Generator Conversion

[highland512]

I have a opportunity to bring home a nice little generator. The generator is an Onan unit set up to run on natural gas and produces 15kw constant. My problem is I dont have NG at the house but I do have a 1000 gal lp tank that supplies the heater, stove, and water heater in house. What would have to change to get the NG unit to run on lp? Im guessing the orifice would have to be swapped out in the regulator? All of the research I have done on the goggles only seems to give me results on converting a gasoline unit to NG or lp.   

[slip knot]

I "Think" it would just need the demand regulator changed out. Go over to the Smokstak.com site and look into their Onan page. lots of good info there.

15KW will run a lot of items but lots of gas too.

[highland512]

We rarely loose power but when we do it’s usually during a winter storm and could be without power for god knows how long and how cold it could be. Last time it was 6 hours and it was -2 with a 20 mph wind. Luckily the house only dropped 6*. My main thing is the heat then needing the well pump to run.

[bonneyman]

If I recall when we changed a gas furnace to run on LPG from Natural we put in a smaller orifice and removed the regulator spring in the gas valve, as the regulator for LP gas is on the tank itself.

Natural runs at 3.5 inches of water colomn, LP gas is 11 inches. Plus, LP gas has more than twice the heat energy compared to natural (2500 BTU's per cubic foot compared to 1200), so, LP orifices are ALOT smaller. On furnaces. Can't say I know for sure on internal combustion engines.

[highland512]

I did some more inspection on this generator while we where back home for thanksgiving. Its an Onan 5.0cck, which seems to have a cult like following on smokestack. I have been reading over there but have still not been able to get an answer on my question of ng to lp, I guess I will post and find out. Turned out this unit is only a 5 kw not the 15 kw I was told but I think it will be plenty to run the house since I have lp heat, lp hot water heater, lp cook top /oven, and newer appliances. It is a neat little generator, looks to be made in the sixty's or seventy's and only has 100 hrs on it and the operating rpm is only 1800 and has electric start. Im going to dig it out from its retirement at christmas and haul it home, my main concern now is I think it has been sitting for around 25 years but it has been stored in a dry building. Pictures to follow later in the month 

[slip knot]

Those old CCKs are all but bullet proof. I've got one with several 1000 hours on it. use it at the farm to run the water well. 5KW should run a good deal at your house with gas heating.

 it is electric start but doesn't have an external starter, uses part of the generator as the starter. Think big hot battery, weak battery and grinding it down is hard on the rotor. the slip rings will need to be cleaned up and the brushes freed up. Also check for rodent damage and cracked/broken connectors. those onans have a bad habit of that. The engine speed controls voltage and hertz. set the governor to maintain @62 hz with no load.

I don't have much experience with NG/LPG sets but it shouldn't be too complicated to convert. Several companies make conversion kits that are @$200 or so and that's a complete kit from gasoline to NG. should be easy enough to make it work. post you model and serial over on Smokstak and they can direct you to the operations manual. that will possibly have the info you need for LPG/NG conversion.

[highland512]

Well according to the gents on smokestack (they are REALLY into these cck's it seems) the change between burning NG or LP is as simple as closing the gap on a bolt thats used in place of a orifice. Lets hope so, that would make getting this machine into service quick and easy baring no problems from sitting in storage.

[fatfillup]

That actually makes sense as you are burning less volume of gas