Common problem to 7kw model #5240?

[Duane Pulliam]

Kelly:
Is the problem I have with the 7kw mod. #5240 sputtering on startup for a few seconds before running up to full speed common with all 5240s? Everyone I know around here with the same unit has the same problem, only most are worse than mine. Does this eventually clear up with a some run time on the genset? Is it because the 5240 does not have a choke?

[Kelly Myers]

Hi Duane,

Remember this thread?

http://zillerelectric.com/forums/showthread.php?t=77

I'm guessing the plug didn't help the starting?

[Duane Pulliam]

Hi Kelly:
I was just waiting for your reply to my gas supply question and thought I would re-ask about if this is common or not. Yes the plug did help the starting but I still have to get a Hz meter and reset the gas regulator and gov. settings so it runs smoothly. I am still curious, since you are a dealer, do you see this as a frequent problem with the 7kw units?

[Kelly Myers]

Hi Kelly:
I was just waiting for your reply to my gas supply question and thought I would re-ask about if this is common or not. Yes the plug did help the starting but I still have to get a Hz meter and reset the gas regulator and gov. settings so it runs smoothly. I am still curious, since you are a dealer, do you see this as a frequent problem with the 7kw units?


We sell (3-5) 7kws a day. They are very popular where AC units are not needed. I get phone calls about them being broken 3 or 4 times a week. After I explain to them the fuel requirements, and how to set the fuel regulator and governor (page 12-13 of your manual), they all end up working. The 7kw do require being tuned in.

What is the total footage from the gas meter to your generator?

[Duane Pulliam]

Thanks for your response. My gas line from the meter is 1" and runs approx. 25' to the furnace. At about 18'-20' in from the meter, I teed into the 1" with 3/4". The 3/4" runs about 19' to the generator. That is - approx. 20' of 1" then 19' of 3/4".

[Kelly Myers]

So we have a total of 40', and I will figure you have four 90 degree fittings that count for 3' per fitting.

So we have aprox 52'

You can flow a total of 91,000BTU's from the meter to your generator with that pipe.

At the T you installed, you have 194,000 BTU's availble for both the furnace and the generator. If your generator is running, you may only have 50k-60k BTU's availble at the generator.

This generator will never run properly with this fuel setup.

If you do a seperate run from the gas meter to the generator, and use 1" pipe the whole way, you will be able to flow 144,000 BTU's, and the generator will then have enough fuel to run.

[irq3]

Here is an interesting blog about a generator improperly installed (fuel supply) and then corrected:

http://www.indovina.us/~mai/generator/

[Duane Pulliam]

Yes that is an interesting blog. However, in my situation, my existing gas meter is rated for 390,000 BTU/hr. My total load, including the 7 kw generator, is 255,000 BTU/hr. The gas company says they maintain a 7" WC. My generator requires a 5-7" WC. The main gas line into the house is 1". The gas supply tables that can be found on the internet show that I have more than an adequate supply to the generator for the size and length of my gas line to the generator, furnace and water heater. After the initial 2-4 seconds of sputtering upon startup, my generator runs up to full speed and runs fine. It seems that I just need to make some adjustments to the regulator/govenor/3/4" air port to get things fine tuned. Just haven't had a chance to play with it yet. If I put the 3/4" plastic plug in the air cleaner box, the generator will fire right up but then surges because the mixture is too rich. I have to play with that arrangement. All of the other folks in the area that I know of who also have the #5240, 7 kw models have the same or more severe problem at startup. It seems that Generac could do a better job of setting these things up at the factory. After all, they are pre- packaged for the home owner to self install.

[Duane Pulliam]

Also, after my generator has run and shut off, it will start and almost instantly run up to full speed without any hesitation, even if it's been a day since the generator has run. But if it sits all week between exercising periods without running, it will sputter for 2-4 seconds before running up to full speed. A friend of mine has installed two of the same models for his inlaws and they both have the same, only more severe problem. And they are both located only about 3' from the gas meter and are connected with 3/4" pipe, so gas supply is definitely not the problem there either.

[Kelly Myers]

Also, after my generator has run and shut off, it will start and almost instantly run up to full speed without any hesitation, even if it's been a day since the generator has run. But if it sits all week between exercising periods without running, it will sputter for 2-4 seconds before running up to full speed. A friend of mine has installed two of the same models for his inlaws and they both have the same, only more severe problem. And they are both located only about 3' from the gas meter and are connected with 3/4" pipe, so gas supply is definitely not the problem there either.

If it starts up on the first series of crank cycles, I wouldn't worry about it. I believe its programmed for 7 start attempts before it fails into over crank.

If its starting on the first crank cycle of aprox 10 seconds, there is nothing to worry about. Its just moving fuel through the regulator to the engine.

[Duane Pulliam]

Thank you for responding Kelly. Yes, it cranks for about 2-3 seconds then starts and sputters for another 2-4 seconds before run up to full speed. Then everything is fine. I did the install the first week in Jan. When I did the power transfer tests I checked to make sure the furnace came on and ran OK. To verify that I had enough gas supply I even checked the flame on the furnace burner with both the generator running and off and couldn't see any difference in the flame either way or any difference in the way the generator ran. I agree that I should just leave it alone instead of fooling around with it. Thanks again for your help.

[Kelly Myers]

Thank you for responding Kelly. Yes, it cranks for about 2-3 seconds then starts and sputters for another 2-4 seconds before run up to full speed. Then everything is fine. I did the install the first week in Jan. When I did the power transfer tests I checked to make sure the furnace came on and ran OK. To verify that I had enough gas supply I even checked the flame on the furnace burner with both the generator running and off and couldn't see any difference in the flame either way or any difference in the way the generator ran. I agree that I should just leave it alone instead of fooling around with it. Thanks again for your help.

I've personally installed over a hundred 7kw units. Every single one will do what you're saying happens to yours. Don't worry about it, its just a delay in fuel.

[Gman1]

Hi Y'all, First post.

I have found that the 7 kw does not have enough vacuum on the fuel solenoid to open it. That is why the plug in the air box helps. You can squeeze the rubber hose on the air cleaner and as soon as it cranks release it. It will then run fine. I have found it necessary to "tweak" the spring inside the regulator on the diaphram. I have also found that they work better on the low end of the 5-7 "wc. I hope this is helpful.

[Duane Pulliam]

Gman:
Thanks for the response and information. What exactly do you mean by "tweak the spring inside the regulator on the diaphram"? Do you mean the gas regulator in the back right hand corner of the unit where the gas line enters the cabinet? What did you do to tweak the spring? Thanks again.

[Gman1]

By "tweak" I mean cut a round off of it and then re-stretch it...to weaken it so the diaphram can pull the valve open more easily. You need to understand that if you "tweak" it too much, you will render the safety function of the demand regulator useless. You will still have the fuel solenoid, but if it were to leak past the seal and the demand spring were weakened you could leak gas into the airbox. I have done this on a couple of units and they now crank just like the twin cyls.