Rear A/C Loses Power on Generator in 1999 Adventurer 35C

[levasseurjohn]

The back AC shuts off within 15 seconds of the generator being turned on. Front AC unit continues to run. When I turn the generator off, the back AC unit starts. I turn off the front AC, and the back still shuts off after 15 seconds of the generator being on. The automatic transfer switch is working as the front AC unit works on both shore AC and the generator. Any idea what is causing this?

 

[Eagle5]

Hi John,
What year and model do you have? Some of the double air-conditioner units were made with only 30amp service. Is that the case for you?
Eagle5

 

[levasseurjohn]

1999 Adventurer 35C. Has 2 units. Works fine on shore power, both units. With the generator and only turning on the back unit, it gets no AC Power at the unit. Front Unit works fine, with either power. It seems that somewhere the AC to the Air Conditioning units separates.

Does Transfer Switch seperate the AC from the generator inside the box? Is there two seperate wires and seperate relays inside the box?

 

[Morich]

I took a look at the 110AC electrical drawings for the 99Adventure and found there are actually six different wiring schemes for the 35C!
So we need to get down to exactly how your RV was builtby checking a few things like how many breakers are at your load center. Since RV have a habit of getting things added or changed over the years, the more dire way may be to let you look at teh drawing and tell us which layout you may have?
We have to be aware things may have gotten changed but if you can spot which load center look like what you see, that might be a good start as some do look like they might do what you find on the rear air unit.
Can you go to this drawing and compare to what you see at teh load center?

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/1999/130506.pdf

I'm pretty sure you can skip over the first two at top as they do not have the automaic transfer switch and you do not mention changing the plug at the cord.

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/1999/130506.pdf

We neeed to sort if you have 8,9, or 11 breakers and whetheeeeeer you have a 30 or 50 amp coach? Sorry lots of options on that one!

 

[Eagle5]

It looks like three different generator options were available for your motorhome:

https://www.winnebago.com/Files/Images/Winnebago/brochures/1999/99-Adventurer-bro.pdf

1. What is the model of your Generator?
2. Does your shore power cord have three prongs (30 amp) or four prongs (twin 50 amp)?
3. Does your Generator surge? (RPMs up and down)
4. Measured from a 120 VAC outlet, when running on the Generator, what is the exact voltage when:
   • Not running either Air Conditioner?
   • Running just the front Air Conditioner?
   • Running just the rear Air Conditioner?

 

[levasseurjohn]

I took a look at the 110AC electrical drawings for the 99Adventure and found there are actually six different wiring schemes for the 35C!
So we need to get down to exactly how your RV was builtby checking a few things like how many breakers are at your load center. Since RV have a habit of getting things added or changed over the years, the more dire way may be to let you look at teh drawing and tell us which layout you may have?
We have to be aware things may have gotten changed but if you can spot which load center look like what you see, that might be a good start as some do look like they might do what you find on the rear air unit.
Can you go to this drawing and compare to what you see at teh load center?

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/1999/130506.pdf

I'm pretty sure you can skip over the first two at top as they do not have the automaic transfer switch and you do not mention changing the plug at the cord.

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/1999/130506.pdf

We neeed to sort if you have 8,9, or 11 breakers and whetheeeeeer you have a 30 or 50 amp coach? Sorry lots of options on that one!

UPDATE... Generator running, the Power Control panel switches to the generator as it should, and the LED is on. The Rear AC Fan and Compressor LEDs are on, and the rear AC is not working. I turn on the front AC unit and it's drawing 14A. I turn on the microwave, and it trips the 32A breaker. Within 5 seconds the Rear AC Compressor and Rear AC Fan go out. When the LEDs were on for the rear it wasn't working. With shore power it works as it should.

When shorline power is on, LEDs for rear are on and it works. With generator LEDs are on but it doesn't work.

I will now go check the circuit breaker panel. OH, I almost forgot, THANK YOU for the help in understanding this issue.

