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apr67

Tallahassee, Florida

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Posted: 07/23/19 12:36pm Link  |  Quote  |  Print  |  Notify Moderator

shastagary wrote:

from the installation manual
Quote:

Hot Air Recirculation Test A representative installation of the genset must be tested to determine that the genset will not overheat due to recirculation of hot air back into the genset.
8.4 Test Requirement The rise in inlet air temperature over ambient air temperature must not exceed 15°F (8°C). A rise in inlet air temperature indicates hot air recirculation. If the rise exceeds the requirement,steps must be taken to reduce recirculation to an acceptable level.


I am wondering if my multi probe BBQ thermometer is enough for this job, I'm going to try it and see as soon as the rain (cooler weather) moves away. I think the problem is recirculation on my unit with the same exact issue as the original posters.


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wopachop

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Posted: 07/23/19 12:50pm Link  |  Quote  |  Print  |  Notify Moderator

What a bummer man. You spent a couple thousand at cw and an Onan technician came out twice?

I wonder if there is paper work documenting his Hot Air Recirculation Test? If not maybe you can recoup some dinero.

map40

Florida

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Posted: 07/23/19 01:23pm Link  |  Quote  |  Print  |  Notify Moderator

When you shut down the generator the temperature shoots up because there is no more air circulation and you have a lot of heat in the engine. This stands true in any internal combustion engine.
What I do is I leave the generator running for 5-10 minutes with no load before shutting down so it can cool down and then I shut it down.
If your generator has poor air cisculation, you need to let it cool down with no load while running. I had a 5500 that the previous owner told me to be carefull because he had that problem. Because I was doing this I never had an issue restarting it.


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joebedford

Finally back home in the north

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Posted: 07/23/19 01:53pm Link  |  Quote  |  Print  |  Notify Moderator

Don't run it with the compartment door open or the generator cover off. That reduces airflow and promotes overheating.

CoachFiver

Upstate NY

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Posted: 07/23/19 04:26pm Link  |  Quote  |  Print  |  Notify Moderator

If I run my generator with compartment door shut it will shut down in 70 degree weather. There is just not enough of a baffle separating the exhaust side air and the intake side air. Going to try my homemade sheet metal heat deflector this weekend.

map40

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Posted: 07/24/19 05:39am Link  |  Quote  |  Print  |  Notify Moderator

CoachFiver wrote:

If I run my generator with compartment door shut it will shut down in 70 degree weather. There is just not enough of a baffle separating the exhaust side air and the intake side air. Going to try my homemade sheet metal heat deflector this weekend.


The only real problem is the generator cover. It is designed to direct airflow. One of the first times I worked on a generator I was running it without the cover and burned out the exhaust because the airflow cools it down. No cover means the air will follow a different path.
If the problem is with the compartment door that is a coach manufacturer problem and could very well be an issue. All 3 of my Jaycos 31XLs melted the compartment door after 1000 hours. Still, always let the generator cool down running before turning it off.

joebedford

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Posted: 07/24/19 07:05am Link  |  Quote  |  Print  |  Notify Moderator

One of the problems with the compartment door is that if he's already having problems with airflow, leaving the door open could let combustion products get into the rig.

wopachop

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Posted: 07/24/19 10:40am Link  |  Quote  |  Print  |  Notify Moderator

Seems like a lot of the newer toyhaulers I see have a open screen over half the compartment door.


We boondock in 110F and often see compartment doors held oven partially with a stick.

Not sure if those people have actually taken measurements to confirm it helps cool the genny.

bounder39zman

SC

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Posted: 07/27/19 05:33pm Link  |  Quote  |  Print  |  Notify Moderator

I run a mobile generator shop (in the South!), and fight this battle all summer long with Onan HGJAB and HGJAE (commercial version). Several things going on here. 1) fuel pumps get hot and quit pumping, will usually display fault code "36", Control board circuit that powers fuel pump gets so hot it quits sending power to pump, again shows code "36". The gasoline we have now seems to have a lower vapor point, so it is "boiling in gen compartment and carburetor (i.e. vapor lock!). Onan ( Indiana Distributor) has designed and made available several kits to install and deflect hot discharge air away from the cooling air intake. This has helped in a number of cases, and seems to be best solution, short of moving to Alaska. The EFI versions do much better, as fuel is under high pressure from the supply pump, but they too seem to run very hot in high ambient temps.

onrecess

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Posted: 07/27/19 06:23pm Link  |  Quote  |  Print  |  Notify Moderator

wopachop wrote:

What a bummer man. You spent a couple thousand at cw and an Onan technician came out twice?

I wonder if there is paper work documenting his Hot Air Recirculation Test? If not maybe you can recoup some dinero.

THAT problem was the fuel pump. They replaced the carb, and then said they were going to rebuild THAT! All it was, the whole time, was a fuel pump. I fixed it in ten minutes, under $100.


Tom Anderson
2005 GeorgieBoy 35

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