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Author Topic: Advice about 12 Volt Radiator Fan on Gen Set  (Read 1776 times)
Dave Siegel
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Stand for something, or you'll fall for anything!


« on: September 03, 2006, 05:28:28 PM »

We have a 10KW Onan stuffed in a bay of our Silversides. In the front and center (just behind the front axle) I have installed a radiator and an 12 volt Flexilite fan (2500 cfm). The air goes through a small tunnel, over the gen set and is exited by a very efficient squirrel cage fan from a central air conditioner, it exists through the floor to the street.  Normal operating temperture for the gen set is about 165 degrees. (We live is South West Florida.)

This arangement has served us well for four years. Last weekend something crawled up into the fan and when I turned it  on it took out some of the fan blades. The rest were lost on the road which in turn destroyed the fan motor. I spent all weekend replacing the fan with a different type of fan (that fit perfectly in the existing shroud) with a little modifying. (I happened to have this fan in the garage, from a previous project.) Today I turned it on for a field test, and the ambient temperature was about 91-92 degrees. The temp gauge started climbing very slowly, but it did climb past 165, 170, 175 (I took about an hour to get there) and came to rest at about 183. I ran it for about an hour and a half with the roof air on, and refrig and some lights on. About the load we normally use.

Should I be worried about this? Or am I just upset because the heat ceiling has been raised by using a different type fan? Oh yeah, I forgot to mention this new fan is a bit quieter.

Thanks for any input, that I can understand.

Dave Siegel

P.S The Help Assist Membership is now up to 90 members. THANKS everyone.

Dave & Jan Siegel    1948 GMC  "Silversides"
            Pinellas Park, Florida
   Dave is Host to the "Help Assist Pages"
  (Free roadside help for Bus Conversions)
Greg Paciga (S.Ga)
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4 years and I'm almost there. N.J. Transits Rock!


« Reply #1 on: September 03, 2006, 06:23:40 PM »

Hey dave. I think I'd consult with Onan about the safe operating temp of the gen set. That would answer all your questions I think. But if you needed a guess I'd say that was too high bro.

Greg Paciga (S. Ga.)

Don't think your going to do a conversion overnight. I did and 4 years later I'm still only 85% done. LOL  Smiley  Smiley

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Pete RTS/Daytona ->'89 TMC 35' 102" 6V92TA 4:10


« Reply #2 on: September 03, 2006, 06:35:11 PM »


I would guess that with your original fan the generator air flow was enough to allowed the generator to operate at the set point of the generator termostat.

But now the replacement fan can no longer maintain a flow that will allow the generator to operate at the termostat set point when the air temp is 91-92.

I can only assume that when the air temp gets hotter than 91-92 - so will the generator - or when the load on the generator increases so will the operating temp.

sorry - I'm sure that's  exactly what you didn't want to hear

perhaps the proof would be - run the generator at no load for a hour - bet it maintains 160 degrees  

Pete RTS/daytona

P.S. - don't I get a little credit for coming up with the idea of the "assist list" ??
« Last Edit: September 03, 2006, 06:38:45 PM by RTS/Daytona » Logged

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