Dreaded 3-6 Generator code

[Hittntherooad]

I had recently read numerous threads on the Onan generator shutting down from overheat while driving down the highway. On the way to Williamsburg last weekend the dash AC just couldn't keep up. I stopped and started the generator and turned on the coach AC. It was doing pretty good. We stopped at a shopping center before heading to Anvil Campground. I pointed my heat gun on the asphalt in the shopping center parking lot. 145 degrees. The generator shut down before I could get into the campground and get hooked up. Also glad I installed the second unit in place of the fantastic fan in the bedroom. With 3 kids running in and out all weekend, we needed it.
After reading some of the threads for remedies, it looked like some added a vent in the generator door or put a pipe to collect air from the front grill and direct it to the generator intake. I opted for the second. Hooked it up. Drove 40 miles yesterday in 96 degrees. Generator kept running the whole time. Will hold off on the vent in the door for now but I can see the problem is the cooling air intake on the generator is only 1 1/2 " from the compartment door when shut. Hopefully collecting the air from the grill will be cooler and solve the problem. About $40 in material. 6" semi rigid flexible duct.

[Hittntherooad]

Front picture intake

[Hittntherooad]

For those wanting to do the door vent, I found this on the Foest River forum. This vent is designed specifically for the Onan. The key is the rubber boot isolating the outside air from the hot air under the coach.

[Hittntherooad]

Outside vent

[blw2]

Originally Posted by Hittntherooad

Outside vent

I'm very interested in that rubber booted vent. Can you tell us more, or link to that other discussion?

I recently put a smaller vent in my door, that didn't completely solve the problem. i can tell that it's still pulling a huge amount of air from places other than the vent.... so that means the hot air from under the coach.

I considered an air scoop, but that would only help really when driving, and may result in unintended consequences from too much ram air

Here is the vent I found at West Marine and installed

[Hittntherooad]

When I called Thor, they didn't have a clue for this vent. They wanted to send me a door with a vent in it. I told them it wouldn't do any good with just a vent as the hot air coming from underneath would still get sucked into to the intake of the generator. I found this at this thread on Forest River forum. Generator Mods - Forest River Forums
Camping World in Myrtle Beach where I bought my Ace is also a Forest River dealer and the guy that handles issues like this ordered me one through Forest River. Thors answer to me was I live in area that the temperature exceeds the Onan generator requirements. What the heck kind of answer is that? Do they think people up north don't drive down south?
Anyway, I have one on the way and this vent is made specifically for the Onan generator. I feel good that along with my duct I ran from the front and this vent will cure my problem. We probably will not be camping a lot in these extreme heat conditions but want to be prepared if we do.

[Chance]

Originally Posted by Hittntherooad

....cut... Thors answer to me was I live in area that the temperature exceeds the Onan generator requirements. What the heck kind of answer is that? Do they think people up north don't drive down south?
....cut....

Are you suggesting the generator should work with cooling air at 145 F?


In fairness, there will be times when temperature off pavement will exceed the Onan's generator rating. In Houston when I got stuck in bumper-to-bumper traffic on the 610 Loop, the ambient air temperature my car's sensor indicated was well above 120 F, and that was at front grille area. It's not only the intense heat from sun, but all the cars around that are also burning gas and giving off heat.

[Hittntherooad]

Originally Posted by Chance

Are you suggesting the generator should work with cooling air at 145 F?


In fairness, there will be times when temperature off pavement will exceed the Onan's generator rating. In Houston when I got stuck in bumper-to-bumper traffic on the 610 Loop, the ambient air temperature my car's sensor indicated was well above 120 F, and that was at front grille area. It's not only the intense heat from sun, but all the cars around that are also burning gas and giving off heat.

Not saying that. Have you looked at how close the cooling air intake is to the bay door? 1 1/2" maybe add the fact that it is enclosed with all the heat from the engine and exhaust being sucked right into it. I have to believe that installing will be some help in keeping the generator operating when temps are close. Some have even said on other forums that their doors are bubbling from the intense heat. Others have reported no problems after installing the vent. Forest River even puts the vent on their newer models so apparently they see it as a problem.

[Chance]

Originally Posted by Hittntherooad

Not saying that. ....cut.....

I know. It was a poor attempt at humor on my part.


I think "part" of the problem may be that these little air cooled generators were not originally designed specifically to run under relatively high load while traveling on the highway. They do well most of the time, but under severe conditions it's going to be tough to keep them from overheating.

If we look at a typical 4,000-watt generator powering a 15,000 BTU/hr standard air conditioner on a hot day, it will be running at close to 50% load. And if the owner doesn't manage other loads like fridge, battery charger, and possibly water heater, the generator may end up loaded down and thus more prone to overheating.

If I were using the generator to power an AC while driving on an unusually hot day, I would try to minimize other loads. The more power it has to make the hotter it will get.

I personally prefer not running a generator while driving (have never needed to) but given the need, I think your solution to duct cool air is excellent. If it works on race cars to help cool brakes then it can't hurt with a generator. The side vent idea looks great too.

[penguin]

Originally Posted by Hittntherooad

For those wanting to do the door vent, I found this on the Foest River forum. This vent is designed specifically for the Onan. The key is the rubber boot isolating the outside air from the hot air under the coach.

Looks like the best part for the job. Do you have a link where it could be purchased.

[blw2]

I believe they posted they had to go to a Forest River dealership.

I'm thinking it won't be too hard to modify my little vent, using some garage door weather stripping, or something similar. That brush stuff that Onan is using in the genny housing would be ideal

[Hittntherooad]

Originally Posted by Chance

I know. It was a poor attempt at humor on my part.


I think "part" of the problem may be that these little air cooled generators were not originally designed specifically to run under relatively high load while traveling on the highway. They do well most of the time, but under severe conditions it's going to be tough to keep them from overheating.

If we look at a typical 4,000-watt generator powering a 15,000 BTU/hr standard air conditioner on a hot day, it will be running at close to 50% load. And if the owner doesn't manage other loads like fridge, battery charger, and possibly water heater, the generator may end up loaded down and thus more prone to overheating.

If I were using the generator to power an AC while driving on an unusually hot day, I would try to minimize other loads. The more power it has to make the hotter it will get.

I personally prefer not running a generator while driving (have never needed to) but given the need, I think your solution to duct cool air is excellent. If it works on race cars to help cool brakes then it can't hurt with a generator. The side vent idea looks great too.

No problem, yes definately if necessary to run AC while driving is to keep as little as possible load on the genny.

[Hittntherooad]

Originally Posted by penguin

Looks like the best part for the job. Do you have a link where it could be purchased.

Look at post #6 and click on the link. It has part numbers for both pieces.

[penguin]

Originally Posted by Hittntherooad

Look at post #6 and click on the link. It has part numbers for both pieces.

Thankyou, I see the part numbers, so should I just call forest river and give them the part numbers and purchase the vents from them or are there other retailers that I can buy from.

[Hittntherooad]

Originally Posted by penguin

Thankyou, I see the part numbers, so should I just call forest river and give them the part numbers and purchase the vents from them or are there other retailers that I can buy from.

Camping World where I bought my Ace sells Forest River also so the guy ordered one for me. Those part numbers do not show up on any Thor inventories but show up on the Forest River. You will have to order from a dealer.

[blw2]

what was the price for that Forest River part?