120v and generator…

[modrob]

Different systems in many rigs. Some autostart the genny when shore power is lost, other may have you switch it manually. Some have no switch and require you to plug the shore power cord into an outlet the genny is hooked to. Since you have an auto transfer switch, it would seem it should auto switch......lol. But maybe not. IF you have a manual it should explain the system you have.

Yep. I need to see if I can find some kind of manual for the auto switch—I did find a copy of the wiring instructions.
The Allegro manual doesn’t shed any more light on it either.

 

[modrob]

Today I had a chance to recheck breakers. Restarted the generator, and still no power. I also found one GFI outlet next to the hallway sink. I was able to check it after I shut down the genset and then plugged in to shore power. All outlets worked and the GFI outlet tested fine…I’ll try again tomorrow and see if the wife can help so that I can be near the switch to listen for that “click”…

 

[TheLooks]

It is possible for the generator to not be working. It is an Onan? They are more complex then most as they have a lot of sensors and systems in place that can fail. Very possible to run fine and not put out any power. Put up your model number, not the one that says how many Kw it is. I have lots of manuals but troubleshooting can be a nightmare. The Cummins dealer here in Chattanooga requires them to be removed from the chassis to work on them. As mobile techs there is not a lot we can do with them.

 

[modrob]

It is possible for the generator to not be working. It is an Onan? They are more complex then most as they have a lot of sensors and systems in place that can fail. Very possible to run fine and not put out any power. Put up your model number, not the one that says how many Kw it is. I have lots of manuals but troubleshooting can be a nightmare. The Cummins dealer here in Chattanooga requires them to be removed from the chassis to work on them. As mobile techs there is not a lot we can do with them.

Could very well be. It’s an Onan Marquis 7000.

 

[Kevin D Pem]

Could very well be. It’s an Onan Marquis 7000.

I would check gen output at the gen. The issue with many Onan generators is the field compensation circuit. This circuit changes the field voltage to manage voltage sag. Although its been some time, as I recall it has brushes. You might check them for possible replacement next.

 

[modrob]

I would check gen output at the gen. The issue with many Onan generators is the field compensation circuit. This circuit changes the field voltage to manage voltage sag. Although its been some time, as I recall it has brushes. You might check them for possible replacement next.

Whew! By the time I get this coach in shape, I’ll be a full-fledged tech! LOL Problem is I have other major projects going on and I have to squeeze the RV in when I can…I guess I have to finally admit to myself I got taken pretty good on this coach. I’m about sick with all I’ve found and more to come I’m sure…totally my fault by not doing a thorough inspection and trusting the old couple sellers.
Thanks for your help and guidance.

 

[Kevin D Pem]

Whew! By the time I get this coach in shape, I’ll be a full-fledged tech! LOL Problem is I have other major projects going on and I have to squeeze the RV in when I can…I guess I have to finally admit to myself I got taken pretty good on this coach. I’m about sick with all I’ve found and more to come I’m sure…totally my fault by not doing a thorough inspection and trusting the old couple sellers.
Thanks for your help and guidance.

My mom used to say as people age they become worse images of what they were when young!!! Just because you see white hair doesn't mean they can be trusted!!! Till the day she passed, she had a mellow soul, she must have been a joy to raise!!!

Oh if no brushes the excitation coil in the field would be my diagnosis.

 

[modrob]

UPDATE:
Finally got around to looking deeper. There are only two breakers on this unit, on left side, to the right of the Start/Stop rocker switch. Evidently I couldn’t read the labels clearly and had them OFF instead of ON. Corrected that, and voila! 120 volts now showing up inside. Curiously, I turned on the FAN switches on the overhead AC units, but nothing. Hmmmm…

 

[TheLooks]

Put up a pic of the AC unit and thermostat. By pic I mean the inside cover on the ceiling and any lettering on it.

 

[modrob]

Put up a pic of the AC unit and thermostat. By pic I mean the inside cover on the ceiling and any lettering on it.

I’ll have to get a pic of the thermostats soon…but here are the labels inside both roof units.

 

[TheLooks]

My guess is if you turn on the AC or heat unit and nothing happens it is either in the control box in the AC unit or the thermostat.

 

[modrob]

My guess is if you turn on the AC or heat unit and nothing happens it is either in the control box in the AC unit or the thermostat.

A few weeks back (warm weather) I had both units working fine (cooling) but was on shore power…

 

[TheLooks]

Shore power or 120 vac is necessary for the AC unit to run, but it still is controlled by 12 vdc. The furnace only runs on 12 vdc so unless the battery is dead and the convertor is dead, it will run without 120 vac. The fans on the AC units need 120 vac to run but are TOLD to run by a relay controlled by 12 vdc.(thermostat and control box in ceiling AC unit) Check your voltage with a meter and check the fuses.

 

[modrob]

Shore power or 120 vac is necessary for the AC unit to run, but it still is controlled by 12 vdc. The furnace only runs on 12 vdc so unless the battery is dead and the convertor is dead, it will run without 120 vac. The fans on the AC units need 120 vac to run but are TOLD to run by a relay controlled by 12 vdc.(thermostat and control box in ceiling AC unit) Check your voltage with a meter and check the fuses.

Yes sir, I understand. The furnace part I haven’t started to look into yet—propane is empty anyway…but I’m sure like everything else I’ve been finding, it’ll have issues as well…
All batteries are new and charged…(2 coach and 1 chassis)
I’m just confused for the time being on why AC units/fans would work on shore power, but not with genset running…all breakers/fuses appear to be good so far too.
I’ll keep reading your reply a few more times—I may be missing something…

 

[TheLooks]

Nope, you got it. I would check the transfer switch now. It is supposed to automatically go to generator when the shore power is removed.....or if you have an old system, you have to plug the generator in manually in the electric bay.