Natural Gas Generators

[abita_brewing]

Just finished the site survey and signed everything. total cost $22.5K for a 27kw liquid cooled Generac, an extra 85ft of electrical above the 20ft they "give you". All permits, and a gas meter upgrade

They will be pouring a 6 inch thick concrete pad, and the generator will be bolted to it. Pretty excited! 18 to 25 week lead time though

I got 14kw kohler installed for ~$7k. That was genset, transfer switch, electrical wiring, plumbing, and pad.

Re: generator pad. I used an elevated pad filled w/ rocks to absorb vibrations. It's through the bedroom wall, 4 feet from my head, and I can barely hear it.

 

[biggen]

Damn that’s a pretty good deal. Did you contract out yourself?

Generac 24kw is costing me $12k for everything. Plumber is coming out today to finish plumbing it up. I had my house gas pressure increased from 1/4 psi (7” W.C.) to 2 psi so I had to also put appliances regulators on my gas grill, stove, and hot water heater. At least now the Gen won’t be starved for fuel with a 2psi system. Also gives me headroom to move to a tankless water heater later this year.

 

[IReallyLikePizza2]

That's marketing.

Not around here, if a house has a Generator, odds are its a Generac

I'm sure its BECAUSE of their marketing, but my original point still stands that there is more of them out there than anything else

 

[IReallyLikePizza2]

Damn that’s a pretty good deal. Did you contract out yourself?

Generac 24kw is costing me $12k for everything. Plumber is coming out today to finish plumbing it up. I had my house gas pressure increased from 1/4 psi (7” W.C.) to 2 psi so I had to also put appliances regulators on my gas grill, stove, and hot water heater. At least now the Gen won’t be starved for fuel with a 2psi system. Also gives me headroom to move to a tankless water heater later this year.

Got any pictures of the install so far?

 

[RevB]

Has anyone gotten one installed? What do you have, and how much did it cost?

In the order of preference I think Kohler is the best, Cummins is second, and Generac is third. However, the Generac units are popular enough I think it may be easier to find parts

Liquid cooled is preferable to air cooled, but almost doubles the cost. Sadly my local Kohler reseller is kind of annoying, so I'm looking at the Cummins units. around $10K for a 22kw air cooled, or $17K for a 22kw Liquid Cooled.

Still trying to decide between liquid or air. I think Liquid would be nice, but is it 7K more valuable than the air cooled? Probably not. They both do the job, and I'm not losing power every week

Air works fine just keep the filters and enclosure clean. The only problem I had was, since this was an inherited unit with which I had no history, the first time it fired up under load it would start to surge....ignition, fuel or air. Turned out to be the air filter was sourced out of the Philippines and was speced to have a flame retardants applied. It was applied all right, right up to the point the engine couldn't breath. Replaced with a Wix and all was well. Found out the HQ for Generac stuck their dealers with a lot of dicked up filters that they wouldn't reimburse them for so they just got chucked. That right there might tell you a little about Generac tho I haven't had a problem with the unit, but I do all my own work, so.....

 

[abita_brewing]

Damn that’s a pretty good deal. Did you contract out yourself?

Generac 24kw is costing me $12k for everything. Plumber is coming out today to finish plumbing it up. I had my house gas pressure increased from 1/4 psi (7” W.C.) to 2 psi so I had to also put appliances regulators on my gas grill, stove, and hot water heater. At least now the Gen won’t be starved for fuel with a 2psi system. Also gives me headroom to move to a tankless water heater later this year.

Yes, and I built the pad.

$36 low pressure gauge to make sure unit not starved for pressure
$141 4x4 treated and screws
$45 gravel
$861 plumber
$1908 electrician
$3822 genset w/ xfer switch
$131 battery
$6945 subtotal
Paid for most of the unit w/ home depot gift cards... amex points.

Plumber tapped into gas line, added a 't' for gauge, and ran to unit.

Electrician installed xfer switch, new load box, moved ALL circuits over, did initial crank/run cycle, and submitted warranty paperwork. He was kohler certified so I got 2x warranty if he did initial cranking.

Re: 14kw unit. This thing fires off my 4 ton a/c w/o breaking a sweat. It easily runs the a/c, stoves, cooktop eyes, dryers, 120v appliances, etc. Only real limitation is that you can't go "crazy"... the dryers are 7200watts each.... so if you have clothes drying I can only use one unit at a time.

Anything much over 14kw would require gas pressure upgrade, which I did NOT have to do.

Longest outage so far was 30 hours in summer of 2021.

As far as air versus water... I'd go air every time. Less cost, complexity, maintenance, etc. Generator engines, unless you have a block AND coolant heater are subjected to a ROUGH life. They are cranked and put under full load within 3-5 seconds typically. They are NOT going to last for 5-10k hours. And unless your power is HORRIBLE, you won't need it to. This unit is just under 8 years old and has 197 hours on it.

