Transfer switch will not switch back to utility

Automatic/Manual transfer switch repair, wiring & troubleshooting questions
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windboy14571
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Posts: 2
Joined: Sun Nov 03, 2019 3:39 pm

Sun Nov 03, 2019 4:14 pm

Quiet Source
27 KW 1 phase
2.4 L
Model QT02724ANAN
Serial 5083645
Built 08/04/08

Transfer switch
Model RTSE200A3
Serial5105498
120/240 volts

Our generator will not switch back to utility automatically. It was noticed first when the exercise cycle ran and the switch went to generator, but not back to utility when the exercise cycle was finished. Utility power was available the entire time. I have tried some different things (from other comments) and taken some readings.

What do I need to check next or what could be the problem?

Some readings from 23 & 194
Utility power available, on utility power
194 13.3 VDC
23 5.4 VDC
194 -23 8 VDC

If you pull the 23 wire off the terminal, the contacts in the cube cycle back and forth. Fwd to the front of the panel when wire 23 removed, aft towards the back of the panel when wire 23 touches the terminal block

trip utility, gen starts, switch goes to gen
194 13.3 VC
23 1 VDC
contact in cube are fwd

close breaker to utility, gen stops, but switch does not got to utility
193 13.3 VDC
23 5.4 VDC
contacts in cube are fwd

remove wire 23 from terminal, switch goes to utility
193 13.3 VDC
23 at wire 0
23 at terminal block 13.4 VDC

touch wire 23 to terminal block
wire in contact, contacts move aft
wire not in contact, contacts move fwd

If 23 wire is off the terminal and close the utility breaker, the switch will go to utility

If gen is running and you close the utility breaker, with the 23 wire off the terminal board and before generator shut down, then you put the 23 wire on the terminal board, the switch cycles to utility and then back to generator. Gen shuts down. It does not switch to utility. Take the 23 wire off the terminal board, the switch switches to utility.
Chris
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Location: Clawson, MI
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Sun Nov 03, 2019 4:38 pm

First things first, do NOT allow the generator to continue to exercise until you fix the problem!

If the unit is running a low speed test, you could burn up the transfer switch and/or the connected loads inside!

It sounds like the 23 wire is grounded somewhere. Basically anytime the switch is seeing generator voltage, it's instantly transferring, not good.

You'll have to find out where the 23 wire has rubbed through, or been hit with something grounding it.
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windboy14571
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Posts: 2
Joined: Sun Nov 03, 2019 3:39 pm

Wed Nov 06, 2019 11:23 am

Thanks. Will take a look at it.
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