LP Generator Auto Start Issues

56napco · October 2019

Hello- I am new to the forum and relatively new to solar/battery systems and LP fuel systems. Currently we have a Honda Eu3000is generator converted to LP gas and is hooked up to a Magnum Energy ME-ARC controller. The generator is used as a backup or supplement to the solar panels and not the sole energy source to charge the batteries. The biggest issue is being able to rely on the auto start function and the generator starting on its own. The generator is hooked up to a 500 gallon LP tank, there is a regulator on the tank and then it is fed to the generator regulators. On the generator there is a small Precimex regulator (similar to a gas grill regulator size) which is plumbed to a Garretson KN regulator which feeds the carburetor. I'm not very familiar with LP fuel systems so why it is setup this way is beyond me. When the controller commands the generator to start you have to manually press the primer button on the regulator in order for it to start while the generator is cranking, if you don't use the primer button it will not attempt to start. It doesn't need much priming either, just a touch of the button and it will start, too much and it floods. Once the generator gets started it runs great with no issues at all. When it was converted it was bench tested using a 20lb grill tank and started on the first try each time but since plumbing it to the 500 gallon tank it needs to be primed. I have a couple pictures of the regulator setup to make it clearer. We've tried eliminating the small regulator, by passing it completely and plumbing into the regulator that is on the side of the house as well, neither allowed it to start that way either. Could the load block need to be adjusted or is there something else not set correctly?

mike95490 · October 2019

Sounds like it's all propane related. ?

Estragon · October 2019

I'd be careful bypassing regulators, as the 500gal tank may be higher pressure. The primer seems like as safety thing, similar to a solenoid but done manually on the regulator instead of by powering a solenoid with a remote switch.

Dave Angelini · October 2019

Measure the pressure! I did not read the whole thing but without a measurement of good and bad you are in the dark.

icarus · October 2019

Second the notion of checking the pressure. Is the Garettson isn’t set up to deliver liquid rather than vapor? A small engine like an Eu 3000 certainly doesn’t need liquid delivery. Who did the conversion and do they supply any support? A lot of small engine LP conversions are sort of DIY stuff and specs are a bit hard to decipher.

I am having trouble wrapping my head around a LP “primer bulb”. Can you provide a spec/photo etc. I am also wondering if it is a safety solenoid shut off.

Tony

Graham Parkinson · October 2019

Inside either a big tank, or small tank - both are at the same pressure which is the vapour pressure of propane. Depending on temperature this may be around 60 psi to 120 psi. Usually there is a red regulator on big tanks (making 10-12 psi or 277 to 330 " of water) feeding a silver regulator on the house which makes 1/2 psi (7-12 " water).

Together the big tank and house regulator likely do the same thing as your 20 lb tank and Precimex which probably normally delivers 1/2 psi to the Garretson on your genset which is a vacuum controlled demand regulator connected to the carb venturi. The primer button on the Garretson is just to deliver propane initially to prime as there is not enough suction while hand cranking in the venturi to open the diagram valve in the Garretson until the engine is running. Sometimes the primer can be controlled by a solenoid for remote start setups or possibly electric cranking is fast enough/long enough to draw open the diagraphm, if the correct pressure is fed to the system.

Your plumbing from the big tank is likely downstream of the red regulator installed on the tank so you are possibly feeding your generator connector hose and Precimex regulator only 10-12 psi (277 to 330 " of water) whereas its probably designed for tank pressure.

Possibly what is happening is that you are double regulating with the Precimix installed and not getting enough pressure/flow to allow the generator to start without priming. The symptoms of running on a 20 lb bottle but not on a line to the 500 gallon tank suggest this. You should review your setup and report back before doing any modifications!

You can measure the inches of pressure appearing at the generator hose with a u trap full of water. The number of inches that your Garretson is calibrated for should be stamped on one of the circles on the left side. Google Garretson KN Manual, it will state what the threshold pressure is for the diaphragm to open. There is an adjustment screw that changes this but make sure you have the correct feed pressures!

56napco · October 2019

Graham Parkinson said:

Inside either a big tank, or small tank - both are at the same pressure which is the vapour pressure of propane. Depending on temperature this may be around 60 psi to 120 psi. Usually there is a red regulator on big tanks (making 10-12 psi or 277 to 330 " of water) feeding a silver regulator on the house which makes 1/2 psi (7-12 " water).

