‘22 Forza ATS issue

[BirchyBoy]

I drove the new RV back from Miami to Denver and all was good. I could switch the generator on and run the A/C’s etc. I parked it Sunday and went out today to deliver bins of stuff from the old RV and wanted to run the A/C.

I turned the inverter master on, the chassis batteries and the coach batteries and fired up the generator. The Firefly screen showed the generator as running and delivering power but the AC wouldn’t come on. When I tried, the Firefly showed “shed” and also not all of the receptacles would work. If I turned the generator off, the inverter kicked in and powered some stuff up.

I didn’t take the cover off the ATS but there were no obvious burn marks or anything. There was no load on the circuits when I unplugged from shore power on Sunday morning.

We’re going to the mountains this weekend and I’m hopeful that the shore power will work. I can do without the AC’s while driving but also don’t want to have an issue like this the first time my wife goes.

Any suggestions on what to do?

[Morich]

First step to sorting questions will almost always be to know what RV you have.
Can you sort out which model?


From the mention of "shed" it would sound like you have a load shedding system but I would not normally expect it to shed the outlets as they are pretty low current draws.
So that leaves far too many guesses to begin. Every RV is different and there may be some which do shed outlets under some conditions.

[creativepart]

Check the circuit breaker’s directly on the Onan generator. If they’ve tripped the generator will run but no power.

Also, why did you turn the inverter on if you were going to run the generator?

Oh sorry, you mean the A/C wouldn’t come on… not the AC. ignore that first paragraph above.

A/C is air conditioning.

AC is 110v alternating current.

[BirchyBoy]

Originally Posted by Morich

First step to sorting questions will almost always be to know what RV you have.
Can you sort out which model?
Attachment 186098

From the mention of "shed" it would sound like you have a load shedding system but I would not normally expect it to shed the outlets as they are pretty low current draws.
So that leaves far too many guesses to begin. Every RV is different and there may be some which do shed outlets under some conditions.

It’s a 36H. I don’t have the Winnebago serial number handy, just the chassis VIN. I’ll get the other one tomorrow.

I’ve noticed the Firefly says “shed” when it is trying to run both A/C’s on less than 50 amps.

[BirchyBoy]

Originally Posted by creativepart

Check the circuit breaker’s directly on the Onan generator. If they’ve tripped the generator will run but no power.

Also, why did you turn the inverter on if you were going to run the generator?

Oh sorry, you mean the A/C wouldn’t come on… not the AC. ignore that first paragraph above.

A/C is air conditioning.

AC is 110v alternating current.

I will be more careful with my use of AC and A/C in the future

I did check the breakers on the panel on the front driver side but did not see anything that had been tripped. I will have to look at the other breakers and see if anything looks amiss. The storage yard has some 50 amp outlets. I may plug it in tomorrow to see if shore power works.

[creativepart]

Originally Posted by BirchyBoy

I’ve noticed the Firefly says “shed” when it is trying to run both A/C’s on less than 50 amps.

That’s normal. On 30-amp your Load Center will allocate power to some things and shed loads that would otherwise trip the shore power pedestal breakers.

You can only run one A/C at a time on 30-amp shore power. And even one A/C is difficult to run when using the microwave.

Owning a motorhome requires you to learn a lot of things, such as all the things that use a lot of amps when starting/running.

[BirchyBoy]

I get that. But, if the generator was providing power to the coach, as it should be, no “ shedding” is needed. I think the inverter was trying to provide power and it couldn’t. I need to figure that part out.

[Morich]

OK, doing some checking it looks like both new and late builds are the same on this portion so we can begin to look what should happen!
No problem with me on the AC versus A/C as you are very likely to catch me getting that wrong! We do the best we can and move on!

But the shore line versus generator can be simple enough to look at. I also see very little shedding gizmos, so that may be a factor of not having full 50 amp service?

I made this snip of the power for your RV up to the inverter sub panel.
Click the snip or go direct to get the bigger, full drawing?
https://www.winnebago.com/Files/File.../000245233.pdf Last sheet and this is from the later build but looks the same as early build.


Basic idea is that you get two inputs of 110 power, either from generator or cord. The transfer switch decides which to pass on to the main panel.
But if you are plugged into 30 amp service, you only get ONE of these feeds.
NOTE:
You might spot what looks to me like they transposed the red/black wire colors coming out of the transfer switch but don't let that throw you. We have to go with two coming out and ignore wire colors at this point?

At the main panel that one feed goes to other breakers that spread out to other points where we use it or the inverter panel where it is broken down into different feeds that work through/ with the inverter.

Rather than jump directly into the inverter, I might want to first verify what I get with only one feed as a more direct and simple test.
If only having a single 110 feed, find out which air works?
I might turn the inverter output breaker off at that time as a way to cut any possible confusion if it is a problem. One air will work, one will not until plugged into 50 amp!
But both air should work when running generator, so that is the place I would start to verify the 110AC portion is doing right!
The if you turn on the inverter and things go bad, you know which way to chase it?
I think the "shed" is simply due to not having one leg of AC to confuse the readout! Easy to fake out a mechanical brain>>>>
I'm thinking with generator running and putting out both legs for a full 50 amp, the shed notice goes away and no worries as you do not have much load shedding involved on your RV. Something odd noted on the water heater but no major other parts for shedding power.

