Kohler 8.5RES LP gas installation?

mkaiserco

(sorry for the cross-post, but I meant to put this in the off-grid area)

I know I should get a "gas guy" to do this, but I'm on a private island off the coast of New Brunswick--and it would cost a fortune to get one out here.

My trusty Onan 7.5 LP genset has given up the ghost, so I've ordered a Kohler 8.5RES to replace it. I'm looking at the Kohler installation manual and trying to figure out what I need to do.

The Onan is fed by a flexible pipe going into a solenoid valve that then goes into something called a "Garretson Secondary Gas Regulator", before connecting to the flexible pipe on the Onan. This installation WAS done by a professional 17 years ago.

It looks to me like the Kohler has a built-in solenoid valve, so I won't be needing the external one.

But what I'm trying to figure out is whether I still need the Gas Regulator, or whether I can simply connect the flexible pipe to the Kohler 1/2" external connector.

The reason I don't know the answer, of course, is because I know absolutely nothing about LP--which is an excellent reason why I shouldn't be attempting this myself.

But I figure how hard can it be?

Any and all suggestions are welcome.

Oh, and there is also something called a "dry fuel filter" in the line, ahead of the Gas Regulator. I figure I'll just leave that in, but should I open it and clean it?

Thanks.

Mike

mkaiserco

Kohler 8.5RES LP gas installation?

I know I should get a "gas guy" to do this, but I'm on a private island off the coast of New Brunswick--and it would cost a fortune to get one out here.

My trusty Onan 7.5 LP genset has given up the ghost, so I've ordered a Kohler 8.5RES to replace it. I'm looking at the Kohler installation manual and trying to figure out what I need to do.

The Onan is fed by a flexible pipe going into a solenoid valve that then goes into something called a "Garretson Secondary Gas Regulator", before connecting to the flexible pipe on the Onan. This installation WAS done by a professional 17 years ago.

It looks to me like the Kohler has a built-in solenoid valve, so I won't be needing the external one.

But what I'm trying to figure out is whether I still need the Gas Regulator, or whether I can simply connect the flexible pipe to the Kohler 1/2" external connector.

The reason I don't know the answer, of course, is because I know absolutely nothing about LP--which is an excellent reason why I shouldn't be attempting this myself.

But I figure how hard can it be?

Any and all suggestions are welcome.

Oh, and there is also something called a "dry fuel filter" in the line, ahead of the Gas Regulator. I figure I'll just leave that in, but should I open it and clean it?

Thanks.

Mike

BB.

Re: Kohler 8.5RES LP gas installation?

Its OK--I just moved them together.

-Bill

GreenerPower

Re: Kohler 8.5RES LP gas installation?

mkaiserco wrote: »

...But what I'm trying to figure out is whether I still need the Gas Regulator, or whether I can simply connect the flexible pipe to the Kohler 1/2" external connector.

Look at the Onan spec to see what's the gas pressure it can take in (usually in inches of water column). Also look at the spec of that external gas regulator to see what's its output pressure. That gas regulator is probably to bring down the gas pressure from the source to a level that the generator can take.
GP

icarus

Re: Kohler 8.5RES LP gas installation?

The answer as to whether or not you use the Garritson regulator may depend on whether or not the entire system is designed to run on vapor or liquid. 7.5kw is sort of at the threshold where it might need to run on liquid.

I suggest you post your question here, as there are some very smart folks regarding gen-sets and fueling them. (Follow the thread backwards and you will find some pretty good Kohler LP info). http://www.smokstak.com/forum/forumdisplay.php?f=25

Good luck and welcome to the forum.

Tony

PS

Just out of curiosity, what happened to the Onan. What model/version. Repairs are not usually terribly expensive.

solorone

Re: Kohler 8.5RES LP gas installation?

I really got interested in this thread, so I had a look around, and was shocked at the fuel consumption. What made you decide on using propane?

I remember looking at this 25 years ago, nothing much has changed in that area.

mkaiserco

Re: Kohler 8.5RES LP gas installation?

Why did I decide to use propane? Hmm, good question. It was 17 years ago when we built the cabin on the island.

My best answer is, I guess, simplicity. The house is solar powered, primarily. We use the generator only for backup--cloudy stretches. Other propane-powered appliances are the fridge, the oven, the space heaters, the clothes dryers, and the tankless hot water.

To have installed a large diesel tank here would have been one more thing to site--and we would have had to arrange for delivery.

Possible of course, but all in all, I don't use the generator enough to justify (in my mind) another fuel source over here.

Make sense?

Thanks to all for your suggestions regarding the regulator. I'm heading over to smokstak to see what they have to say over there.

Mike

icarus

Re: Kohler 8.5RES LP gas installation?

Propane is clean, and it doesn't spill when you transport it.

