Can't Run Both AC's on Gen-Set

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OkieDave

OkieDave

Member
Joined
Aug 29, 2010
Posts
10
Location
Oklahoma City OK
I have a:
2001 Winnebago Adventurer 32V
Basement Air
Onan 5500 Generator.
30A Shorepower

Ok, now the problem. When I'm on shore power (30A) I can run both compressors on the basement air when the temperature difference calls for it.

When I run the gen-set, only 1 air will come on no matter what the temperature difference is.

On the Intellitec, it shows that I'm on 'Gen-Set' so it is sensing that I'm getting something from the generator and that the amperage with the one unit running is 14 amps. All of the lights are on for the systems that it would shed if necessary. 2nd Compressor light is on so it's not shedding it. The circuit breakers on the generator are both on.

Why am I not getting enough power to run them both?  Is anyone else able to run both compressors on their basement air when on gen-set.  Usually one is enough but spending time in the Arizona desert at 110 degrees, I needed both running.  I something wrong, or is it wired that way on purpose?

Thanks

 
Since one a/c is running, it can't be the automatic tranfser switch on a 30A rig. Only 30A is switched, and that appears to be working.

But how does the second generator circuit feed anything on this coach? Is it direct wired to the 2nd compressor, like it would be on a roof air? Is there a shore/generator switch, or a front/rear a/c switch with basement air? Can some Winnie owner with a 30A coach elucidate?
 
Okay - I looked at your wiring diagram (the 30 amp version.)  I strongly suspect the transfer switch is the culprit (you do have one.)  It appears the second compressor is wired directly to the transfer switch  :eek:, both hot legs of the genny are of course wired to the transfer switch.  My supposition is the second compressor is supposed to pick up one of the two gen set outputs from the transfer switch when switched to gen set mode, and in your case, that's not happening.

If you are comfortable working around live voltage, I would take the cover off the transfer switch and start metering around with the genny running.  If you aren't comfortable with the above, try giving the box a sharp rap with a block of wood or similar and see if that helps.
 
I have a 2000 suncruiser 35U with 3o amp power and a 5.5k Onan generator. I can run both compressers on shore and gen power. The second comp is wired thru the transfer switch i beleive, to the 20 amp leg of the gen and as such it will NOT show current draw on the intellitec display for the 2nd comp on gen power. The only way i can tell if the 2nd compresser is running is wait for approximately 20 seconds after the first compressor starts and listen for the compresser to start, you can tell by the load the comp puts on the gen plus it's fairly easy to hear it if you stand towards the basement unit (hallway/bathroom for me in the 35U). Either a start capacitor is bad or you don't have power on the 20 amp leg of the genny which you can check by looking at the leds on the basement air control board.

kl
 
I will check a few things tomorrow morning.  Where do you get to the board on the basement AC?  I know there is nothing wrong with the AC (Like capacitor) since it works fine on shore power.  Also, on Genset it does not get nearly as cold as on shore power so I really think the second compressor is not coming on.
Thank you everyone who has responded and I will get you more info tomorrow.
Dave
 
I checked the transfer switch and the second AC output is hot.  Everything is hot except the shore power input.  When I put it on shore power, everything is hot except the line from the gen.  So, it looks like everything is OK at the Transfer switch.  For some reason I think the EMS is not allowing the thermostat line for the 2nd AC to close when it is sensing the gen-set.  It has an Intellitec PowerLine Model 620.
 
There are diagnostic LEDs on the basement air control board that might help to determine what's going on with the AC.  You will need to raise up the hinged basement panel/door and expose the AC.  There will be a removable panel which will expose the board (at least this my experience with my AC.)  It would be worth a visit to RVP's website to download the service manual for your AC.

I don't think the EMS is controlling any thermostat wiring.  Mine has a relay for the 110 volt line of each load it sheds. 

You have an interesting problem  ???
 
Did you ever find the cause of the second ac not coming on when you were using the generator. I have the exact same problem as you described it.
 
A 30-amp unit can still use a 50 amp transfer switch. Each compressor will run off one leg of the generator. If one side of the transfer switch is faulty one of the compressors won't get power. If plugged into shore power, the 30 amp cable will bridge both sides of the transfer switch and both compressors will get power.

If you determine it is the transfer switch, be aware that the Parallax switch you have is not designed to operate while driving. I would recommend replacing it with another brand. Progressive Dynamics makes one that the manufacturer says is designed to operate while driving.
 
Hi Ho:  KentL has described the situation correctly.  The question is how you know the second compressor isn't running?  It does not show up on the one-place as a current draw because it is fed directly from a 20 amp breaker on the generator and doesn't go through the current sense torroid. 

What you need to do is to verify first that the 20 amp breaker on the generator is set.  Then you can verify that power gets to the  second compressor.  If it runs when connected to shore power it has to be something in this line.

I got caught with this situation just after we got our Suncruiser.  Check the 20 amp breaker first and make sure power there is 120 volts at the output.
 
Dirk,
are you saying that you will not see the amp draw of the second ac when on the generator only will see it when you are on direct power. If that is so how do you know you have both ac's on when on gen set. Is there any way to tell both are running?

Thanks
 
Tejas, the EMS does not look at the generator leg that powers the second ac compressor. The only way to tell, for me at least, is to just listen for the compressor to kick in.  In most of the 30 amp winnies with basement air the single leg of shore power feeds thru the leg 1 of the transfer switch to the main 30 amp breaker then thru the 20 amp air conditioner breaker to the leg 2 of the transfer switch to the #2 AC compressor so sll shore power is monitored by the EMS where as the generator leg 2 goes thru the transfer switch straight to the #2 AC compressor. You can verify this with the 110 volt AC wiring diagram that Winnebago has on thier website.

kl
 
Would be surprised if  the 2nd generator output (20A) goes through a transfer switch at all... It likely goes direct to the Air Conditioner through a circuit breaker either on the generator or in a fuse panel.. There is no reason to put it through a transfer relay as the AC is usually the only thing being powered from that winding.
 
Alfa38User said:
Not sure the 2nd generator output (20A) goes through the transfer switch at all... It likely goes direct to the Air Conditioner through a circuit breaker either on the generator or in a fuse panel.. There is no reason to put it through a transfer relay as the AC is the only thing being powered from that winding.
Click to expand...

I converted an Itasca from 30 amps to 50 amps. If I remember correctly, both compressors are connected to both the generator and shore power. All of the poles in the transfer switch are used. It was a strange wiring job, but I don't remember the details.
 
Alfa38User said:
Would be surprised if  the 2nd generator output (20A) goes through a transfer switch at all... It likely goes direct to the Air Conditioner through a circuit breaker either on the generator or in a fuse panel.. There is no reason to put it through a transfer relay as the AC is usually the only thing being powered from that winding.
Click to expand...

The 20 amp side of the gen does indeed go thru the transfer switch, you can look at the wiring schematic and see it. If this wasn't done then shore and genny power would not be isolated.
 
The 20 amp side of the gen does indeed go thru the transfer switch, you can look at the wiring schematic and see it. If this wasn't done then shore and genny power would not be isolated.
Click to expand...

Not really - it is commonly done just that way in other brands and models.  The rest of the wiring for the 20A circuit for the rear a/c can be done totally separate, with no wire connection at all in common with shore power. It's just a different design choice.
 
This may be something you have already checked but I didn't see any mention of it.
Have you checked both of the breakers on the generator? One of them is for the line going to the second AC.
 
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