Generac Generator Inop

Ted

The pilot formerly known as Twin Engine Ted
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Our house has a 20kW Generac standby generator - propane powered. This was seemingly put in with the house so it's around 14 years old.

On Tuesday I came home to find the generator running, meaning the power was off. Sure enough, power was off. Go inside and find that nothing is working - including all the things that are normally covered by the generator. Great.

I did some checks. The auto start seems to be working (obviously) and I can hear the relay click over in the indoor panel that sounds like it's switching over to generator power once I shut off the house power. The generator itself has a 115V 15A GFCI breaker, and that outlet didn't have any power at it.

I opened up the generator and used my multimeter to measure voltage at the wires themselves for both the 110 and 220 with it running - 0V in both cases.

Generac seems to not want you to find out how to fix the things. I could find a parts list but I couldn't find much else, and even the parts list wasn't very good.

I'm wondering if anyone's dealt with this before and found any good resources for fixing the issue so I can avoid calling an expensive repairman to fix something that will take me 2 minutes and a $20 part.
 
In one commercial installation I’m aware of, they put the GFI outlets under the floor, and they were all tripped at some point (or never reset) before the generator kicked in.

Edit...I just read the part about 0V at the generator. In that case, I’d say it’s broke. ;)
 
Edit...I just read the part about 0V at the generator. In that case, I’d say it’s broke. ;)

Yeah, I've determined pretty conclusively that the generator isn't making power. Now whether that's the generating unit itself or the voltage regulator, that's another story.
 
Generac seems to not want you to find out how to fix the things.
Do you have the manual? I fixed a 15kw generac using the troubleshooting flowcharts in the manual and 2 youtube videos. But it was an auto start issue. The flow charts were detailed enough to isolate the issue enough to buy a single part. The videos confirmed the problem and how to change the part.
 
Do you have the manual? I fixed a 15kw generac using the troubleshooting flowcharts in the manual and 2 youtube videos. But it was an auto start issue. The flow charts were detailed enough to isolate the issue enough to buy a single part. The videos confirmed the problem and how to change the part.

My wife says she remembers seeing it but I've not found it. I'll check online.
 
Field windings have become demagnetized. Got an electric motor handy? Crank up the generator, plug in the motor and give it a spin by hand. The motor should "flash" or generate enough juice to excite the field and get you back in bidness.
You need to run the genny at least annually to keep it "excited".
Had this happen on a Lincoln ugly duckling welder/generator in the past.
 
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Field windings have become demagnetized. Got an electric motor handy? Crank up the generator, plug in the motor and give it a spin by hand. The motor should "flash" or generate enough juice to excite the field and get you back in bidness.
You need to run the genny at least annually to keep it "excited".
Had this happen on a Lincoln ugly duckling welder/generator in the past.

If it's an auto like Ted says, it should be starting once a week to do that anyway.
 
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It could be an automatic switchover but not an automatic maintainer. The weekly start-up is a newer than 15 years ago feature.

I have a 3kw generator and I start it every year on July 4th along with several other annual tasks just to keep it going.
 
It could be an automatic switchover but not an automatic maintainer. The weekly start-up is a newer than 15 years ago feature.

I have a 3kw generator and I start it every year on July 4th along with several other annual tasks just to keep it going.

Good point. I'm more used to commercial ones where maintaining has been an automatic feature for longer...
 
If it's an auto like Ted says, it should be starting once a week to do that anyway.

This one starts up once a week. Sunday at 9 AM "Oh good, the generator still works."
 
This one starts up once a week. Sunday at 9 AM "Oh good, the generator still works."

That _should_ be exciting the windings then. My boss has a Generac whole house generator and he's commented that in the time he's owned the house he's needed it maybe 5 times and it only worked once. :( I hope yours is much better than that.

John
 
That _should_ be exciting the windings then. My boss has a Generac whole house generator and he's commented that in the time he's owned the house he's needed it maybe 5 times and it only worked once. :( I hope yours is much better than that.

Yes. In almost 4 years of living here the system has worked perfectly each time the power goes out.

I also made sure when I wired up my subpanel for the garage that it would be powered by the generator. Because when the zombie apocalypse happens, I'll need my compressor and my welder to build the ZombieBanKillDozer.
 
Yes. In almost 4 years of living here the system has worked perfectly each time the power goes out.

I also made sure when I wired up my subpanel for the garage that it would be powered by the generator. Because when the zombie apocalypse happens, I'll need my compressor and my welder to build the ZombieBanKillDozer.

Prudent planning.
 
It'd be better planning if I was any good at welding.

I worked with a former machine maintainer years ago. I asked him if he could weld and he replied "I can usually hold things together until a welder gets here." Me too. Although after I tried welding with a DC welder, I think I could actually do that. It was so much easier than AC.
 