 

[abita_brewing]

Worth noting... my unit goes from 'full' on dipstick to 'low' after about 36 hours of loaded runtime.
Maybe my rings are not sealing due to full synthetic during break in. Maybe this is typical for air cooled engine (higher oil temps). I don't see leaks. I don't smell oil. Shrug...

 

[RevB]

My power was out for eight days and my liquid cool natural gas 20kw Winco generator did not break a sweat in 90-degree weather. I do not think an air-cooled generator would have survived. Air cooled engines are not made to run continuously. I purchased this generator off of Ebay with less than 300 hours with the transfer switch a few years ago for $1100 plus shipping. My generator has a Ford four-cylinder motor in it. I installed it myself

That's odd.....all my aircraft engines are air cooled. Guess I'll have to break the news to them that they should quit.

 

[abita_brewing]

And FWIW, my electrician was certified by generac and kohler. However, he endorsed kohler due to generac not working with 3rd party xfer switches/etc.

Personally, I went with kohler due to a then-current class action lawsuit against generac regard delaminating stator assemblies. And having owned a portable generac in the past... not being very impressed w/ engine construction and overall design.

I see a TON of generac advertising. I tend to go with the company with less advertising... my guess is that they have more $ to invest in the equipment if they are not spending it all on ads.

 

[IReallyLikePizza2]

Worth noting... my unit goes from 'full' on dipstick to 'low' after about 36 hours of loaded runtime.
Maybe my rings are not sealing due to full synthetic during break in. Maybe this is typical for air cooled engine (higher oil temps). I don't see leaks. I don't smell oil. Shrug...

This is standard on the 3600RPM air cooled units, they ALL burn oil, and honestly is a deal breaker for me. This means you can't run it for longer than a few days without shutting it off to top it back up. My 1800RPM liquid cooled NEVER deviates from full, it doesn't burn any measurable quantity of oil

They just run too fast and too hot for me, especially here in Texas where its only getting hotter

The air cooled are also derated at high temps, much more so than the liquid cooled. The added maintenance of flushing the coolant isn't too bad, it takes less than 20 mins to do. Another thing to note is that on Generac Air cooled generators (Not Kohler because they use hydraulic lifters) you need to do valve adjustments, which you do not on the liquid cooled

So the maintenance argument is a wash, at least if you stay in Generac land

No doubt Kohler makes a better general all around

 

[IReallyLikePizza2]

That's odd.....all my aircraft engines are air cooled. Guess I'll have to break the news to them that they should quit.

Lets face it, an aircraft engine is not built to the same tolerances as a budget standby generator that costs no more than $4000

 

[IReallyLikePizza2]

Also worth noting that most of the air cooled gensets hold just under 2 quarts of oil max, that oil is running HOT and getting used up.

Meanwhile, the liquid cooled units hold just over 5 quarts, and run MUCH cooler. Seems like a better idea all around

 

[RevB]

This is standard on the 3600RPM air cooled units, they ALL burn oil, and honestly is a deal breaker for me. This means you can't run it for longer than a few days without shutting it off to top it back up. My 1800RPM liquid cooled NEVER deviates from full, it doesn't burn any measurable quantity of oil

They just run too fast and too hot for me, especially here in Texas where its only getting hotter

The air cooled are also derated at high temps, much more so than the liquid cooled. The added maintenance of flushing the coolant isn't too bad, it takes less than 20 mins to do. Another thing to note is that on Generac Air cooled generators (Not Kohler because they use hydraulic lifters) you need to do valve adjustments, which you do not on the liquid cooled

So the maintenance argument is a wash, at least if you stay in Generac land

No doubt Kohler makes a better general all around

Funny how mine doesn't "burn oil".....guess the nameplate is wrong.

 

[RevB]

Lets face it, an aircraft engine is not built to the same tolerances as a budget standby generator that costs no more than $4000

Wanna bet? You're bamboozled by an application.....for a Continental 40psi is fine as a lower limit for differential compression check. Lycoming thinks a quart of oil burned in an hour is normal. Damn right.....in a lot of cases they're built way worse and they still charge you quadruple the price the engine should be.

 

[IReallyLikePizza2]

If you have a 3600RPM air cooled genset that doesn't burn oil, hold on to it, because its the only one on the planet.

 

[IReallyLikePizza2]

Crimped MC4 connectors on my cheap 100w foldable Harbor Freight solar panel. Much easier now, no big mess of adapters from SAE. This little Ecoflow on sale at $269 is one of my favorite purchases

 

[abita_brewing]

Also worth noting that most of the air cooled gensets hold just under 2 quarts of oil max, that oil is running HOT and getting used up.

