# Old Generac transferswitch



## calimurray (Apr 29, 2007)

Recently we replaced an old 7kw generac generator with the new 8kw Siemens generator, and it was wired through an old generac transfer switch.

When we test the new generator by turning off the power, the generator kicks on but the transfer switch does not, I checked the fuses and there was two bad fuses, which are really hard to find. The fuses are on order as of now. Any ideas why the transfer switch is not compatible with the new generator.

One thing I noticed also was the terminals in the transfer switch are different then the new generator, I have 2 utility feeds, two loads, 28, 194 terminals.

In the generator I have n1,n2, 28, and 0 -


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## MDShunk (Jan 7, 2007)

There shouldn't really be any such thing as "not compatible" with the new generator. Set of contacts closes to start the generator. That's about it. When transfer switch sees good power from the genset for a period of time, it transfers. Simple as that. One of two things would be my guess... you wired something wrong or the transfer does not like the profile of the power from the generator.


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## calimurray (Apr 29, 2007)

> or the transfer does not like the profile of the power from the generator.


What do you mean by profile of power?


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## MDShunk (Jan 7, 2007)

calimurray said:


> What do you mean by profile of power?


Voltage and frequency, mainly.


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## wirenut1110 (Feb 12, 2008)

The transfer switch needs to see 12 vdc on terminals 194 & 23 to work. If your terminals 28 & 0 are a different voltage, then you'll need to make that change with another relay or something. Polarity is important also.

The generator uses N1 and/or N2 to sense utility voltage (this is where the fuses come in to protect that circuit where it goes to the generator)

When there's a loss or reduction in power the generator will start, after brief warm up, the generator control board sends 12 vdc on terminals 194 & 23 to the transfer relay(located inside transfer switch) which initiates a transfer if there's voltage from the generator.
Here's a wiring diagram for the transfer switch and "old" generator. Starts on page 29.
http://www.guardiangenerators.com/Documents/ViewPDF.aspx?ItemNbr=0F9421&dtMO=08/16/2006&typ=m


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## MDShunk (Jan 7, 2007)

wirenut1110 said:


> The transfer switch needs to see 12 vdc on terminals 194 & 23 to work. ]


That's dumb. So, those old Genercrap transfer switches will transfer when you have awesome 12vdc, but the 120/240 could be crap and they'll still transfer? No wonder I don't like Generac.


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## wirenut1110 (Feb 12, 2008)

I was just shooting out the simple version, I'm sure it may be a little more complicated than that.


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## calimurray (Apr 29, 2007)

Thanks for the link wirenut1110 I have been trying to find the schematics for the older system and by just reading this one i now know what the problem is.


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## wirenut1110 (Feb 12, 2008)

No problem:thumbsup: 
If you ever need information on any other generator just go to http://generac.com/ click on "service & support" then on the left click on 
"owners manual search' and enter the model #. If you just want info on a transfer switch, you'll need a serial # too.


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## MDShunk (Jan 7, 2007)

wirenut1110 said:


> I was just shooting out the simple version, I'm sure it may be a little more complicated than that.


Yeah, I know. I'd led to believe that the generac generator itself does the voltage and frequency proving, then sends the 12V to the transfer switch to transfer. Call me old-school, but I like a generator to just be a generator, and the transfer switch to be the brain.

Seimens and Generac is the same thing with a different label anyhow, right?


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## wirenut1110 (Feb 12, 2008)

calimurray;85329 by just reading this one i now know what the problem is.[/quote said:


> Care to share what the issue is/was?


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## calimurray (Apr 29, 2007)

From what I can see with the schematics shown is in they have 28 & 194 designated for the 12vdc feed, on the transfer switch the wires were set in there original location and the 194 terminal was not being used. 

They left the original wiring and installed the new generator without wiring the transfer switch, according to the drawing 
the N1 and N2 are your 240vac feed and you got 28 and 194 set for the 12vdc, 

If I correct the wiring to follow the drawing then hopefully the fuses won't blow and the damn switch will operate otherwise we may need a new switch.


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## miketrek (Nov 13, 2008)

Hey there guys
Funny, just searching for this same thing. I have a customer that had an old generac generator 35kw and got a new transfer switch from generac. No model number can be found on the generator, so I told him I'd look into it. So here I am. Even though its not the same problem it might be now, once I test it out.
Thanks guys
MD-why dont you like generac? I like them. simple over all, runs nice, I like the electrical parts. but I dont really use any other ones......as a electrical contractor.
Thanks again
MIKE


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## B4T (Feb 10, 2009)

This thread is wayyy too old and should be closed.. :no:


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## brian john (Mar 11, 2007)

miketrek said:


> MD-why dont you like generac? I like them. simple over all, runs nice, I like the electrical parts. but I dont really use any other ones......as a electrical contractor.
> Thanks again
> MIKE


Um junk, GENERCRAP, the YUGO of generators, shall I go on.

And the ATS leave a lot to be desired IMO.


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## ampman (Apr 2, 2009)

just thinking mabye it was the FUSES


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## micromind (Aug 11, 2007)

brian john said:


> Um junk, GENERCRAP, the YUGO of generators, shall I go on.
> 
> And the ATS leave a lot to be desired IMO.


I'm of the same opinion, at least for the smaller ones.

Not a very good design, and even worse, the gens are not compatible with other transfer switches, and the transfer switches won't work with other gens; well, not without modifications anyway. 

The bigger ones (over 100KVA) are ok. Most of them I've seen have either Perkins or John Deere engines and Marathon generator ends.


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## Jlarson (Jun 28, 2009)

micromind said:


> I'm of the same opinion, at least for the smaller ones.


Same opinion here too. 

Their whole deal where they put the "brains" in the genny instead of the transfer switch really turned me off. It pretty much eliminated them as an option for small utility sites and things like that. Being able to patch in a temporary generator to the xfer-switch is an important option in my world.


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## brian john (Mar 11, 2007)

Jlarson said:


> Same opinion here too.
> d.


I was an ASCO service rep for 15 years so my opinion is somewhat slighted and have worked on Zenith, Russell and Onan for better than 30 years...Just do not care for the Design of the ATS's. As for the generators the larger ones are better and personally I fell all the new controls on generators complicates a simple product.

There was a time I could get just about any engine to start, now with proprietary software and all the sensors one REALLY has to have the proper training.


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## r_merc (Jul 5, 2008)

seimens is just a rebranded Generac the wireing has changed a little but they should be compatible


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## micromind (Aug 11, 2007)

brian john said:


> I was an ASCO service rep for 15 years so my opinion is somewhat slighted and have worked on Zenith, Russell and Onan for better than 30 years...Just do not care for the Design of the ATS's. As for the generators the larger ones are better and personally I fell all the new controls on generators complicates a simple product.
> 
> There was a time I could get just about any engine to start, now with proprietary software and all the sensors one REALLY has to have the proper training.


Agree completely.

I don't know about anyone else, but with all these new-fangled electronic controls I've seen more failures than before. 

I think that emergency systems need to be kept as simple (and therefore reliable) as possible.


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## brian john (Mar 11, 2007)

micromind said:


> Agree completely.
> 
> I don't know about anyone else, but with all these new-fangled electronic controls I've seen more failures than before.
> 
> I think that emergency systems need to be kept as simple (and therefore reliable) as possible.


We have had a few sites that lost critical load due to a simple sensor, failing.

KISS for emergency. KIS for standby?


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