Basement a/c issues

This query is made to anyone that has a good working knowledge of Winnebago basement air conditioner systems and Marquis Gold gensets.

My 2005 Adventurer has 30 amp service and basement a/c. When I use shore power, the a/c runs properly, with both compressors kicking in and providing good, cold, strong air flow. However, when I use my genset, a Marquis Gold 5500 which should be large enough to put out 50 amps if required, the a/c #2 compressor will not kick in. On shore power, I will see an initial amp usage upon startup of between 35 and 49, with a run usage of 23-24 amps. On genset, the startup usage shows something in the 20-25 amp range and then settles to 13-14 amps. Obviously, the #2 compressor isn't coming on. The start and run capacitors have been checked and are good.

There are two a/c breakers on the genset - a 30 amp and a 20 amp. I have read that if the coach has two roof a/c units, the 30 amp breaker runs the front a/c and the entire coach, while the 20 amp breaker runs the rear air. I cannot find anywhere what that 20 amp breaker is used for if basement air is installed instead of two roof units. However, on numerous occasions, I have noticed the 20 amp breaker thrown and don't know why.

Is there a possibility that the #2 compressor is wired to that 20 amp breaker? If so, what would make that breaker continue to throw and not allow the #2 to come on? Could the breaker be bad, and if so, how can it be replaced? I am only guessing at these suppositions but logic leads me to this point due to lack of knowledge. This is why I need someone very familiar with this setup to give me help.

I have plans to convert the coach to 50 amp service next year but want to ensure I will also have 50 amps coming from my genset. Obviously, if it can't even run the #2 compressor, it isn't going to give me a full 50 amp service if wired for it.

Thanks in advance to anyone who can help with this issue.

By the generator label of 5500 and if indicating 5500 watts , that would be 48 amps approximately and that number may be peak and not continuous run amps. But the two breakers on the gen set tell the story.

Usually (at least on mine) the basement air conditioner starts the first compressor and fans, runs for a bit, then the second compressor starts. This delay eases the total amps required while starting the second compressor. Your generator should be able to handle that ok. Is it possible for the 20 amp amp breaker to be wired to the 2nd compressor?? I would say it has to be unless you have found a way to create amps available without that. The breaker itself may be weak and now blows at considerable less amps than its rated value though. You could change it out and see what happens.

Changing the coach service to 50 amps won't change the total output available while under genny power but it would be nice not to have to worry about amp draw for everything else when plugged in. (My RV is 50 amp but with no generator! I have to solve the lack of startup of the second compressor this fall, but my problem is not likely the same as yours. I suspect a relay problem along with a new start capacitor for now.!!)


Just food for thought!!!

The #2 compressor in the basement air does run on the 20 amp output of the generator. You can download the wiring diagrams from

http://winnebagoind.com/product-resources/product-information

There is a big difference between the 50 amps from the generator and the 50 amp service from shore power. The generator has a 30 amp and a 20 amp output, the 50 amp shore power has two 50 amp, 120 VAC  outputs.

John Hilley said:

The #2 compressor in the basement air does run on the 20 amp output of the generator. You can download the wiring diagrams from

http://winnebagoind.com/product-resources/product-information

There is a big difference between the 50 amps from the generator and the 50 amp service from shore power. The generator has a 30 amp and a 20 amp output, the 50 amp shore power has two 50 amp, 120 VAC  outputs.

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John, Thanks for the input. I downloaded the wiring diagram but it was completely foreign to me. It's good to know the #2 compressor is wired to that 20 amp breaker and I think that may be my entire problem. But now I need to find out how to replace the breaker if it is bad or weak.

I'm already aware that converting to 50 amps will give me a total of 100 while on shore power and only 50 on genset. I just want to make sure I have all 50 amps from the genset.

The tripping CB is probably caused by problems with the load (compressor), loose wires, or bad CB.  The Powerline controller can shut off the 2nd circuit (20 amp) to the basement a.c. system.  Beau

I know mine is a 2003 sightseer but i have the 5500 generator on mine too. I installed a transfer switch on mine 30 amp and after looking at the drawing i am going to add a 50 amp on mine.Like everyone said the 20 amp is only used for  the #2 A/C.Since you have a 30 amp system do you have a selector switch by the breakers that says shore or Gen. Mine does and put it on shore and the #2 will run on shore power but if I start the Gen it will feed both on the 30 amp system but the amps is up there. When I put it in gen mode I can run the both and I still have power to run other things on #1 system. This is a simple up grade

beau2x said:

The tripping CB is probably caused by problems with the load (compressor), loose wires, or bad CB.  The Powerline controller can shut off the 2nd circuit (20 amp) to the basement a.c. system.  Beau

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Beau - your post kind of tells me what I've been trying to find out. If my problem is limited to what you listed, then I am going to assume the problem is in the breaker. Both compressors have been tested and show #1 drawing 7.9 amps and #2 drawing 8.2 amps. The draw is supposed to be 8.9 amps per compressor, so this isn't bad for an eleven year old unit. The wiring and capacitors have been checked and cleaned. So it appears the only other issue could be the CB, which is what I suspected. And yes, when the draw is too high, the EMS lights will blink off for the #2 compressor as well as the water heater, fan speed and refrigerator. Now, the question is how to replace the breaker. The on/off switch is located on the side of the generator and I'm not sure how to tear into it.

