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lcdrdean
02-09-2011, 12:51 AM
I need help with a peculiar problem. Last night we were dry camping and had the fridge running off propane. Since we wanted to watch TV and run the fireplace, I lit off the generator. It started and seemed to run fine so I switched the fridge to electric. The furnace however would not light. When I shut down the generator and lit off the furnace, it worked fine and we had heat through the night. So for a while last night, I ran the generator and watched TV with the fireplace going, but no heat from the furnace. After a couple of hours, the generator shut itself down. When I restarted the generator, it would only run for a few minutes, then shut itself down again. We went to bed with the furnace running running on battery with no problems. This morning, we shut off the furnace, lit off the generator and the fireplace and made coffee with the electric coffeemaker. The generator again ran for a while but then shut itself down.

Any ideas on what might be happening?

danemayer
02-09-2011, 03:39 AM
I had some shutdown problems caused by insufficient propane flow to the generator. It ran fine off one tank, but was erratic on the other tank. One of the hoses needed to be replaced.

newbie
02-09-2011, 04:50 AM
it sounds to me like a propane delivery problem. I have read here about the a faulty sail shutting down the fuel supply which sounds like a possibility here.

John

davidg
02-09-2011, 08:49 AM
The first thing I would do is to check my propane tanks to see how much propane was in both of them, if one is empty or low and the other full I would then swap them around making sure the arrow on the switch over valve is pointed towards the full bottle, then fire up the generator and furnace, if that doesn't work switch the arrow towards the bottle on the opposite side, if that doesn't help could be little trash causing some restriction in the line or the regulator on the switch over valve is not working properly. Bottom line you are not getting enough fuel.
Good luck.

lcdrdean
02-09-2011, 11:17 AM
it sounds to me like a propane delivery problem. I have read here about the a faulty sail shutting down the fuel supply which sounds like a possibility here.

John

What is a "sail"?

branson4020
02-09-2011, 11:31 AM
What is a "sail"?

Its a switch activate by air flow. John is confused about its use though. Not used for sensing propane flow, but for making sure the furnace blower is working.

newbie
02-09-2011, 03:14 PM
I am confused. You would think I would be used to it by now.

Never the less, it certainly sounds like a propane delivery problem since both the furnace and generator are shutting down. I have not had problems with my gas flow so I really don't know much about it but for some reason, I thought the regulator, sensing too much propane flow would shut off the gas thinking there was a leak if too much was going through it. (I know regulators don't think but you know what I mean.)

branson4020
02-09-2011, 03:59 PM
John, I know you're right about some sort of excess flow control in the propane system. I've activated it by disconnectig a line without shutting of the bottles. I don't understand if its part of the valve on the bottles, or part of the regulator itself.

jimtoo
02-09-2011, 07:29 PM
I don't know about the regulator for sure, but don't think it does that.. all the newer bottles have excess flow checks in the valve or neck. In case of line breakage, or accident it shuts it down to a very small flow. Not enough to cook with or water heater use, but maybe enough for a refrigerator

Jim M

lcdrdean
02-10-2011, 01:00 PM
Thanks guys for the information. I will check out the tanks and lines and get back to you.

lcdrdean
04-27-2011, 02:16 PM
Hi all - finally figured out what the problem was. The dealer replaced the regulator, but that didn't help. What I found after doing a lot of research is that when the temperatures get cold, pressure in the propane tanks drop and don't deliver sufficient fuel to the generator. I have found that when it's cold, we can run the generator off a full bottle for about two hours.

YaShouldaGotaDiesel
04-27-2011, 03:42 PM
I was curious to how long an Onan generator will run on a bottle of propane. How long will it run when its warm outside?

danemayer
04-27-2011, 06:18 PM
The Onan manual shows lp consumption at various loads. At full load, the 5500 LP unit consumes 4.7 #/hour. At half load, about 3.4#/hour. That would translate to roughly 8.5 hours at full load, 11.7 hours at half load. That's no doubt an ideal case. As the tank gets low, you're likely to not have enough pressure to keep running. The manual says you'll lose pressure at extremely low temps, but the lp generator is spec'd to run down to 0 degrees F. It also warns of losing power output as temps drop and altitude goes up.

If you're consuming a full 40# tank after 2 hours of runtime, that sounds prohibitively expensive and way above Onan's consumption spec. But if the problem is that you consume 10# of propane in 2 hours and then the generator stops due to low pressure, I'd guess you still have a problem with restricted flow. Gas pressure can be measured to see if the flow meets Onan's Installation Manual spec, which is 9 to 13 inches Water Column (WC) pressure at the genset.

