Generac 15kw 2 wire auto start help

[Affordable DC Generators]

Out fixing these toilets every day. Secretly I deliver Affordable DC Generators that are up by the passenger seat. Don't tell anyone!

 

[rfbuehler]

It’s not that difficult. It takes a couple of relays. One relay takes the NO contact from the inverter and opens a 240 line from the inverter out. These two lines go to the Generac. On loss of 240 the generator starts running. When power is stable it provides a 12v signal back. I use that to close a contractor, that way you do not supply the inverter until you have stable power. There is another pair you will need. You need to supply the GenSet with 120v for the battery charger. With these three things you can get rid of the transfer switch. I also add a indicator when the contractors close. (I am using 2 SS relays for the contractor, one for L1 and one for L2)

 

[DEEP WOODS WARNERS]

It’s not that difficult. It takes a couple of relays. One relay takes the NO contact from the inverter and opens a 240 line from the inverter out. These two lines go to the Generac. On loss of 240 the generator starts running. When power is stable it provides a 12v signal back. I use that to close a contractor, that way you do not supply the inverter until you have stable power. There is another pair you will need. You need to supply the GenSet with 120v for the battery charger. With these three things you can get rid of the transfer switch. I also add a indicator when the contractors close. (I am using 2 SS relays for the contractor, one for L1 and one for L2)

Can you send me detailed information?

 

[beastman]

I too have an older generac and will have this same sort of issue.. mine is the box style from 2007 era with the 100a transfer switch. I think trying to replicate the manual switch is the best path to get this to work as you could just use a relay to close the contact between the two points and it should startup within 10-20 seconds. I have considered upgrading to a newer generac from my current 16kw but at $5k for something that is rarely used i'll try to make this one work.

 

[beastman]

It’s not that difficult. It takes a couple of relays. One relay takes the NO contact from the inverter and opens a 240 line from the inverter out. These two lines go to the Generac. On loss of 240 the generator starts running. When power is stable it provides a 12v signal back. I use that to close a contractor, that way you do not supply the inverter until you have stable power. There is another pair you will need. You need to supply the GenSet with 120v for the battery charger. With these three things you can get rid of the transfer switch. I also add a indicator when the contractors close. (I am using 2 SS relays for the contractor, one for L1 and one for L2)

Great post. That all makes sense. Any suggestion on the brand of relays for the 240v line?

On the 120v line to charge the battery, do you have any suggestions? I would think we might be able to get away with a simple battery charger (trickle) hooked to 120v instead of using the control board off of the inverter.

 

[Affordable DC Generators]

If you have a Generac that doesn't have two wire start capability then it's pretty old. I have a yard full of these square bodies. You are wasting your time trying to make it work. They are not reliable at this point and you'd be better off spending your time making a better game plan then investing in a 15-20 year old square body Generac.

 

[beastman]

If you have a Generac that doesn't have two wire start capability then it's pretty old. I have a yard full of these square bodies. You are wasting your time trying to make it work. They are not reliable at this point and you'd be better off spending your time making a better game plan then investing in a 15-20 year old square body Generac.

I did replace the gas valve a few years ago ($200) and it will start up with ether. I think it probably needs a valve lash adjustment and maybe a new intake gasket. The alternative is spending another $5k on something that is rarely used which could be put towards buying more LiPo4 batteries from signature solar to build up the bank.

 

[Affordable DC Generators]

I did replace the gas valve a few years ago ($200) and it will start up with ether. I think it probably needs a valve lash adjustment and maybe a new intake gasket. The alternative is spending another $5k on something that is rarely used which could be put towards buying more LiPo4 batteries from signature solar to build up the bank.

I would have to see a picture of the unit or a model number but valve lash will definitely cause a hard start.

The choke assembly in the air cleaner will not engage so that will cause a rough start.

A lot of those mixers will also have the throttle plates loosen up and go basically wide open because the screws vibrate out.