Together the big tank and house regulator likely do the same thing as your 20 lb tank and Precimex which probably normally delivers 1/2 psi to the Garretson on your genset which is a vacuum controlled demand regulator connected to the carb venturi. The primer button on the Garretson is just to deliver propane initially to prime as there is not enough suction while hand cranking in the venturi to open the diagram valve in the Garretson until the engine is running. Sometimes the primer can be controlled by a solenoid for remote start setups or possibly electric cranking is fast enough/long enough to draw open the diagraphm, if the correct pressure is fed to the system.

Your plumbing from the big tank is likely downstream of the red regulator installed on the tank so you are possibly feeding your generator connector hose and Precimex regulator only 10-12 psi (277 to 330 " of water) whereas its probably designed for tank pressure.

Possibly what is happening is that you are double regulating with the Precimix installed and not getting enough pressure/flow to allow the generator to start without priming. The symptoms of running on a 20 lb bottle but not on a line to the 500 gallon tank suggest this. You should review your setup and report back before doing any modifications!

You can measure the inches of pressure appearing at the generator hose with a u trap full of water. The number of inches that your Garretson is calibrated for should be stamped on one of the circles on the left side. Google Garretson KN Manual, it will state what the threshold pressure is for the diaphragm to open. There is an adjustment screw that changes this but make sure you have the correct feed pressures!

The regulator on the tank is red, the regulator on the house is brown. The fuel comes from the red tank regulator to the Precimix and not from the house regulator. The Honda is electric start and is controlled by the AGS controller for how long it cranks and how long between cranks it waits. Usually it cranks for 10/15 seconds and waits 2 minutes before trying again and tries cranking 4 times before faulting out. Before the Precimix is an Advanced Fuel Components electric solenoid. The Max inlet of the Garretson is 8 oz. (13.8" water column) (Garretson part # 039-122). I did find this You Tube video of the Garretson regulator, same part number too.

https://www.youtube.com/watch?v=CfM6D65MC_w  this explains the primer button as well. From what I've found, the Precimix is 100 psi inlet and 11" water column outlet. 11" of water column is ~6.35 oz per Sq inch. The guy that did the conversion is supposed to come back out but he is busy and in the meantime we're just trying to make sure its not something obvious as well as understand this system a bit better. A couple pictures are attached of the regulator setup.

56napco · October 2019

The Honda is electric start and controlled by the AGS. The AGS cranks the generator for 10 seconds and then waits 2 minutes between retries if it does not get a run signal that the generator has started. It will try 4 times before faulting out.
Attached are a couple pictures of the regulator setup- had to figure out how to post them here. The tank regulator is red which feeds the Precimix. The regulator on the house is brown- which is not part of this system as the generator is plumbed in before this regulator. What I've found about the Precimix is 100 psi inlet pressure and 11" water column outlet (6.35 oz per square inch). The Garretson is #039-122, max inlet of 8 oz. (13.8" water column) and uses vacuum to draw open the diaphragm. I did find this video that explains the Garretson regulator quite well and shows the primer button. https://www.youtube.com/watch?v=CfM6D65MC_w
The guy that did the conversion has been tough to get back out to look at this setup- he's an elderly guy and still very busy but is expected to come out again yet. Just wanted to make sure it wasn't something obvious or learn a bit more about this type of setup- as I stated in my first post I'm not that familiar with propane fuel systems. Will have to figure out how to measure the gas pressures and see what they are, this is at least a starting point.

shawnj72 · October 2019

You should have two Regulators One at the Tank From High Pressure 175-to and then from 10-12 psi To Inches of Water Low Pressure.. The One on your Tank Takes the 175 PSI in a 90 degree day and reduces it to 10-12psi. Then the one at the house converts 10-12psi to Inches of water about a half of a pound to around 10inches or so. You are going from high pressure then converting it from high pressure again then to the Garretson. I'm willing to bet if You removed the small Regulator Teed off from the brown one at the house to the Garretson it would work.. That s how mine is 5/8 line then 2ft of 1/2 all but the last two feet buried underground. Not knowing where you are from.. the colder it gets the less pressure it will deliver.. so in 0 temperature it will be less than 10 pounds delivered..I did put a remote shutoff also mine is a 13kw and works fine.. But we will see when we get those sub0 temps hope this helps.. Also I bet if you called your propane co they will be more than willing to answer questions or lend a hand.. Most will im willing to bet..