It has fewer btus per unit of volume than gasoline or diesel, and the engines it powers are significantly less fuel efficient.

That said, for occasional service in remote locations, it make a great, clean, transportable fuel. You never hear about a propane spill fouling the land or the water like a gasoline or diesel spill. Assuming you have access to supply, it is a pretty good fuel for the uses mentioned.

Tony

mkaiserco

Re: Kohler 8.5RES LP gas installation?

Tony asked what happened to the Onan.

Another good question.

First of all, it's a 7.5JB FL, serial number L930527584, spec 306440.

The short answer is I don't know. When I started it up this summer, I ran it for about three hours, then shut it off. I was topping off the batteries in our solar bank.

Then a few days later when I started it up, it shut off after about 10 minutes. I wasn't near it when it shut down, so I didn't hear anything unusual.

But after that, it would never stay running longer than 10 minutes, and I'm hearing a "metallic" noise from the end of the enclosure where the cooling fan intake is. I've talked with an Onan service tech, described the symptoms, and even sent him videos with sound. He has no idea what the problem is, but it would cost me at least $800 just to get him to come out to the island and check it out--mostly travel time.

Then it would take who knows how much time and money to repair.

My (uneducated) guess is it's a bearing--either in the fan or the motor itself.

So while I might be able to get it repaired and running for another 17 years, I'm thinking the "safe" thing is to buy a new Kohler for $3,000 and install it myself.

We'll see.

Mike

icarus

Re: Kohler 8.5RES LP gas installation?

Go to the Onan section of Smokestack and post the symptoms. There are some pretty sharp folks there. You might find a simple fix, and then have it for emergencies. I'm not real familiar with that model, but a "metalic" sound is probably not good news. My guess is that it may have a carbon build up, or as you suggest, a bearing failure.

I assume that you have checked/changed the oil. Does this have a ducted out flow fan (vacuflow) or an inflow fan? Ducted fans have been known to get some junk in them.

Good luck with the Kohler.

Tony

mkaiserco

Re: Kohler 8.5RES LP gas installation?

Thanks for the suggestion, Tony. Once I get the Kohler installed, I'll begin that conversation on smokstak.com.

Mike

chevenstein

Re: Kohler 8.5RES LP gas installation?

Gas fitting isn't hard, per se, but the cost of failure is quite high. Remember these things and you you'll be off on the right foot:

- LP is heavier than air and likes to pool on the floor or low areas on the ground. It's also oxygenated at this point so the explosion potential is huge.
- All but the yellow teflon tape is not designed for gas fitting and should not be used. When connecting threaded iron pipe use either pipe dope or pipe dope and gas tef-tape and be sure to use the correct wrench for the pipe size you're fitting (to get it tight enough).
- Flared connections can leak if there's ANY irregularity on the brass inner fitting surface that will interfere with the seating of the flare (this is the conical part of the fitting that goes into the flare nut). A bunch of fittings rolling around in a tool box will eventually nick and ding each other up resulting in this problem.
- ALWAYS test your work for leaks with a manometer (soapy water will not always find everything)
- Build yourself a manometer if you don't have one and use it both to set your regulator (if the genset is vapor fueled) and to test for leaks. You can make one with some plastic tube, a piece of 2x6, and some romex wire staples.
- Code has all sorts of setback and distance requirements that you probably won't have to prove to anyone when you're off grid and remote, but they exist for good reason. For example, keep your regulators at least ten feet away from ignition sources as regulators can and will leak if their diaphragms rupture. On a vapor genset with only 1/2" inlet it might not be practical to locate the secondary regulator so far away; in this case pipe the regulator vent (usually a screened opening in line with the inlet) away from the genset.

Treat LP with the respect it's due and work methodically and deliberately and you'll be OK. Best of luck.

icarus

Re: Kohler 8.5RES LP gas installation?

Very nice Chev,

I would add one thing. Instead of testing for leaks with a manometer, which only requires the pipe to hold 13" WC or about 1/2 psi, the real way to test gas pipe is to disconnect or valve of any regulated appliance and regulators (so that you are pressurizing only pipe and fittings, not appliances and regulators to be clear as mud). The install a tee with a 0-30 psi gauge in the tee along with a schrader valve (tire inflation valved). Pump the entire system up to at least 15 lbs, and let it stand at least 15 minutes. If the gauge doesn't drop then you know you have it tight. I personally prefer 30 lbs, which is about 2 times the required pressure for regulated lp gas.

And as Chev suggests, pay particular attention, and never use teflon tape that is not rated for gas. I prefer dope in any case. ( oh wait, that didn't come our right!) (I second the idea of piping regulators away from ignition sources) (Lp gas detectors are probably a good idea, as they are fairly reliable and cheap).

T