I would also not use ether to try to start it as they really like the backfire and melt the plastic air box. I would figure out why you have a fuel issue first.

If you are fixing this yourself this is one thing, but if you are paying a pro to come out you are going to reach a point where it is cost prohibitive to fix this.

If you don't need a generator that much I would suggest just go by a quality portable like a Honda for a WinCo and just manually run it when you need generator power. Trying to save an automatic standby that is 15 years old is going to get expensive very fast and probably not worth it.

 

[beastman]

I would have to see a picture of the unit or a model number but valve lash will definitely cause a hard start.

The choke assembly in the air cleaner will not engage so that will cause a rough start.

A lot of those mixers will also have the throttle plates loosen up and go basically wide open because the screws vibrate out.

I would also not use ether to try to start it as they really like the backfire and melt the plastic air box. I would figure out why you have a fuel issue first.

If you are fixing this yourself this is one thing, but if you are paying a pro to come out you are going to reach a point where it is cost prohibitive to fix this.

If you don't need a generator that much I would suggest just go by a quality portable like a Honda for a WinCo and just manually run it when you need generator power. Trying to save an automatic standby that is 15 years old is going to get expensive very fast and probably not worth it.

I am pretty sure it needs the valves adjusted. I should clarify that it will start with 'ether' is actually a non-ether based carb cleaner as recommended by one of the local generac technicians in my area to get the unit up and running after sitting for some time. So my unit will start for a few days after getting it going but then it's hard to start. One tech thought the intake gasket might be bad and the unit has to somewhat re-prime itself before starting again.

The choke does work during startup, it closes back and forth during crankup.

So I believe it's most likely going to need an intake gasket, etc. The gas valve is brand new and has less than a few hours on it. The unit was purchased in 2009 second-hand from a generator company and was used off grid for our house before the power was brought in to run the well pump and some other miscellaenous items during construction. It sat for a few years in between and was not wired up to the 100a transfer switch. I bet the generator has less than 10 hours in the last 12 years but the oil has been changed a few years ago to a full synthetic. I keep the battery out of the unit and on a separate maintainer because these units seem to kill batteries every 3-4 years from what the generac tech has said. I am willing to do the work on it and I don't hire techs for about anything, so I think for the cost of a valve adjustment and some new gaskets it might function as expected. The plugs were replaced in 2020 too. My primary reason for a generator this size is to run my 5HP 240v single phase well pump when the power is out. Looking at costco today I saw a honeywell 22kw w/ 200a transfer switch for $5400 before tax, so the final bill before installation would be $6k. I am willing to dump $500 into this one to get it reliable again for 3-4 years.

I have a EU3000i honda that is primarily used as a worst case scenario to keep the fridges and freezers going for extended outages, but it's only 120v and I run 100' extension cords all over the place to make this work.

 

[Affordable DC Generators]

You can buy a 240v 5000 watt portable for way under $1000. I'd go that route and keep a spare carb for it.

On your unit it sounds like it is losing prime in the regulator. If the sheet metal plenum has a leak it's going to bleed down and cause a first initial long crank for it to fill back up.

I wouldn't waste time doing anything until you know the valves are adjusted. Gaseous fuel system requires good compression to get a good vacuum to pull fuel in. I use my finger or the handle of a screwdriver to prime the system. When you block the throttle it immediately pulls a ton of fuel through the demand regulator.

I would highly advise against any starting fluid. If it backfires you are going to explode the airbox. I never have but customers have and I replaced them. Mostly 8kw units but it's all plastic. A metal carb is more resilient.

Either way I have a trailer full of square bodies. I get you are trying to salvage it and save money. There are a lot still working fine in the field. But I have a trailer full of them going to scrap.

Just put a battery maintainer on it directly on the posts and keep it plugged in all the time. The battery charge circuit in the square body sucks brand new and is overly complicated and expensive to fix. I fix them with factory parts when they are a home standby but if you are using it as a portable or emergency use only I'd just keep a trickle on it and call it good.