 

[Morich]

HAH! If you can excuse funky typing and forgetting what I had already written, I can certainly accept any minor things like getting thanks BEFORE we know it works!
Maybe we can just buy each other coffee the next time we meet?
My two years of high school typing class went out the window typing code for four years of military! My mind never quite got reconnected to my fingers in the right way!

 

[levasseurjohn]

UPDATE... Generator running, the Power Control panel switches to the generator as it should, and the LED is on. The Rear AC Fan and Compressor LEDs are on, and the rear AC is not working. I turn on the front AC unit and it's drawing 14A. I turn on the microwave, and it trips the 32A breaker. Within 5 seconds the Rear AC Compressor and Rear AC Fan go out. When the LEDs were on for the rear it wasn't working. With shore power it works as it should.

When shorline power is on, LEDs for rear are on and it works. With generator LEDs are on but it doesn't work.

I will now go check the circuit breaker panel. OH, I almost forgot, THANK YOU for the help in understanding this issue.

PANEL HAS 8 breakers.

Another approach. Plugged in AC to 30A service. Both ACs work. Put on microwave and within seconds, back AC shuts off and Power Management panel LEDs are out. Turn of microwave and within 30 seconds LEDs come back on and I turn off then on back AC and it works.

Second test: With shore power, turn on generator. Within seconds rear AC goes off while LEDs stay on. Turn off generator and rear AC comes on again.

 

[levasseurjohn]

HAH! If you can excuse funky typing and forgetting what I had already written, I can certainly accept any minor things like getting thanks BEFORE we know it works!
Maybe we can just buy each other coffee the next time we meet?
My two years of high school typing class went out the window typing code for four years of military! My mind never quite got reconnected to my fingers in the right way!

Same here. Flunked typing in high school but later wished I had paid attention when I became a computer programmer. Since then I have written 10 books and it came in handy. I later wished I had paid attention in English class as well.

This seems like a confusing issue with a simple answer. Having the schematics is the key.

 

[Eagle5]

30 amp service cannot run two air conditioners very well. Typically, twin 50 amp service is required.

 

[levasseurjohn]

It looks like three different generator options were available for your motorhome:

https://www.winnebago.com/Files/Images/Winnebago/brochures/1999/99-Adventurer-bro.pdf

1. What is the model of your Generator?
2. Does your shore power cord have three prongs (30 amp) or four prongs (twin 50 amp)?
3. Does your Generator surge? (RPMs up and down)
4. Measured from a 120 VAC outlet, when running on the Generator, what is the exact voltage when:
   • Not running either Air Conditioner?
   • Running just the front Air Conditioner?
   • Running just the rear Air Conditioner?

Orion 5500... cord is 30A. Shore power all is well. Both work fine. Turn on generator, rear AC goes out, but power management show LED for read on. Shut off front AC makes no difference. With shore power, overload works as it should when it reaches 32A with both ACs and microwave. Rear shuts off and LEDs on management panel go out as they should. When I turn off microwave, LEDs come back on after 30 seconds. If I recycle the rear AC it comes on again.

 

[Eagle5]

Do you mean an Onan 5000? If you have an Onan 5500, it looks like the generator was replaced at some point, as the 5500 didn't come into production until the early 2000s. What is confusing to me is that you have a 30 amp shore power cord to go with a 50 amp style generator.

 

[levasseurjohn]

Orion 5500... cord is 30A. Shore power all is well. Both work fine. Turn on generator, rear AC goes out, but power management show LED for read on. Shut off front AC makes no difference. With shore power, overload works as it should when it reaches 32A with both ACs and microwave. Rear shuts off and LEDs on management panel go out as they should. When I turn off microwave, LEDs come back on after 30 seconds. If I recycle the rear AC it comes on again.

I am doing a hard reset of everything, especially to Power Management System. I disconnected the power cable to all of the batteries for at least half an hour. I will be back.

