ES50 VOLT Transfer Switch with Onan 12.5HDCAB115006A Transfer Switch-No Power to Interior 50-amp Panel

[Lee Smith]

2004 Monaco Signature Conquest
It appears to me my ESCO transfer switch is not working. What appears to be the connector switch to send generator power to the interior 50-amp panel does not close when the generator is running, and shore power not connected. The transfer switch connections for the generator have 118 volts between Hot Leg L4 (black) and Neutral Leg L5(white). Also has 118 volts between Hot Leg L4 and common ground bar. There is no voltage between L6(red) and L5(white) or L6 and common ground.

With generator off and connected to shore power the 50-amp interior panel functions fine. The surge suppressor works fine.

I am not sure, but since the Coach only needs/uses 110 power, the L5 leg is not needed as that would generate 220 power across L4 and L6.

Is there a way to test the transfer switch? Generator power incoming is at 118 volts on L4 but nothing out the other side as connector does not appear to close.

Any ideas are greatly appreciated.

Here are pictures:

Connections From Generator To Transfer Switch

Onan Generator Specifications

Transfer Switch Lable

Transfer Switch Wiring (Shore and Generator)

Transfer Switch Contact Switch -Open When On Generator Power With Shore Power Not Connected

Thank you for your help,

Edited May 23, 2022 by Lee Smith
Spelling

[Ivan K]

Do I understand it right that you are only getting one hot line from the 12.5k generator? It should provide two 110V lines, 220V between them just like shore 50 Amp. If so, I would check for output of the generator under the little cover in front passenger side of the enclosure. Also, is the red wire in your last picture making good contact?

[Lee Smith]

Okay, that helps as I was not sure of the two hot sides. The red wire was making a good connection at the transfer switch.

Good idea to check the output at the generator.

Thank you.

[Tom Cherry]

51 minutes ago, Lee Smith said:

2004 Monaco Signature Conquest
It appears to me my ESCO transfer switch is not working. What appears to be the connector switch to send generator power to the interior 50-amp panel does not close when the generator is running, and shore power not connected. The transfer switch connections for the generator have 118 volts between Hot Leg L4 (black) and Neutral Leg L5(white). Also has 118 volts between Hot Leg L4 and common ground bar. There is no voltage between L6(red) and L5(white) or L6 and common ground.

With generator off and connected to shore power the 50-amp interior panel functions fine. The surge suppressor works fine.

I am not sure, but since the Coach only needs/uses 110 power, the L5 leg is not needed as that would generate 220 power across L4 and L6.

Is there a way to test the transfer switch? Generator power incoming is at 118 volts on L4 but nothing out the other side as connector does not appear to close.

Any ideas are greatly appreciated.

Here are pictures:

Connections From Generator To Transfer Switch

Onan Generator Specifications

Transfer Switch Lable

Transfer Switch Wiring (Shore and Generator)

Transfer Switch Contact Switch -Open When On Generator Power With Shore Power Not Connected

Thank you for your help,

http://s39678d0cbebd4194.jimcontent.com/download/version/1363344954/module/6559756754/name/ES50VOLTSURGETrblshting_repair_060607.pdf
 

Here is the manual for the ATS.  I think it is the “built like a masonry outhouse” ATS that our late founder, Col. D loved.

Followup on Ivan’s post, which just popped up.

You should have the following voltages….from the Genny….  

L4 - L5 > 115 VAC (or within that range and 118 is fine)

L6 - L5 > 115 VAC

L4 - L5 >  230 VAC.

If you measure either L4 or L6 to the white common buss….or to the Green Gound terminal, you should have 115 VAC..

Yes, your MH does NOT use 230 Volts, but your Genny, as well as the Shore Pedestal, are wired the same.  You COULD have, if required, a 230 VAC circuit….

Bottom line, if you don’t have the voltages above, which I believe you stated, then you have lost one “Leg” or L6 side of your Genny….and this is NOT an ATS issue….

NOW….that entails a lot more trouble shooting.  Things I remember as the larger (10 & 12.5 KW) are different from my smaller 8KW.

I would, with the Genny OFF, check the circuit breaker on the Genny.  Maybe even cycle it a few times.  Then, restart the Genny and use your manual (or download one) and look for any flashing trouble codes….then look them up.  This is fairly simple.  

If cycling the breaker doesn’t get your voltage to the L6 terminal or Red Wire….then you need to either start digging or get a tech.  There were two major issues, I believe, with the larger ones.  