 

[beastman]

5000 watts won't start my 5HP 240v well pump, it requires a minimum of 14-15kw to do so. That's why the 16kw generac is so critical.

If you mean the regulator, are you talking about the regulator from the propane tank or the regulator that sits behind the battery? That gas inlet valve/regulator was replaced in 2019 and does not have even 2 hours on it. It was brand new and was a few hundred bucks. That is what was recommended by a small engine mechanic friend of mine who works on these occasionally as the material inside those regulators breaks down over time.

I'll get the valve lash adjusted before I do anything further on messing with the fuel system.

The fluid being used is a non-ether based carb cleaner to startup the engine as recommended by a local generac tech from back in 2012 to me as how to get the system primed and supposedly they do this all the time for customer testing. No backfires.

I'll do the cheap 12v maintainer on it once I get this going as the transfer switch I believe is the only connection which sends 120v to charge the battery. That is a good suggestion. Maybe even just put it on a small 12v solar panel as a maintainer.

I appreciate the feedback, I think it's worth saving due to the low hours and parts already invested. It runs perfectly fine once going, just cant get enough vacuum to start through the regulator or similar at this point to auto-crank. I'd rather buy another 30kw of batteries or more inverters than invest more than a few grand in a generator.

BTW, do you happen to have any replacement airboxes you want to sell? I am wondering if this isn't part of the problem.

Generac Genuine Part 0G8296 ASSY,NG/LP MIXER H990 14/17KW​

- Brock

 

[Affordable DC Generators]

Bummer, that's a big load for anything to handle. I get it.

Your symptom sounds exactly like valve adjustment or a weak engine like low compression. A lot of these older units don't have an hour meter so I see a lot of calls for diag. I show up and it's the same story. Hasn't been serviced in years, blah blah blah. Cranks non stop. I jam my thumb down the hole of the throttle body and it fired right up and runs like new.

I think if they fault out for whatever reason, they sit for weeks, lose prime, then can't get restarted within the 3 crank cycles.

The other issue with this unit is that the engine, electronics, and fuel system are still being made. The back end is discontinued so just be aware of that. I don't have that parts, I only stock the AVR, battery charger, and other small parts for the old square body.

 

[justgary]

But I have a trailer full of them going to scrap.

I'm not sure where you are, but I have always wanted to grab a 10kW-15kW back end that I can gear up from a tractor PTO. I have a 10kW square body that a friend gave me, but it still runs fine and I don't want to rip it apart.

 

[Affordable DC Generators]

I'm not sure where you are, but I have always wanted to grab a 10kW-15kW back end that I can gear up from a tractor PTO. I have a 10kW square body that a friend gave me, but it still runs fine and I don't want to rip it apart.

The store I work for is in Stratham NH. I have a whole trailer full of squares that are going to scrap. I know I have a 10kw back end in a box on the shelf. Used unit, brushless, would need a cap to work and also the engine plate.

I don't use them on projects because they are discontinued. I wouldn't build a system around a part that is no longer available. But most generator shops will have tons of these in a bone yard.

Most of these systems are standard bolt patterns so you could always mix and match the engine and alternator.

I just picked up an old Lombardini air cooled diesel generator from a fire truck. Back end seemed to have a random dead short. So I bought an alternator off a Generac XD5000 diesel portable which happens to be made by Mecc Alte. Generac uses them so I got it right from them brand new. It's all built like Legos.

So you could always just buy a gas V twin engine like a Honda or cheaper knockoff and put your back end on it. The voltage reg doesn't care. Then you have your backend with the power you need with a new gas engine.

 

[beastman]

Bummer, that's a big load for anything to handle. I get it.

Your symptom sounds exactly like valve adjustment or a weak engine like low compression. A lot of these older units don't have an hour meter so I see a lot of calls for diag. I show up and it's the same story. Hasn't been serviced in years, blah blah blah. Cranks non stop. I jam my thumb down the hole of the throttle body and it fired right up and runs like new.