 

[Waterbug]

Do you mean an Onan 5000? If you have an Onan 5500, it looks like the generator was replaced at some point, as the 5500 didn't come into production until the early 2000s. What is confusing to me is that you have a 30 amp shore power cord to go with a 50 amp style generator.

If he indeed has a 50 amp generator connected to a 30 amp RV, the factory schematics may be useless. No telling how it is wired until you kill all power and ohm things out.

 

[creativepart]

While you do find the Onan 5500 on 50-amp RVs it only puts out ~46 amps. It operates as a single-phase generator but distributes power through two separate output lines (or legs), typically protected by a combination of dual 30-amp or 30/20-amp circuit breaker.

So, assuming that someone at some point replaced the 4000w genset your RV should have come from the factory with, it likely still has the standard 30-amp load limiting EMS that sheds loads when on 30-amp power.

Of course, running two A/Cs on 30-amp is not always a sure thing. But running the A/C and the microwave at the same time on generator/shore power usually will mean that the rear A/C will turn off and the lounge A/C MAY drop the Compressor but leave the fan running.

Your RV is 27-yrs old. Who knows what one or more previous owners have done to "improve" your RV. In fact, many... most?... 30-amp gas motorhomes will not come standard with two A/Cs. So, it's possible that a previous owner replaced a fan in the bedroom with an A/C unit. And, who knows what's been done to accomplish this addition. IF that's what has happened??

 

[levasseurjohn]

I am doing a hard reset of everything, especially to Power Management System. I disconnected the power cable to all of the batteries for at least half an hour. I will be back.

Disconnected +, Red, terminals on all batteries, including the Cab. Let's sit for 45 minutes, reconnect, and the same. Power Management shows the Rear AC LED is on, but no rear AC.

 

[levasseurjohn]

1999 Adventurer 35C. Has 2 units. Works fine on shore power, both units. With the generator and only turning on the back unit, it gets no AC Power at the unit. Front Unit works fine, with either power. It seems that somewhere the AC to the Air Conditioning units separates.

Does Transfer Switch seperate the AC from the generator inside the box? Is there two seperate wires and seperate relays inside the box?

It does separate because on the Power Management Panel it shows Rear AC Unit and Rear Fan.

 

[levasseurjohn]

I just found through research that there is a Power Management display panel with only a 4 wire connector and a Power Management Module. I read where the module is behind the AC circuit breaker panel. Where the display seems to be displaying correctly with GENERATOR led on and the other four leds on the right are all on saying the rear AC should be working. A few members have been helping but no answer yet. I have the Powerline manual that came in the information folder.

Anyone ever run across this?

 

[levasseurjohn]

I just found through research that there is a Power Management display panel with only a 4 wire connector and a Power Management Module. I read where the module is behind the AC circuit breaker panel. Where the display seems to be displaying correctly with GENERATOR led on and the other four leds on the right are all on saying the rear AC should be working. A few members have been helping but no answer yet. I have the Powerline manual that came in the information folder.

Anyone ever run across this?

The module is beside the AC breaker panel cover. I need to take it out to access the output connector and measure the voltage. I found one screw, but it is still secure, and I don't see another screw.

 

[levasseurjohn]

The module is beside the AC breaker panel cover. I need to take it out to access the output connector and measure the voltage. I found one screw, but it is still secure, and I don't see another screw.

UPDATE... I was just in the bedroom with the cover off the AC wires with the generator on. NO AC power. When I turn the unit off and on I can hear the relays clicking in the control. Both fan and compressor relays click. That leaves the AC power when the generator is on. One hiccup to that is the front AC is working all the time with the generator. Back unit no power.

Any ideas? The Transfer Switch has AC coming in andAir either shore power or generator going out. Somewhere, the Generator AC power splits again. One for each AC Unit. I guess there is a schematic somewhere that shows where they split.