Onan QG 2500i LP starts, but dies under AC/Microwave Load

[x5turtle]

Hello All! Just joined the forum as I got my used 2021 Airstream Interstate 6 months ago with very low miles. Generator has about 55 hours on it and the ODO is only shy of 4k. shows very little sign of use.

I used it every weekend to stop here and there and I am not shy is using any part of the car, generator and everything seems to be fine. One thing I did notice is that after the generator warm up, the car shed the AC/Microwave load for 2 min for the generator to properly warm up, which I totally agree!

When I fire up the AC or Microwave after the generator warmed up, the generator hesitate a bit(choke), I would assume it's regulating voltage or whatnot, but correct me if I am wrong. Also, I find the generator not reliable as it turns off after couple hour of use by itself. Fuel is at least 50%, never been very below that, so I have been keeping an eye on that.

The other day, I turn on the generator and decide to use the microwave, the generator starts, warms, but chocks to stop everytime I put microwave or AC load on it. I don't put both load on it at once. I thought it was altitude problem at first, so when I get back below 1k ft, still the same thing.

Any idea what to look into? It did throw me code 13 and code 36, under 2 circumstances. I might try it couple more times to see what kinda code it gives me, but my local airstream dealer said they don't have a mechanic that's qualify for fixing generator even I purchased extended warranty :-(

I am kinda on my own at the moment unless I visit a onan service center.

Thanks for any input!!!

 

[booster]

The propane tank may be in reduced output mode. I won't give no propane, but will reduce the output a bunch.

The reset procedure is pretty easy, so may want to look it up and try it. Be sure to follow it exactly as it is pretty picky sometimes.

 

[x5turtle]

The propane tank may be in reduced output mode. I won't give no propane, but will reduce the output a bunch.

The reset procedure is pretty easy, so may want to look it up and try it. Be sure to follow it exactly as it is pretty picky sometimes.

a little confused, did a google search "airstream propane tank reduced output mode", nothing worthy comes back

when you say propane tank maybe in reduced output mode, are you referring to the generator or you are suspecting my propane regulator is not doing it's job correctly?

Did a little more digging, if the furnace is working correctly, does that mean the propane tank's reduced output mode is not activated?

 

[booster]

click the link for article

reset excess flow valve

Most/many appliances will light, but they are at very low output if the valve is tripped.

 

[booster]

code 13 is low voltage and 33 is overheat so more likely the problem from a quick search.

Check for plugged air vents or other cooling related things.

I saw several posts that mentioned that they had temp sensors fail and cause similar symptoms.

 

[x5turtle]

I just checked again, it's code 36. so what I did is that I stack the appliances, furnace, water heater running together and the water gets to scotching hot and furnace is heating. I think that should rule out the protection mode of tripped valve.

However, I did try to reset the valve, but it's an electronic valve....... so I turn on the LP stove to release the gas, I can't really slowly open the valve because it's electronic, but this is on all airstream coach, not sure if there is a way to target tripped valve.

The generator still runs fine, I did shot a video of it, and when I run AC, it stopped immediately...

gets complicated so fast!!

Video Generator die when AC load just put on

Error Code 36

 

[booster]

I can't read the screens that show on the video as they are out of focus or low resolution.

What is happening to the DC voltage when generator is running and then when you turn on the AC?

Does the AC run and start OK on shore power?

 

[booster]

This may apply and relate to what shows on your video, that I did get cleared up

2021 Airstream Interstate AC

---

This is our first RV and this is what I've learned about AC. Turn on the generator for 2 minutes. Set battery charge at 20% or 2 amps of use. Set thermostat above house temperature. Turn on AC fan which draws about 4 amps for a total of 6 amps. Turn temperatures down to desired level, the compressor comes on and spikes to 31 amps for a second and then settles into 14 amps. If I don't follow this process, when compressor spikes to 31 amps for a second, it shuts down AC and generator. The AC circuit breaker does not flip but I have to turn the circuit breaker off and on. It then does some sort of reset with the AC.

This makes sense, as we have a Magnum with the same remote, and it will shut down from an amperage spike. Yours is shutting off because the charge and power indicators go off on the Magnum. By setting the charge rate very low the spike is minimized because the charger isn't using much.