JohnDale said:

I know mine is a 2003 sightseer but i have the 5500 generator on mine too. I installed a transfer switch on mine 30 amp and after looking at the drawing i am going to add a 50 amp on mine.Like everyone said the 20 amp is only used for  the #2 A/C.Since you have a 30 amp system do you have a selector switch by the breakers that says shore or Gen. Mine does and put it on shore and the #2 will run on shore power but if I start the Gen it will feed both on the 30 amp system but the amps is up there. When I put it in gen mode I can run the both and I still have power to run other things on #1 system. This is a simple up grade

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John - I have looked all over for a switch such as you described and cannot find one. Are you talking at or near the breaker panel? For on the panel, I have nothing but breaker switches that can be thrown on or off. If you can send me a picture of what you have, I might be able to track it down on my coach.

John Stephens said:

John - I have looked all over for a switch such as you described and cannot find one. Are you talking at or near the breaker panel? For on the panel, I have nothing but breaker switches that can be thrown on or off. If you can send me a picture of what you have, I might be able to track it down on my coach.

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You don't have such a switch. You should have an EMS (energy management system) and not have to worry about switching things off.

John Hilley said:

You don't have such a switch. You should have an EMS (energy management system) and not have to worry about switching things off.

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John - You are correct. I have a Powerline EMS made by Intellitec that does it for me.

Are you certain you are a 38J?  I was going to look at your wiring diagrams and they don't list a 38J, there's a 38G but that's the only model listed at 38'.

Before you tear into the generator to change the 20 amp breaker I would use a clamp on ammeter and see what sort of current is on that 20 amp genny leg.  I have had breakers go bad before, but that's a fairly rare situation.

John Canfield said:

Are you certain you are a 38J?  I was going to look at your wiring diagrams and they don't list a 38J, there's a 38G but that's the only model listed at 38'.

Before you tear into the generator to change the 20 amp breaker I would use a clamp on ammeter and see what sort of current is on that 20 amp genny leg.  I have had breakers go bad before, but that's a fairly rare situation.

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John - I have already downloaded the electrical from Winnebago so I know it's on their site. Yes, it is a 2005 Adventurer 38J. I just wish I could read the schematic but I'm not an electrician.

John, I am an electrician and those diagrams are tough to understand.  Beau

beau2x said:

John, I am an electrician and those diagrams are tough to understand.  Beau

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Well, that makes me feel a little better. LOL

I'm also an electrician and more familiar than most electricians with motor homes and I find them difficult. From what I've seen on RV forums, that breaker does fail.

While not an electrician, I am schooled in electronics and have an Extra class Amateur Radio license and I concur with all of the 'hard to read'  evaluations.  What I do when I need to understand one of Winnie's obtuse diagrams is to print the diagram out and then use a highlighter marker on the particular circuit.

Thanks to everyone who responded to this query. With the information I was able to compile from the various posts, I was able to call Winnebago Customer Service today and act somewhat informed.

Winnebago confirms that with basement a/c, the 20 amp breaker on the genset powers the #2 compressor. The CSR stated that since I have had the a/c unit and both compressors checked out and given a clean bill of health, there should be only one thing that could be causing the problem I have of the 20 amp CB tripping every time the #2 compressor tries to start - the CB is weak or bad. I inquired into the possibility of having a loose or bad wire that could cause a short and trip the CB and was told that if the #2 compressor is working on 30 Amp shore power, then it cannot be the wiring. He felt comfortable telling me to order a breaker from Onan. He also suggested that because this is not a standard breaker, to have a mechanic or electrician install it that knows what they are doing. I dropped by my mechanic who is waiting for solenoids on back order from HWH to repair my slide and told him to add this to the list.

This is probably what you want:
http://www.americanrvcompany.com/Cummins-Onan-320-1683-20-Amp-Circuit-Breaker-Kit-for-Marquis-Gold-and-Platinum-Camper-Trailer-RV-

Replacing it is easy enough, except for getting the covers off for access. Sometimes that can be a real bear in an RV genset compartment.

So is compressor #2 the only load on that 20A genny breaker?

John Canfield said:

So is compressor #2 the only load on that 20A genny breaker?

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It should be the only load on that breaker.