here in Tech Support at www.transferswitch4less.com We get to help our customers solve operational issues with their Automatic Transfer Switch and generator installations.
Below are the typical symptoms that are reported and how to troubleshoot them.
Generator will not start during a power outage
An Automatic Transfer Switch communicates with the generators controller using a industry standard two wire system. When purchased power is interrupted there is a relay in the Automatic Transfer Switch that drops out, shorting the two wires from the generators controller together. This causes the generator to start and run.
Troubleshooting this kind of problem is as easy as removing the two wires coming from the generators controller and shorting them together. This will cause the generator to start and run. If the generator does not start and run then the problem is in the generator. If the generator starts then the problem is in the Automatic Transfer Switch. The only part in an ASCO automatic Transfer Switch that performs this function is the control board, which is a field replaceable unit that we sell in our parts department.
Generator will not stop running
If the generator will not stop running the first thing to do is to check the Automatic Transfer Switch and determine if it is recognizing purchased power as acceptable. This is as easy as looking at the control panel on the Automatic Transfer Switch.
If the utility power is not being recognized as acceptable,check the phase to phase voltage. It needs to be within 5% of the nominal value plus or minus. Nominal values are 208 volts, 240 volts, and 480 volts in the United States. If the utility voltage is within 5% of the nominal value then the Automatic transfer Switch has a control board failure. This is most often caused by Transient Surges due to lightning strikes.
Prior to replacing the control board carefully inspect the harness and the TS unit on the Automatic Transfer Switch. If you see or smell any burning in these areas the easiest solution will be to replace the entire switch. Be very careful here, as we have seen many good electricians start replacing burned parts only to have a unseen failure location cause expensive replacement parts like control boards to burn up themselves.
If the Automatic Transfer Switch is recognizing and is supplying purchased power to the load as indicated on the control panel, then remove the two wires that connect the generator controller to the Automatic transfer Switch. If the generator stops then the Automatic Transfer Switch controller is defective, if the generator does not stop then the problem is in the generator.
Automatic Transfer Switch will not Transfer to Generator Power
The first step to troubleshoot this problem is to determine if the Automatic Transfer Switch is recognizing the generators power as acceptable. This is as easy as looking at the control panel on the Automatic Transfer Switch.
If the Automatic Transfer Switch is not recognizing the generators power as acceptable then check the phase to phase voltage at the emergency lugs on theAutomatic Transfer Switch TS unit. This voltage needs to be within 5% plus or minus. If this is acceptable then check the frequency using a digital voltmeter, not the on the generator. If the generators frequency is not plus or minus 3.0 hertz then the Automatic Transfer Switch will not recognize the generator power as acceptable and will not switch the load to it.
I hope this article was helpful. If you need further assistance please call one of our experts at www.transferswitch4less.com We are happy to help troubleshoot and have in stock repair parts and complete switch assemblies to get you back up and running.