Genrac question

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Keith Haw

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Jul 20, 2006
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29
Hello.
I have a question about the generator in my GeorgieBoy.. When I bought the MH it had a Kohler 5500W generator.. When I went to pick it up the Kohler would not start so the dealer swapped in a used 5500W Genrac..  The Kohler was a 50a gen so it would power both a/c units.  My question is, the Genrac only has a 20a and a 30a breaker and has trouble powering both a/c's.  Is this thing a 30a or 50a gen?  I have no paperwork or cannot find a serial number...
Thanks
Keith
 
5500 watt is 50 amp, normally on a generator like that it's wired so one ac, and only that ac, is on the 20 amp breaker, the rest of the rig is on the 30 amp breaker, and it works frairly well

Alas, the switch you have may be .... Different than what the Genrac is designed for,  This may require you replace the 20 amp breaker with a 30 (My rig has two 30 amp breakers, but the generator max out is still 5500, same as yours)

This, should be done with caution though, as ... Well, I don't know what is behind those breakrs

Look up "Intellitec" ATS (Automatic Transfer Switches) and they will show you what I'm talking about

Page six of the manual for model:Transfer Relay Delay 00-00803-100

describes what I'm speaking of
 
Thank you for the replies... I am not where I can get to the MH right now, will be a week or 2..  But I could not find a model number anywhere, just a sticker that list it as a single phase, 120v gen.  They removed the front cover when thay installed it for cooling reasons, maybe it was there..  Mine doesn't blow the 20a breaker it's the 30a the goes..  I will look it over real good when I get back home.
Thanks again
Keith
 
I'll do that, but it's going to be about a week before I can..
Thanks,
Keith
 
If you are tripping the gen set's 30A breaker, you probably have an electrical load problem, not a generator problem.  Each a/c unit draws about 11-13 amps running but a lot more for the second or two when the compressor first kicks in - it can easily jump to 25+ amps for a second. Combined with other loads on the 30A side (fridge, water heater, converter/charger, etc) it is quite likely you are exceeding 30A, at least occasionally.  In all likleihood all your house electrical load is on the 30A leg of the generator output - typically only the rear a/c will be on the other leg.

A 5500 watt generator puts out a total of 5500 watts or about 48-40 amps total. That's not the same total that you get with 50A service from shore power - it's actually about half.
 
Thank you, that makes sense... The 30a breaker only triped when both a/c's were on. Then I would loose the rear a/c.. Maybe there is a problem with the rear a/c?
 
Many if not most 30amp A/Cs will cycle one then the other and not run both at the same time.  At least that's the way I've found them.
 
Keith,
It sounds strange that the 30A breaker would pop and you only lost the rear a/c. In theory, you should have lost BOTH a/c's. Without knowing how they wired the new genset or how (and if) there was a load shedding device installed, it's nearly impossible to diagnose your problem without more info. 
 
The rear a/c should not be on the same breaker as the front a/c, unless of course the RV is wired for 30A only (you need 50A shore power wiring to take advantage of a generator that has two output circuits).  If both a/cs are on the same "leg" of the load center bus and thus both drawing from the same input line (the one fed by the genset's 30A breaker), then yes, it will regularly trip the 30A breaker.  Two a/c s are too much for a single 30A circuit unless the RV is equipped with some kind of load management system that prevents them from running their compressors simultaneously.

So the first question is, what does your shore power cord look like? Is a 4 prong, 50A cord or a 3-prong, 30A cord? That will give us a clue about how your load center is wired.

I'm kind of skeptical of a dealer who would swap a genset merely because another would not start. Smacks of the shade tree mechanic approach that can get you into trouble on complex Rv power systems.  And based on your symptoms I'm thinking he did not wire the Generac properly either. Or at least not in a fashion that lets you use the full 5500 watts of power it produces.
 
Thanks every one...It was a major dealer in Tucson,Az where I bought it.. I was told that it was going to cost more than the Kohler was worth to repair it so they swapped in a used Genrac as a replacement..... Being new to RVing, I didn't know any better.. That was why I picked a large, well known dealer to buy from. It does have 50a shore power and the plug socket for the gen is a 50a.. I know that the a/c's each have ther own breakers on the panel.. The front a/c does keep working when this happens... Maybe bad rear a/c? It's starting to sound like it.. Anyway,  I will look the gen over and take some pics of it when I can get back home in about a week. 
Thanks again everyone.
Keith
 
Do you physically plug the shore power cord into the genset or does it have a transfer switch that handles that internally and automatically?

It sounds as though your a/c's may be wired the opposite of the typical RV. Usually the front a/c is coupled with most other 120 VAC outlets and devices and the rear a/c is by itself. Could be the dealer wired the genset in backwards, though. RV dealer staff are often surprisingly ignorant of things like this.  May I suggest powering up the genset and turning off the genset 30A breaker, then seeing what does and does not work inside the RV?
 
Thanks again for all the help... I will try swtiching off the 30a breaker and checking it out... But when it tripped the front a/c and, I think but not sure, the tv and microwave were working. I just remember loosing the rear a/c. My MH has a 50a plug in the distribution compartment that I plug the shore power cord into.. I do not know if it goes direct to the gen or through a switch. I know it's a 50a plug because I also have the 30a and 20a adapter plugs for the shore power.
Keith
 
I'm getting a bit confused, Keith. At one point you say the front a/c tripped the breaker, then elsewhere you say the rear a/c. Could you clarify which a/c trips which breaker and under what conditions?

Since you plug your shore power cord into an outlet to use the genset, there is no transfer switch.  The 30A breaker on the genset will be wired to one side of the 50A outlet and the 20A breaker to the other (a 50A plug has two "hot" wires, which feeds two separate banks of breakers inside the coach). It's quite possible the dealer reversed the 30A& 20A line from the genset to the outlet, thus reversing how things are powered within the coach.  That's not an issue for the moment, but it could cause some nuisance tripping down the road. Easy enough to fix, though. For now we just need to remember that your rear a/c may be powered from the genset's 30A circuit, rather than the 20A which is the usual source in this coniguration.
 
I am sorry for any confusion... It is the rear a/c that trips the breaker.. If I said the front it was just my typing error... It seems to be only that a/c that is tripping the 30a but have not been home yet to check for sure.
Keith
 
OK, you need to figure out what, if anything, is on the same  bank of circuit breakers as the rear a/c.  When you can, power the RV from the genset and flip off the 20A breaker, leaving only the genset 30A breaker on. Check what works and what does not in that mode, including water heater, fridge, both a/c's and the battery charger/converter as well as any 120V lights and outlets.  You need to ascertain whether the a/c itself is overloading the 30A breaker (an a/c problem) or whether their are other loads on that side as well. That will suggest whether the problem with the a/c unit or somewhere else.

Another way to get a handle on this would be to run the RV off the genset with both genset breakers on, but force the water heater and fridge in LP gas mode, to assure they are not contributing to the load on the genset. Then see if the a/c still trips the breaker.

In either case, I doubt if you have a problem with the generator itself.  If the breaker trips, the generator must be putting out the rated amps. It could be a bad circuit breaker, though. They do get shaky sometimes. And as I said before, it sounds as though the power from the genset is wired backwards from what the normal load balancing would suggest
 
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