Onan Emerald Plus 5000

Figured i'd follow up on this thread since you all took time to reply with valuable information. I do indeed have a bad 2nd compressor on my basement unit. When I throw that 20amp switch on the gen set and fire up the A/C, about 45 seconds into A/C run time the 2nd compressor tries to start and when it does it makes a horrific squealing noise. I clicked the thermostat off at that point and called it a day. I'm assuming this is why my switch on the gen set has been in this position since I bought the coach. The 1st A/C compressor does still work and will cool the coach, it just takes longer than I always thought it should. Now I know why.

Vibrant93 wrote:

dougrainer wrote:
BOTH 120 Breakers are supposed to be ON all the time. When you have 30 amp service and a 5kw Genset, that bottom 20 amp breaker is dedicated to the 2nd AC compressor. When on 30 amp shore power, there is a Energy Management system that monitors the AMP draw on Shore Power and if you have available amps will allow BOTH AC compressors to run. Some Model Motorhomes do not have an EMS system, but do have a switch that allows you to turn on the 2nd compressor as they expect you to manage your AC amperage. This type system is usually more than 15 years or older. On RV's(30 amp) that have 2 roof top AC units, the same applies. The 20 amp breaker is dedicated to the Rear AC unit and usually there will be a Front/Rear AC switch inside the RV to switch between the Front and Rear AC when on Shore Power. Doug

If you don't have the owners manual click this link

https://winnebagoind.com/resources/manuals/pdfs/Operator2000/00Suncruiser.pdf

Thanks all for the responses. This makes a lot more sense now. I'm really angry that Itasca didn't put a 50 amp service in this coach. We do have an EMS system that shed's power and anytime we are on shore power and are running the air it sheds once that 2nd compressor kicks in. I'm excited to flip this switch and see what happens when on generator power. I'm guessing we'll have colder air when it's 90* and humid OR we'll find out that the 2nd compressor is frozen!

30 amp service was the standard until the 2007 model year. 50 amp was available as an extra cost option from about 2000. As I remember the option on our 2001 Adventurer cost around $300.00.

Keep in mind at the time your coach was new there were very few RV parks that had 50 amp service. When we ordered our 2001 Adventurer the sales person was a bit surprised we wanted the 50 amp service. He said a recent publication by the industry indicated there were less than 15% of parks with 50 amp service. He also made sure we had a 30 amp adaptor to avoid problems.

I'll bet we didn't use the 50 amp service more than half a dozen times in the first 3 years we had the motorhome. It wasn't available most places and was an extra charge in parks that had it.

Fast forward another 3 years and the majority of parks had 50 amp service. It was still an extra cost at all but the higher end parks. Now it's standard at almost every RV park and all the state parks in our area.

Don't be mad at Itasca, be mad at the guy who ordered it that way. Itasca only builds them how they're ordered. :w

dougrainer wrote:
BOTH 120 Breakers are supposed to be ON all the time. When you have 30 amp service and a 5kw Genset, that bottom 20 amp breaker is dedicated to the 2nd AC compressor. When on 30 amp shore power, there is a Energy Management system that monitors the AMP draw on Shore Power and if you have available amps will allow BOTH AC compressors to run. Some Model Motorhomes do not have an EMS system, but do have a switch that allows you to turn on the 2nd compressor as they expect you to manage your AC amperage. This type system is usually more than 15 years or older. On RV's(30 amp) that have 2 roof top AC units, the same applies. The 20 amp breaker is dedicated to the Rear AC unit and usually there will be a Front/Rear AC switch inside the RV to switch between the Front and Rear AC when on Shore Power. Doug

If you don't have the owners manual click this link

https://winnebagoind.com/resources/manuals/pdfs/Operator2000/00Suncruiser.pdf

Thanks all for the responses. This makes a lot more sense now. I'm really angry that Itasca didn't put a 50 amp service in this coach. We do have an EMS system that shed's power and anytime we are on shore power and are running the air it sheds once that 2nd compressor kicks in. I'm excited to flip this switch and see what happens when on generator power. I'm guessing we'll have colder air when it's 90* and humid OR we'll find out that the 2nd compressor is frozen!

BOTH 120 Breakers are supposed to be ON all the time. When you have 30 amp service and a 5kw Genset, that bottom 20 amp breaker is dedicated to the 2nd AC compressor. When on 30 amp shore power, there is a Energy Management system that monitors the AMP draw on Shore Power and if you have available amps will allow BOTH AC compressors to run. Some Model Motorhomes do not have an EMS system, but do have a switch that allows you to turn on the 2nd compressor as they expect you to manage your AC amperage. This type system is usually more than 15 years or older. On RV's(30 amp) that have 2 roof top AC units, the same applies. The 20 amp breaker is dedicated to the Rear AC unit and usually there will be a Front/Rear AC switch inside the RV to switch between the Front and Rear AC when on Shore Power. Doug

If you don't have the owners manual click this link

https://winnebagoind.com/resources/manuals/pdfs/Operator2000/00Suncruiser.pdf

Flipping the switch will not cause any issues with the generator but you should be able to quickly figure out if that breaker powers anything in the coach just by walking around and turning things on!

Dutch_12078 wrote:
If you have 50 amp service, the bottom breaker supplies one of the two hot legs with 120 VAC when on generator power. If you have 30 amp service with two rooftop A/C's, the bottom breaker supplies one of them so both A/C's can be operated at the same time on generator power. There's usually a selector switch that has to be in the correct position to enable both A/C use in that case.

My motor home does not have 50 amp service, it’s a 30 amp coach. Nor do I have two roof to airs, we have a basement air conditioning unit that has two compressors. I’ve always wondered if the second compressor runs when the generator is on. It seems like when we were plugged into 30 amp shore power my load meter reads a lot higher with the air on than it does when I run the generator. If I flip the switch will there be any issues?

If you have 50 amp service, the bottom breaker supplies one of the two hot legs with 120 VAC when on generator power. If you have 30 amp service with two rooftop A/C's, the bottom breaker supplies one of them so both A/C's can be operated at the same time on generator power. There's usually a selector switch that has to be in the correct position to enable both A/C use in that case.