I think if they fault out for whatever reason, they sit for weeks, lose prime, then can't get restarted within the 3 crank cycles.

The other issue with this unit is that the engine, electronics, and fuel system are still being made. The back end is discontinued so just be aware of that. I don't have that parts, I only stock the AVR, battery charger, and other small parts for the old square body.

Update on 16kw- I spent some time and did a valve lash adjustment. The cylinder closest to the enclosure had .003 valve lash at TDC. The cylinder closest to the removable panel had some issues. One valve was about .001 and the other one was probably around .007-.008. I re-adjusted both to .003. After adjustment the generator still isn't getting any gas. I inspected the two hoses connecting to the replaced gas regulator - OUT 1 goes to the NG hose and OUT 2 goes to LP. The bottom of the hose was starting to split a bit where it connects to the barb. I cut both hoses about 1" shorter and now they are snug w/ the clamp. Generator cranks but will still not start. Gas company came out to refill my propane tank this weekend and they validated the tank connected to the generator has 13.5wc. The unit is not getting gas during cranking. Another forum had someone w/ the same model (e.g. 0052541 model, serial 4927167, 16000 watts) and said the plunger and regulator coil is likely the problem. Ordering a new gasket, plunger and regulator coil. 12v is getting to the coil during crankup so this is most likely the key issue preventing this thing from operating normally. Another $53.00 to zillerelectic.com and hopefully ill figure out this week if that is the end of these problems.

 

[Affordable DC Generators]

I think LP should be 10-12" off the top of my head.

I wouldn't worry about any of that hose stuff. The solenoid is troublesome especially if it's the shorter version.

A quick test is to tap it while cranking, if it immediately it's the solenoid. I'd replace it with the taller version anyway. You have to get the matching plunger as well. Probability is high for that part failing compared to everything else.

 

[Supervstech]

I think LP should be 10-12" off the top of my head.

I wouldn't worry about any of that hose stuff. The solenoid is troublesome especially if it's the shorter version.

A quick test is to tap it while cranking, if it immediately it's the solenoid. I'd replace it with the taller version anyway. You have to get the matching plunger as well. Probability is high for that part failing compared to everything else.

10 to 12 at the burners/post regulator.
But should be 12 to 14" feeding the control.

 

[Affordable DC Generators]

10 to 12 at the burners/post regulator.
But should be 12 to 14" feeding the control.

I can't tell you off the top of my head for that old of a unit but most would not be that high. The liquid cooled units go up to 14".

So I would advocate to check the placard or owners manual for the spec.

The other issue I have with that is there shouldn't be more then a 1" drop from static to running. So you would not see a spec that varies that much going into the reg and the other test port after the fuel solenoid.

 

[Supervstech]

I can't tell you off the top of my head for that old of a unit but most would not be that high. The liquid cooled units go up to 14".

So I would advocate to check the placard or owners manual for the spec.

The other issue I have with that is there shouldn't be more then a 1" drop from static to running. So you would not see a spec that varies that much going into the reg and the other test port after the fuel solenoid.

Spec is to show what a regulator can control.

Burner pressure needs to be constant 10” post regulator. The regulator can handle 14” and output constant 10” some regulators are set to 2PSI and output constant 14” to the equipment regulator.

 

[Affordable DC Generators]

Spec is to show what a regulator can control.

Burner pressure needs to be constant 10” post regulator. The regulator can handle 14” and output constant 10” some regulators are set to 2PSI and output constant 14” to the equipment regulator.

Not sure what you are referring to. The generator has a demand regulator inside which typically has a window of 10-12" of operating pressure for LP. Nothing else is allowed.

I think you are referring to the primary and secondary pressure regs outside of the unit. There is no "burner" inside of a generator. A demand regulator does not regulate pressure. If establishes the mixture going to the engine.