Brushes.  You need to put a high demand (not overload) each side of the Genny (red and black) for maybe half an hour….this keeps the brushes polished or burnished and is a common issue.  You run the AC and or use space heaters….but you have to know which outlets are on each leg.  And that is tricky unless you understand the internal circuits downstream of the main breaker.

Control Boards.  The larger control boards have been troublesome….many mobile Genny techs carry spares, both new and rebuilt (FlightSystem(or s).com is a well known rebuilder of the boards.  Usually, the issue is Moisture and results in starting issues….

Do what you can within your electrical knowledge and skill set….but your ATS appears to be OK.

 

[96 EVO]

I burned up the 'Time Delay Board' on my ESCO transfer switch. Mentioned it at the end of this thread...

 

[Lee Smith]

Thank you for all of that knowledge.
I will do a little more checking but it does look like tech time.

[Chuck B 2004 Windsor]

58 minutes ago, Tom Cherry said:

http://s39678d0cbebd4194.jimcontent.com/download/version/1363344954/module/6559756754/name/ES50VOLTSURGETrblshting_repair_060607.pdf
 

Here is the manual for the ATS.  I think it is the “built like a masonry outhouse” ATS that our late founder, Col. D loved.

Followup on Ivan’s post, which just popped up.

You should have the following voltages….from the Genny….  

L4 - L5 > 115 VAC (or within that range and 118 is fine)

L6 - L5 > 115 VAC

L4 - L5 >  230 VAC.

If you measure either L4 or L6 to the white common buss….or to the Green Gound terminal, you should have 115 VAC..

Yes, your MH does NOT use 230 Volts, but your Genny, as well as the Shore Pedestal, are wired the same.  You COULD have, if required, a 230 VAC circuit….

Bottom line, if you don’t have the voltages above, which I believe you stated, then you have lost one “Leg” or L6 side of your Genny….and this is NOT an ATS issue….

NOW….that entails a lot more trouble shooting.  Things I remember as the larger (10 & 12.5 KW) are different from my smaller 8KW.

I would, with the Genny OFF, check the circuit breaker on the Genny.  Maybe even cycle it a few times.  Then, restart the Genny and use your manual (or download one) and look for any flashing trouble codes….then look them up.  This is fairly simple.  

If cycling the breaker doesn’t get your voltage to the L6 terminal or Red Wire….then you need to either start digging or get a tech.  There were two major issues, I believe, with the larger ones.  

Brushes.  You need to put a high demand (not overload) each side of the Genny (red and black) for maybe half an hour….this keeps the brushes polished or burnished and is a common issue.  You run the AC and or use space heaters….but you have to know which outlets are on each leg.  And that is tricky unless you understand the internal circuits downstream of the main breaker.

Control Boards.  The larger control boards have been troublesome….many mobile Genny techs carry spares, both new and rebuilt (FlightSystem(or s).com is a well known rebuilder of the boards.  Usually, the issue is Moisture and results in starting issues….

Do what you can within your electrical knowledge and skill set….but your ATS appears to be OK.

 

Keep in mind that the 10.0 and 12.5 generators are true generators.  The 7.5 and 8.0 are inverters.

2 hours ago, Lee Smith said:

2004 Monaco Signature Conquest
It appears to me my ESCO transfer switch is not working. What appears to be the connector switch to send generator power to the interior 50-amp panel does not close when the generator is running, and shore power not connected. The transfer switch connections for the generator have 118 volts between Hot Leg L4 (black) and Neutral Leg L5(white). Also has 118 volts between Hot Leg L4 and common ground bar. There is no voltage between L6(red) and L5(white) or L6 and common ground.

With generator off and connected to shore power the 50-amp interior panel functions fine. The surge suppressor works fine.

I am not sure, but since the Coach only needs/uses 110 power, the L5 leg is not needed as that would generate 220 power across L4 and L6.

Is there a way to test the transfer switch? Generator power incoming is at 118 volts on L4 but nothing out the other side as connector does not appear to close.

Any ideas are greatly appreciated.

Here are pictures:

Connections From Generator To Transfer Switch

Onan Generator Specifications

Transfer Switch Lable

Transfer Switch Wiring (Shore and Generator)

Transfer Switch Contact Switch -Open When On Generator Power With Shore Power Not Connected

Thank you for your help,

It would help if your picture showed all the inside of the transfer switch.  If one would as for a picture of the front of a coach, a picture of the head lights would not help.

[Larry Laursen]

I had my ESCO ATS fail on my unit last year.  The wire coming from the control circuit board fell off and wouldn't close the relay on the generator side.  The control wires are hard access, and I couldn't reconnect the wire without tearing the entire unit apart.  It was still under warranty, so I got a new one.  I temporally jumpered the wire to the main control to use on the road.  I don't recommend this as it took the delay out of system.