The Magnum may or may not have 115v for the AC running through it and if it shuts down the generator it could get turned off.

The solution may be to put in an Easy start or Soft start on the AC to reduce the spike.

Seeing if it runs OK on shore using the 10ga RV cord and 30A outlet may tell you.

 

[x5turtle]

I can't read the screens that show on the video as they are out of focus or low resolution.

What is happening to the DC voltage when generator is running and then when you turn on the AC?

Does the AC run and start OK on shore power?

Yes, AC and Microwave runs fine on shore power.

 

[x5turtle]

This may apply and relate to what shows on your video, that I did get cleared up



This makes sense, as we have a Magnum with the same remote, and it will shut down from an amperage spike. Yours is shutting off because the charge and power indicators go off on the Magnum. By setting the charge rate very low the spike is minimized because the charger isn't using much.

The Magnum may or may not have 115v for the AC running through it and if it shuts down the generator it could get turned off.

The solution may be to put in an Easy start or Soft start on the AC to reduce the spike.

Seeing if it runs OK on shore using the 10ga RV cord and 30A outlet may tell you.

I should look into the magnum, but being able to set soft start on AC won't help with microwave also, I think I can't adjust that on the microwave. I haven't done any setting as all are factory airstream setting. it has been fine for a couple months and my friends one are running fine too, so I am kinda isolating problem back to the generator. or maybe I am biased :-(

 

[x5turtle]

I can't read the screens that show on the video as they are out of focus or low resolution.

What is happening to the DC voltage when generator is running and then when you turn on the AC?

Does the AC run and start OK on shore power?

so it was showing 13.6V + 24-27A

looking at this, gives me a feeling that the charging and AC is using too much electricity? but even if I use 14x30 = 420w, microwave or AC is only 1500w, should still be 500 under the 2500w max from the generator, so let say 20% loss, still at 2000w. So maybe I need to isolate charging to test it?

 

[booster]

The quote I gave saying that the Magnum using power is certainly related to problem. If you see a spike of 31 amps, it is likely much higher the that. The wattages are running, not starting and a microwave or AC unit can pull double the running amps, or even a bunch more.

The Magnum will having a setting in a couple of different "max amps" which is for DC amps while charging, so if the starter of genny pulls a bunch and the ignition pulls more, you can go over that setting. I had trouble with the large initial charge was hard for the Magnum to reduce and stabilize, and it would kick out. There is also a setting for the sore power max that is probably set to 30 amps so it probably might allow a big charging surge as soon as the genny starts and that adds to the amp spike on AC. The 2% the quote lists basically tells the charger to not charge and make the spike. A 2500watt generator is only 25 amps so you have no window to 31+ amps of surge. Some generators have larger surge capacity than others, but at startup it can be there or not. Cycling of the AC compressor in use can sometimes give higher surge than startup, even.

Of course the generator has sat a lot, but I am not sure if power is reduced from that like it is in single output ones.

Loaded question here.

Did you change the oil recently? Have you ever checked the oil level in the generator? They have a level sensor in them that will shut them off if low, so when a variable speed motor speeds up and the level drops from the speedup, it could possible shut it off.

If you run it on good shore power of 30 amps you can prove or disprove if the appliances are good turning down the charger per the quote could test if it is the overamp issue. If it is over amping you then would need to checked the generator output and surge capacity and you might need a shop to do that.

Maybe you will get lucky and just be able to push the "charger" button on the Magnum remote to turn off the charger during generator use for high amp appliances. We commonly have the charger off as we hardly ever have shore power and took out the generator years ago. If the charger is off, the indicator light goes off on the remote.

 

[x5turtle]

Resolved, Stealership charged me 270 to get it fixed instead of 1k they claimed because I purchased extended warranty. Which they said they need to drop the generator for servicing.
I think it's a quality issue for 2021 AI generators, as my other 2 friends had the same problems too after I mentioned to them about the issue.
So they claim seal was leaking oil into air filter and soaked air filter, and then need to clean carb. Maybe a mechanic would understand more of the writeup with the parts.
I hope this will guide some of you in the future if you experience the same thing! Thanks for your input!!