Additional Onan Genset Cooling?
We just bought a new to us 2006 Winnebago Sightseer with an Onan 4000 genset. The first time we used the generator, all seemed well but after it ran 30-45 minutes it seemed to be having fuel issues. It was in the high 80s to low 90s and the gas tank was full. I stopped and added enough carb cleaner to treat the entire 75 gallons in the tank. We tried it again a day or two later and the unit would not stay running. Again, it was hot out. Luckily the weather changed and the ambient temps dropped to the point we didn't need to run the genset to keep the dogs cool while sitting in parking lots.
On our return trip we got back into hot weather again and I fired up the genset while restocking our supplies. The until ran great for about 30 minuets and then quit, just like it ran out of fuel or I had turned it off. I located a thread on a forum that told how to find the code and it failed on open stator coil (or something like that.
At each event the generator compartment seemed very hot to me. The genset sucks cooling air in on the side and vents out the bottom which can rise right back into the genset compartment.
When I got home I decided to see what I could figure out. I opened the genset compartment and started the genset. It ran for two hours with no issues and the ambient was hot and humid. After the two hours the grass under the genset was scorched and dead. I parked the RV with it's back end over a slope so that the genset was three feet off the ground so it was easy to climb under, so the clearance was greater than normal.
I closed the door briefly and the intake air quickly started rising as the discharge air recirculated. When I say discharge, I am not talking about the exhaust. It is piped out past the RV bumper.
I have read elsewhere that Onan gensets don't do well above 120 degrees ambient and I have no doubt that the compartment was getting above that without the door open.
Yes, the Onan door is in place so cooling air can't short cycle.
Short of leaving the generator door open when parked, the only options I see are:
-install a baffle and grill on the outside compartment door so that the genset has to draw air away from the discharge.
-install some sort of exhaust fan so that the discharge air is pulled away from the enclosure.
-install a fan to blow air into the compartment through the compartment door.
I am an HVAC tech, so I know a little about things like this. It floors me that a genset would be factory installed in a manner that allows hot discharge air to rise right back into the genset.
Every A/C unit I have worked on in 31 years requires a great deal of free space past the discharge as well as the intake.
Any similar experiences or cures?
On our return trip we got back into hot weather again and I fired up the genset while restocking our supplies. The until ran great for about 30 minuets and then quit, just like it ran out of fuel or I had turned it off. I located a thread on a forum that told how to find the code and it failed on open stator coil (or something like that.
At each event the generator compartment seemed very hot to me. The genset sucks cooling air in on the side and vents out the bottom which can rise right back into the genset compartment.
When I got home I decided to see what I could figure out. I opened the genset compartment and started the genset. It ran for two hours with no issues and the ambient was hot and humid. After the two hours the grass under the genset was scorched and dead. I parked the RV with it's back end over a slope so that the genset was three feet off the ground so it was easy to climb under, so the clearance was greater than normal.
I closed the door briefly and the intake air quickly started rising as the discharge air recirculated. When I say discharge, I am not talking about the exhaust. It is piped out past the RV bumper.
I have read elsewhere that Onan gensets don't do well above 120 degrees ambient and I have no doubt that the compartment was getting above that without the door open.
Yes, the Onan door is in place so cooling air can't short cycle.
Short of leaving the generator door open when parked, the only options I see are:
-install a baffle and grill on the outside compartment door so that the genset has to draw air away from the discharge.
-install some sort of exhaust fan so that the discharge air is pulled away from the enclosure.
-install a fan to blow air into the compartment through the compartment door.
I am an HVAC tech, so I know a little about things like this. It floors me that a genset would be factory installed in a manner that allows hot discharge air to rise right back into the genset.
Every A/C unit I have worked on in 31 years requires a great deal of free space past the discharge as well as the intake.
Any similar experiences or cures?