[ZimBob]

I had similar behavior in my 2021 Adventurer 29B and wound up replacing the transfer switch. You can read about my experience in this thread: https://www.winnieowners.com/forums/...ed-365302.html.

Hoping for a good outcome for you!

[creativepart]

Originally Posted by BirchyBoy

I get that. But, if the generator was providing power to the coach, as it should be, no “ shedding” is needed. I think the inverter was trying to provide power and it couldn’t. I need to figure that part out.

What generator does the Forza have… how many watts of output? If your water heater is on electric, your fridge is running, your house batteries are low and demanding lots of charging and both A/Cs are trying to run it’s definitely possible for the PCS to shed one A/C when on generator power.

In case you aren’t aware, the electric element in the water heater is a huge AC load. When on generator it’s best to have the water heater set to LP unless you are not using the two A/C units.

When you don’t have full 50-amp service the PCS system will automatically reduce power to the house battery charger first, then it will selectively run each air conditioner compressor. It may keep running the fan on one and the fan and compressor on the other and cycle back and forth between the two units.

[BirchyBoy]

Originally Posted by creativepart

What generator does the Forza have… how many watts of output? If your water heater is on electric, your fridge is running, your house batteries are low and demanding lots of charging and both A/Cs are trying to run it’s definitely possible for the PCS to shed one A/C when on generator power.

In case you aren’t aware, the electric element in the water heater is a huge AC load. When on generator it’s best to have the water heater set to LP unless you are not using the two A/C units.

When you don’t have full 50-amp service the PCS system will automatically reduce power to the house battery charger first, then it will selectively run each air conditioner compressor. It may keep running the fan on one and the fan and compressor on the other and cycle back and forth between the two units.

It has a 6k Cummins diesel generator, a Truma water heater that uses propane but is off and the microwave is unplugged. The Firefly detects that the generator is running but the generator isn’t delivering power to the coach. This is confirmed because no AC circuits are working once the Firefly detects the generator and disables the inverter. If the generator is off and the inverter is on everything is working as best it can.

[creativepart]

Originally Posted by BirchyBoy

The Firefly detects that the generator is running but the generator isn’t delivering power to the coach.

OK, that helps.

I would suggest you go out to the generator and look at the circuit breaker that is on the generator - it should be near the remote start button on the generator.

If that has tripped or been turned off by some repair person then the generator will start - but not put out any power.

If that's not the issue, then I would agree it sounds like it might be an ATS issue.

[Morich]

I feel it might be important to note that the Adventurer has an EMS and the Forza in question doesn't show one??
Forza with no EMS


Adventurer WITH EMS


I fully agree that finding out if the generator it working right is important but testing the output of the generator by checking if both Air will run is one quick way to do that when the correct meters are not on hand!

If both air run , it say that the generator is putting out power on both legs. If not then moving to find out why is needed. The inverter is still not involved at this point in testing!

[creativepart]

Originally Posted by Morich

I feel it might be important to note that the Adventurer has an EMS and the Forza in question doesn't show one??

Actually, the Forza does come with the Precision Circuits PCS (Power Control System) built in. It is in the Operator's Manual on section 4-7 and 4-8.

I figured it must, because of the "load shed" terminology.

POWER CONTROL SYSTEM
(PCS)
The Power Control System (PCS) monitors
the electrical usage of the appliances and
equipment in the motorhome and allows you to
use certain high energy appliances, such as the
microwave or washer/dryer, without overloading
the shoreline circuit breaker to prevent nuisance
tripping.
“Home” Screen
“DC” Screen
“Home” Screen
• Tap Water Pump to turn off/on

The system and it's control is on the RV's touch screen. Here is a screen shot of the PCS controls:

[Morich]

Ok! I will buy that as good enough proof that the drawings do not show the parts that you are finding! Always good to keep that in mind as we more and more to added parts from other builders. That will be another part much like steps and appliances which are NOT shown!
I get the feeling we are moving more and away from DIY and going into needing dealer repairs.
Now the big question may become whether the dealer techs are kept up to speed on RV or do we get into the same I found with cars and they will not be able to fix them when we DO take them in??
Life as we know it has certainly changed in lots of things, so I guess we have to expect change in the RV world, too.

Since the EMS is shown and how it is connected on your RV, I wonder why no sign of it on the later RV? Just supposed to know that like we get in the computer world!

[BirchyBoy]

Originally Posted by creativepart

Check the circuit breaker’s directly on the Onan generator. If they’ve tripped the generator will run but no power.

Also, why did you turn the inverter on if you were going to run the generator?

Oh sorry, you mean the A/C wouldn’t come on… not the AC. ignore that first paragraph above.

A/C is air conditioning.

AC is 110v alternating current.

Good call early on. The breaker had tripped. Thanks for all the help and suggestions.