I worked with a former machine maintainer years ago. I asked him if he could weld and he replied "I can usually hold things together until a welder gets here." Me too. Although after I tried welding with a DC welder, I think I could actually do that. It was so much easier than AC.

My policy is that if my life depends on it, I don't weld it. The Zombie Apocalypse is another story of course since, well, zombies.

I have a junky flux core/MiG (I do flux core) welder from Harbor Freight. I actually surprised myself the other week when welding a 1/4" thick piece of steel on the brush hog that the weld looked halfway decent and held up after demolishing some brush.

Still, I don't trust my welding enough to weld anything that, if it failed, would kill me.
 
Need the model number and serial number, then go to the googles for a wiring diagram. I doubt it's anything major. Probably a relay some where. Usually wiring diagrams are inside the unit under a panel that is accessed by removing said panel. Would be surprised if there wasn't one for your generator unless someone pulled it and didn't put it back.
 
Have you been running that lean of peak? I hear how that can absolutely roon cylinders!
Seriously, good luck. Mine is still under warranty and I have a service guy who can fix it if needed. It starts up 8:30 every other Saturday for a self-test and started by itself last power failure, yay.
 

The one problem with that for me is that we have this nice 500 gallon propane tank that works great for fueling and if we went with a diesel we have to change that up.

But if you're thinking a real generator, here we go:

https://www.ebay.com/itm/Caterpilla...686211?hash=item4b532821c3:g:xFwAAOSwJ6Nb0i5y

That one makes me think:

30knnp.jpg
 
The one problem with that for me is that we have this nice 500 gallon propane tank that works great for fueling and if we went with a diesel we have to change that up.

But if you're thinking a real generator, here we go:

https://www.ebay.com/itm/Caterpilla...686211?hash=item4b532821c3:g:xFwAAOSwJ6Nb0i5y

I could get you one that runs off propane too, although maybe not that small. It was just the first link I grabbed.

I can't make out the first few digits on the S/N on that ebay listing or else I could tell you all sorts of stuff about that unit. I am guessing 1990's vintage. Our smaller gensets now put out 1000kw. The power density progression has been steady.

This is the smallest one we make here in Germany. You could sell power to your neighbors...

https://www.cat.com/en_US/products/...tion/gas-generator-sets/2841734473578834.html
 
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That _should_ be exciting the windings then. My boss has a Generac whole house generator and he's commented that in the time he's owned the house he's needed it maybe 5 times and it only worked once. :( I hope yours is much better than that.

John
My sister and her husband built a new house in Panama City, just across the bay from Tyndall AFB. They moved in on July 1. Hurricane Michael hit in early October. Their brand new Generac didn't work. And they couldn't get a repairman until after the power came back on, which was over a month.

I'm looking for a "real" generator. But my Lowes portable 5500Kw generator has worked find since 2004, except for 2016 when I tried to test start it, and it said no. I replaced the carb and it is working fine again. I really should change the gas once in a while.
 
I worked with a former machine maintainer years ago. I asked him if he could weld and he replied "I can usually hold things together until a welder gets here." Me too. Although after I tried welding with a DC welder, I think I could actually do that. It was so much easier than AC.

I can weld beautifully with acetylene, but horribly with arc. Go figger.

Rich
 
My sister and her husband built a new house in Panama City, just across the bay from Tyndall AFB. They moved in on July 1. Hurricane Michael hit in early October. Their brand new Generac didn't work. And they couldn't get a repairman until after the power came back on, which was over a month.

I'm looking for a "real" generator. But my Lowes portable 5500Kw generator has worked find since 2004, except for 2016 when I tried to test start it, and it said no. I replaced the carb and it is working fine again. I really should change the gas once in a while.

I drain the gas, drain the carb after I use mine. Change the oil too, plus a squirt of oil in the cylinder. Starts every time I need it. Just put the old gas in the car, generally it's not that old.
 
My sister and her husband built a new house in Panama City, just across the bay from Tyndall AFB. They moved in on July 1. Hurricane Michael hit in early October. Their brand new Generac didn't work. And they couldn't get a repairman until after the power came back on, which was over a month.

I'm looking for a "real" generator. But my Lowes portable 5500Kw generator has worked find since 2004, except for 2016 when I tried to test start it, and it said no. I replaced the carb and it is working fine again. I really should change the gas once in a while.

I have this one:

https://www.samsclub.com/sams/sua12000e-12000w-generator/prod20940007.ip?xid=plp_product_1_2

I start it and run it for a while during the first week of every month, then shut off the gas valve and let it run itself out of gas.

It can run anything in the house, just not all at the same time. In practical terms, I can't run the electric clothes dryer and more than one burner on the electric range at the same time, or do either of those things while running the air conditioner, without at least a change of tripping the breaker. I haven't come across any other combination that it can't handle.