Meanwhile, the liquid cooled units hold just over 5 quarts, and run MUCH cooler. Seems like a better idea all around

That's not apples to apples though. Take an engine which exists in both air and liquid versions. Oil capacity will be the same typically.

I used to mow commercially as a side gig... my mower has a 35 briggs/diahatsu on it. Does not burn a drop and I push it HARD as I only cut acreage... no lawns. My smallest job is 3 acres... largest is 25. You can get the same engine in water cooled... will have same oil capacity.

There's also an option that my engine is not broken in yet. It's only got 200 hours, and only 75 of those are loaded. I really should have used non synthetic on the initial 10 hour change... time will tell.

And again... unless someone lives in an area with absolutely horrible power... none of this will matter. I am 8 years in with 200 hours.

If everyone wants to split hairs... then there's the time value of your money. I'm pulling ~15% CAGR on my investments... so I want to keep gen costs down and keep the extra $ invested. If/By the time the engine starts to fail... I'll replace the whole unit and get new everything, transfer switch included.

Generators are just hard on engines though. The local hospital's dual industrial units BOTH grenaded their engines ~2 weeks ago in a short power outage. Left the hospital w/ only UPS/battery power. It was BAD.

 

[IReallyLikePizza2]

off topic, but you guys see this? $179 with the coupon applied...

Amazon.com

 

[RevB]

If you have a 3600RPM air cooled genset that doesn't burn oil, hold on to it, because its the only one on the planet.

To be honest, never said it doesn't burn oil. As a matter of record, any engine that doesn't burn oil is by far the exception and for reasons of lubrication is to be avoided. Rings need modest lubrication...the cylinder/ring interface does not last long without lubrication. The matter up for debate is how much oil per unit time becomes unacceptable. If I can run for 96 hours and have a total use of 10ml that becomes 2.5 ml per day. The limiting factor for any modern air cooled engine of aluminum construction will be the barrel temperature at the base of the fins just short of the head/cylinder interface in which the rings would normally run. Ensuring that the temperature never gets more than 250F to 260F or so for conventional oils or 20F higher than that for synthetics. Oils need to be above 220F to volatilize water in the oil and to have the additive package neutralize acidic reactions of the residual sulfur and other fractional elements of conventional oils. Cooling airflow is therefore targeted to keep these oil temps between 220 and 280F. "Heavy" loads that do not significantly drop the RPMs such as zero turn hydraulic or constant speed applications such as carbureted generators or aircraft IC engines will operate just fine in ambient elevated temperatures less than 100 degrees or so. Fuel injected aircraft can manage temperatures by running rich of peak using fuel to cool or lean of peak using air to cool....something any carbureted engine will not be able to take advantage of. Aircraft have the added advantage of adiabatic lapse rate cooling as altitudes increase.

Went way to far with this.....

 

[RevB]

That's not apples to apples though. Take an engine which exists in both air and liquid versions. Oil capacity will be the same typically.

I used to mow commercially as a side gig... my mower has a 35 briggs/diahatsu on it. Does not burn a drop and I push it HARD as I only cut acreage... no lawns. My smallest job is 3 acres... largest is 25. You can get the same engine in water cooled... will have same oil capacity.

There's also an option that my engine is not broken in yet. It's only got 200 hours, and only 75 of those are loaded. I really should have used non synthetic on the initial 10 hour change... time will tell.

And again... unless someone lives in an area with absolutely horrible power... none of this will matter. I am 8 years in with 200 hours.

If everyone wants to split hairs... then there's the time value of your money. I'm pulling ~15% CAGR on my investments... so I want to keep gen costs down and keep the extra $ invested. If/By the time the engine starts to fail... I'll replace the whole unit and get new everything, transfer switch included.

Generators are just hard on engines though. The local hospital's dual industrial units BOTH grenaded their engines ~2 weeks ago in a short power outage. Left the hospital w/ only UPS/battery power. It was BAD.

"I really should have used non synthetic on the initial 10 hour change... time will tell.". Break in is always done with non-detergent oil and loaded right from the start. No babying allowed. Used to rebuild VW engines and was fortunate enough to live on top of a hill in PA. Straight weight 30 and run it just enough to get to the road and coast down to the bottom engine off. Fire it up and back up the hill in third gear wide open. The rings would be well seated after two runs. Same for aircraft with variable pitch props and injection...right after take off you increase the pitch so the engine is loaded, watch the cylinder head temps and manage the EGT. Don't run way rich as combustion by product will glaze the cylinders...run it just past peak egt on the last cylinder to peak (they don't do it all together generally) and always wide open for peak cylinder pressures. These are big jugs and will take a bit to seat. You can tell when each cylinder has seated by watching the head temps as they will suddenly drop 30 to 40 degrees.....if you can call 5 minutes sudden. These temps aren't instantaneous.