I'd suggest having the dealer take the measurement to see if enough gas is getting to the generator.

lcdrdean
04-27-2011, 07:58 PM
I wish I knew. I haven't had to run it in warm weather yet for any length of time.

newbie
04-27-2011, 09:19 PM
Hi all - finally figured out what the problem was. The dealer replaced the regulator, but that didn't help. What I found after doing a lot of research is that when the temperatures get cold, pressure in the propane tanks drop and don't deliver sufficient fuel to the generator. I have found that when it's cold, we can run the generator off a full bottle for about two hours.

That doesn't seem right. I know you said you found the problem but it still seems like there is a problem.

My generator is gasoline so I don't have any experience with what your are describing but, in my area, a lot of people heat with propane using external, above ground tanks and never have a problem with flow. These are for gas furnaces which consume a lot more propane than a 5500 watt generator. I think you have another problem. Your set up should work even when it is really cold.

Unfortunately I don't know what the problem may be. Good luck getting it working though,

John

lcdrdean
04-28-2011, 03:02 PM
John - The furnace needs less pressure to work than the generator. Our furnace worked fine when the it was freezing outside, but the generator would only run for two hours on the full tank. If I switched to the other full tank the same thing happened. During the day when it was warmer, I could run the generator on the same tank as the night before when the generator shut down. From what I have read, as the temperature drops the pressure in the tank decreases, it gets to a point where it's not enough for the generator. Some people put heat wrap on their tanks to prevent the problem (or pour hot water over the tank). Here's a link that explains it much better than I can: http://www.propanecarbs.com/propane.html

Rodbuster
08-17-2011, 06:46 AM
You mention that the pressure decreases when the temperature drops.
What type of temperature drop are we talking about here? Is the outside temperature 40 degrees, or 30 degrees or 10 degrees, etc.
The reason I'm asking is because I'm thinking of pruchasing an Onan 5500 (propane) for my Landmark Key Largo and I am trying to educate myself on the pros and cons.

Thank you
Rodbuster

2psnapod2
08-17-2011, 07:12 AM
Rodbuster, I have the propane gen in my KL and it works great. Enough power to run both A/Cs and just about anything else. The only draw back I see is that it uses alot of propane, so it is truly a back up power soarce.

Micheal

Rodbuster
08-17-2011, 07:51 AM
Thank you Michael, for your response.

Rodbuster

danemayer
08-17-2011, 08:33 AM
Rodbuster, if you get serious about purchasing the Onan 5500, make sure you get it from someone who you're sure will do the job right. It's been described as a complicated install, beginning with the Generator Prep option that you hopefully ordered from the factory.

Also keep in mind that it's expensive to run in terms of propane use. 12 hours of A/C on the generator will cost at least as much as staying in a commercial RV park overnight.

Rodbuster
08-17-2011, 09:00 AM
Thank you for your comments Dan.
I do have the factory gen. prep. I understand what you mean about the operating cost.
We decided on the gen. a few weeks ago when we traveled up to New Hampshire from Florida. We stayed over in N.C. and also in Pa. The temperatures inside the RV when we arrived at the campgrounds were over 100 degrees and it took a "VERY" long time to get the unit cooled. Made for a uncomfortable evening.
If I would have had the gen., we could have started the AC a couple of hours before arriving.

Rodbuster

danemayer
08-17-2011, 07:44 PM
You know, I also thought that running the A/C for the last 2 hours before we got to the campground would give us a cool living room when we arrived. I tried it on a hot day earlier this summer with poor results.

I'm experimenting with the A/C units a bit. I'm running the front A/C on high fan with the set point at 64 so the compressor doesn't shut off. I have a small fan hanging on the bathroom hallway door to move air from the front A/C into the living room. This misleads the hallway thermostat for the living room A/C so I have that set to 70 or a bit lower with the fan on Auto. The combination is cooling the living room noticeably faster. The bonus is that the living room A/C switches to low speed much sooner reducing the noise level. We set up about 2 hours ago with the outside thermometer reading 97. The living room is comfortable now and the A/C is on low. Outside temp is still at 90.

With the old settings, it would have been running on high for at least another 90 minutes.

hfellis
10-09-2011, 07:54 AM
I am not sure about a propane problem, but when I had this problem it was the transfer switch. Once the switch was bypassed by a certified tech. it ran without any problems. my rv is brand new and I found out there was a recall on the switch. Maybe worth a check.