Dave Angelini · October 2019

Good Advice from shawn unless the tank is close to the house and may have a tank regulator that is a single unit regulator. I have seen quite a few of them both ways.

56napco · October 2019

shawnj72 said:

You should have two Regulators One at the Tank From High Pressure 175-to and then from 10-12 psi To Inches of Water Low Pressure.. The One on your Tank Takes the 175 PSI in a 90 degree day and reduces it to 10-12psi. Then the one at the house converts 10-12psi to Inches of water about a half of a pound to around 10inches or so. You are going from high pressure then converting it from high pressure again then to the Garretson. I'm willing to bet if You removed the small Regulator Teed off from the brown one at the house to the Garretson it would work.. That s how mine is 5/8 line then 2ft of 1/2 all but the last two feet buried underground. Not knowing where you are from.. the colder it gets the less pressure it will deliver.. so in 0 temperature it will be less than 10 pounds delivered..I did put a remote shutoff also mine is a 13kw and works fine.. But we will see when we get those sub0 temps hope this helps.. Also I bet if you called your propane co they will be more than willing to answer questions or lend a hand.. Most will im willing to bet..

We had tried removing the small Precimix and hooking up to the brown regulator and it did not help, it seemed to flood. Supposed to have the guy that did the conversion to come back out this weekend yet to make it right.

arby · October 2019

They have a regulator that pulls in the prime button with a solenoid. Had one hooked up to my Honda EX5500 that I converted to propane. I now have it disconnected since it starts fine without the prime. Make 100% sure that any vacuum in the carb is getting to that feed line from the regulator. That big regulator seems to require just a small amount of vacuum to open it.

PS: The problem I found with the electronic prime was that it pulled in too long causing flooding and then no start. Had it hooked up to the start switch. So on while starter cranked.

Also I was reading a while ago about needing a one thousand pound propane tank and an inch and a half hose for winter use. I noticed that one of my neighbours on the next lake over have that setup. I couldn't understand why except that a big long tank on its side would have more surface of propane.

I have two 100 pound tanks and a flop over valve and they seem to work fine.

56napco · November 2019

Back to square one- ordered a new conversion kit and waiting for that to show up. No support from the LP gas company or the guy that did the conversion in the first place. Will an auto primer be needed when using LP? Also, manometer is on order and waiting for that to be delivered as well. Will it have more issues starting the colder it gets? It can get down to -30F or less at times in the winter.

Saggys · November 2019

My old Onan 2.5LK propane powered generator requires a 120 gallon tank to operate at -20F according to the install manual. It is getting pretty tired but still starts most of the time in cold weather.

shawnj72 · November 2019

That is Unfortunate that you cannot get the installer to come back or get any help from your local Propane dealer. I still would look at the service line what size and how far. Then it shouldn't flood if brought in after the second regulator. But im not sure what kind of kit this is you have. I just know what has worked in the past. If you are coming in after the first regulator then this kit should be sized to exactly what the generator calls for to big or to small will definitely cause the problems you are having..If it floods when you start i would imagine a tad to big. You have the temperature extreme as i do and that will present a challenge also. As far as the prime a solenoid with a button at the start area so you can push and find how log it needs to start.. Stuff like this come easy for me but you kind of get what i am saying.. just a remote button and solenoid might be all you need if you do indeed need the prime.. Remember at -30 there wont be much delivery pressure so thats where sizing needs to be a bit bigger. I have 5/8 from mine and the tank is about 50ft away..

56napco · November 2019

The tank is about 30-feet away with 1/2" line from the tank to the generator regulator. The new conversion kit from US Carburetion should be here this week, using the snorkel system. The fuel is plumbed from the tank regulator to the generator (t-fitting before the house regulator). Been running on regular gas lately while waiting for the new LP kit to show up.

LP Generator Auto Start Issues

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