I wired it into the main panel with a backfeed breaker and an interlock switch.

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It's not automatic, but it's easy enough to switch over, and I'm usually here to do it. And because I had so many rebate dollars accumulated from Sam's Club, the generator and everything needed for the installation only cost me about a grand out of pocket.

Of course, we haven't had a power failure since I bought it...

Rich
 
I'm looking for a "real" generator. But my Lowes portable 5500Kw generator has worked find since 2004, except for 2016 when I tried to test start it, and it said no. I replaced the carb and it is working fine again. I really should change the gas once in a while.

I was told to go with the water cooled Kohler's. They start at something like 36kW and cost silly money. I have a 5 ton geothermal heat pump as the biggest load I need to drive, so that'll take a silly generator to start with.
 
Whatever happened to roughing it when the power goes out? LOL

I live in an apartment with no backup. I have survived several power and internet outages. :)
 
Whatever happened to roughing it when the power goes out? LOL

I live in an apartment with no backup. I have survived several power and internet outages. :)

Summer time, not really a problem. Winter time, can be big problem.
 
I could get you one that runs off propane too, although maybe not that small. It was just the first link I grabbed.

I can't make out the first few digits on the S/N on that ebay listing or else I could tell you all sorts of stuff about that unit. I am guessing 1990's vintage. Our smaller gensets now put out 1000kw. The power density progression has been steady.

This is the smallest one we make here in Germany. You could sell power to your neighbors...

https://www.cat.com/en_US/products/...tion/gas-generator-sets/2841734473578834.html

I like it!

Yeah, the power density has gotten a lot better. Engines more efficient etc.

Hopefully I can get this thing working. I figure this weekend I’ll do some more tests, hopefully figure out the problem and order the replacement part. If not I’ll think more about what to do.
 
Summer time, not really a problem. Winter time, can be big problem.

That is actually one of the problems with this generator. The house is all electric HVAC but the generator isn’t big enough to power the HVAC, or if it can it’d be really straining. Max output is around 86 amps.

I’d need a 60 kW or so generator to really cover the whole house uninterrupted.
 
I’d need a 60 kW or so generator to really cover the whole house uninterrupted.

Exactly. My cousin, a Kohler dealer, is my generator dude. For me, he got a floor model 17kw that gives my 5K sqft house 'just enough' electricity: sump pumps, water pump, heat via a boiler in the winter, kitchen (less oven), selected circuits to have lights and comfort items (tv and internet) most places. No a/c, but if needed we have a window unit to mount in the MBR for extended outages in the warm seasons.

The houses with octogenarians get the 60kw whole house models. Set it and forget it.

We all have 1k gal. propane tanks. I figure mine will power the house and the flamethrowers for a couple weeks during the zombie apocalypse.
 
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For work I found a 2008 325KW natural gas generator with just over 500 hours on it. ~$80k 3 years ago. We got the gas line installed literally the day before hurricane Irma went through. We were the only business running in the industrial park that week. Paid for itself & installation the first week. Used can be quite the value.
 
Whatever happened to roughing it when the power goes out? LOL

I live in an apartment with no backup. I have survived several power and internet outages. :)
I could probably do that too, if I lived in Ohio. But down here in Florida, us old people start dying when the heat AND the humidity hang around 90+, even at night. One night I tried sleeping out on the porch. I thought I was going to need a blood transfusion from all the bug bites.
 
Summer time, not really a problem. Winter time, can be big problem.
Winter would be a piece of cake. I might need an extra sheet at night, and perhaps wear a t-shirt to bed. But summer without power can cause death.
 
I have this one:

https://www.samsclub.com/sams/sua12000e-12000w-generator/prod20940007.ip?xid=plp_product_1_2

I start it and run it for a while during the first week of every month, then shut off the gas valve and let it run itself out of gas.

It can run anything in the house, just not all at the same time. In practical terms, I can't run the electric clothes dryer and more than one burner on the electric range at the same time, or do either of those things while running the air conditioner, without at least a change of tripping the breaker. I haven't come across any other combination that it can't handle.

I wired it into the main panel with a backfeed breaker and an interlock switch.


It's not automatic, but it's easy enough to switch over, and I'm usually here to do it. And because I had so many rebate dollars accumulated from Sam's Club, the generator and everything needed for the installation only cost me about a grand out of pocket.

Of course, we haven't had a power failure since I bought it...

Rich

I have a similar set up 7500 watts/8500 peak. I start mine every couple of months and throw the shop vac and the hair dryer on to make sure it can handle an electrical load.
I got mine after the 2007 ice storm after spending 3 days with no electricity or heat. Didn't need it for about 5 years and I think I've used it half a dozen times total.
 
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