[Lee Smith]

Problem Solved.
Thank you to all who provided so very much detailed and on target information that allowed me to troubleshoot the "Transfer Switch" and "Surge Suppressor" which enabled me to eliminate both as the problem. 

The solution was on page 12-6 of the Onan HDCAB Service Manual as follows:
NO AC POWER WHEN GENSET IS RUNNING
3. Check voltage at genset AC output terminal block TB2 when the genset is running. If there is approximately
120 VAC across TB2-1 and TB2-3 and across TB2-2 and TB2-3, repair or reconnect the wiring
between the genset and the main vehicle distribution panel. If there is no voltage, go to Step 4.
4. Check for proper AC harness connections and repair as necessary (p. A-3).

I removed a small generator topside panel to gain access to the AC output terminal block TB2 and check the voltage readings. The voltage readings were exactly what I had measured at the transfer switch terminal block.  Leg 2 (white genset to red harness) of the Genset power feed wire was so loose it had pulled totally out of the terminal block connector. While working on Leg 2, the Leg 1 black genset harness wire came totally loose. I re-did the connections properly and fired up the generator.  The Alladin coach electrical status now showed that the generator was showing 118 volts plus on both legs. I waited a few minutes and then turned on the three roof-top ac units to "condition the brushes" as suggested. What a joy to have the units fire up properly.

While troubleshooting the transfer switch, due to the low quality terminal block connections from the generator, I began to suspect that an inexperienced RV repair center worker had done previous generator work. In that regard, the prior owner had spent a small fortune to have the generator control board replaced, which is likely when the poor electrical connection work occurred.

I am very grateful to all of the good people on this forum who took the time to respond to my post. I now have an up and running 12.5 kw diesel generator in which the repair did not cost me anything more than my time.

[Tom Cherry]

4 hours ago, Lee Smith said:

Problem Solved.
Thank you to all who provided so very much detailed and on target information that allowed me to troubleshoot the "Transfer Switch" and "Surge Suppressor" which enabled me to eliminate both as the problem. 

The solution was on page 12-6 of the Onan HDCAB Service Manual as follows:
NO AC POWER WHEN GENSET IS RUNNING
3. Check voltage at genset AC output terminal block TB2 when the genset is running. If there is approximately
120 VAC across TB2-1 and TB2-3 and across TB2-2 and TB2-3, repair or reconnect the wiring
between the genset and the main vehicle distribution panel. If there is no voltage, go to Step 4.
4. Check for proper AC harness connections and repair as necessary (p. A-3).

I removed a small generator topside panel to gain access to the AC output terminal block TB2 and check the voltage readings. The voltage readings were exactly what I had measured at the transfer switch terminal block.  Leg 2 (white genset to red harness) of the Genset power feed wire was so loose it had pulled totally out of the terminal block connector. While working on Leg 2, the Leg 1 black genset harness wire came totally loose. I re-did the connections properly and fired up the generator.  The Alladin coach electrical status now showed that the generator was showing 118 volts plus on both legs. I waited a few minutes and then turned on the three roof-top ac units to "condition the brushes" as suggested. What a joy to have the units fire up properly.

While troubleshooting the transfer switch, due to the low quality terminal block connections from the generator, I began to suspect that an inexperienced RV repair center worker had done previous generator work. In that regard, the prior owner had spent a small fortune to have the generator control board replaced, which is likely when the poor electrical connection work occurred.

I am very grateful to all of the good people on this forum who took the time to respond to my post. I now have an up and running 12.5 kw diesel generator in which the repair did not cost me anything more than my time.

That is great news.  And we all learned a little more trivia about these behemoth monsters we love, most of the time…. Rolling down even a good highway vibrates things beyond comprehension.  My only advice, since you now seem more electrically “experienced”……take the time to PM the main circuit breaker panel and tighten every terminal or screw you see when you pull the cover….obviously with an unplugged shore line and turning OFF the main breaker on your now running perfectly 12.5 KW energy source.

Thanks for the feedback.

[cbr046]

On 5/24/2022 at 12:06 PM, Larry Laursen said:

I had my ESCO ATS fail on my unit last year.  The wire coming from the control circuit board fell off and wouldn't close the relay on the generator side. 

Did your ATS relay click closed, immediately reopen and repeat ~ every 5 minutes?  I'm having a similar problem.

- bob

 

[Larry Laursen]

On mine nothing happened when it switched to generator. The wire was off and no action occurred. It sounds like the delay circuit is bad on yours. Try calling ESCO they are helpful.