# Generac Advice



## Rollie73 (Sep 19, 2010)

OK all you Generac gurus. I'm looking at you mcclary:laughing:. 

I have a 16kw generac that is giving me intermittent start issues. Last time it happened, I tried starting the damn thing in manual and it shows battery issue but when I took the battery out and brought it to the parts store where it was purchased, they did a load test and a voltage test and it was fine. Tested at 100%
When it fails to start it shows, error code 1504(?) RPM SENSE LOSS. 

SO....if I have a good battery and it will not start and it shows RPM SENSE LOSS when it fails to crank over.......where do I go from here?


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## Rollie73 (Sep 19, 2010)

Damn.....I miss-spelled Generac in my thread title.:laughing:


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## nrp3 (Jan 24, 2009)

Now I have to slog through the snow to get to the book...


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## nrp3 (Jan 24, 2009)

No crank or no run? I don't see 1504, but see 1501, 1505, 1511, or 1515 RPM sense loss. Doesn't mean that numbers not there either.


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## Rollie73 (Sep 19, 2010)

nrp3 said:


> No crank or no run? I don't see 1504, but see 1501, 1505, 1511, or 1515 RPM sense loss. Doesn't mean that numbers not there either.


I could be wrong on the number, I didn't write it down.....but the message is RPM sense loss. Its certainly 15XX....:laughing:


It won't crank if I try to run it in manual either.


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## nrp3 (Jan 24, 2009)

Loose connection, starter relay, starter itself.


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## Rollie73 (Sep 19, 2010)

OK Thanks for the suggestions. I'm thinking maybe the starter relay???? Good spot to start I guess. 

Been a lot of rain and then quick freeze ups here lately. Maybe I have an intermittent problem with water in a connector freezing up.


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## nrp3 (Jan 24, 2009)

It goes through a relay before it makes it to the starter solenoid. That relay is a little black cube with four wires near the controller. Looking for battery voltage at the coil of that relay first, wire 56, then battery voltage at coil at the starter solenoid, wire 16. This would be when you are attempting a start. Be that you are talking a new unit, you can call one of us service guys for warranty too.


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## Rollie73 (Sep 19, 2010)

I will be calling for warranty service. Brand new unit. Less than 15 hrs run time. 

Do you want to make a run up to Nova Scotia here in Canada and do the warranty work for me??:laughing:


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## nrp3 (Jan 24, 2009)

If I were closer, I'd be happy to.


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## Rollie73 (Sep 19, 2010)

I appreciate the help so far NRP......I will check for voltage to the starter and go from there. Its a brand new unit and under warranty so I'm going to do a few basic checks then let the authorized service guy do his end of things.


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## McClary’s Electrical (Feb 21, 2009)

Can't be sure without looking but, a couple notes

1) too low gas pressure
2) weak battery
3) bad starter, cranking too slow
4) bad sensor


I listed these in order of likelihood. ....


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## Rollie73 (Sep 19, 2010)

mcclary's electrical said:


> Can't be sure without looking but, a couple notes
> 
> 1) too low gas pressure
> 2) weak battery
> ...


Will it crank over with low gas pressure?


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## McClary’s Electrical (Feb 21, 2009)

Rollie73 said:


> I will be calling for warranty service. Brand new unit. Less than 15 hrs run time.
> 
> Do you want to make a run up to Nova Scotia here in Canada and do the warranty work for me??:laughing:


I missed that this is brand new. Make sure that the selection between lp and ng is correct. Also, there is a physical selection for this, and an electronic selection for this. So there are two places that you need to select fuel type. 

Secondly, under load, you should have 10-14 inches of water column. If less, the machine will not run properly, or may not start.


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## nrp3 (Jan 24, 2009)

Cranky yes, starty no. Though in this case you might end up with overcrank.

Saw a few of those at Thanksgiving. Will start and run but die eventually. (gas in wrong position).


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## Rollie73 (Sep 19, 2010)

mcclary's electrical said:


> I missed that this is brand new. Make sure that the selection between lp and ng is correct. Also, there is a physical selection for this, and an electronic selection for this. So there are two places that you need to select fuel type.
> 
> Secondly, under load, you should have 10-14 inches of water column. If less, the machine will not run properly, or may not start.


Yep brand new McClary.....it did run perfectly. I ran it numerous times under load. I did set it up for LP gas already. It just recently started with this issue. It has done its weekly start up every Sunday for the last month and a half but not this week:no:



nrp3 said:


> Cranky yes, starty no. Though in this case you might end up with overcrank.


I get no crank at all.


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## McClary’s Electrical (Feb 21, 2009)

Rollie73 said:


> Yep brand new McClary.....it did run perfectly. I ran it numerous times under load. I did set it up for LP gas already. It just recently started with this issue. It has done its weekly start up every Sunday for the last month and a half but not this week:no:
> 
> 
> 
> I get no crank at all.


Have you tried to start it manually? If so, I would bet is a bad solenoid, or bad starter.


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## nrp3 (Jan 24, 2009)

Start with the wiring, look for 12v at the black relay and if thats good 12v at 16 at the starter solenoid when trying a manual start.


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## Rollie73 (Sep 19, 2010)

mcclary's electrical said:


> Have you tried to start it manually? If so, I would bet is a bad solenoid, or bad starter.


Yep tried manual start.

EV Controller shows....

1. Manual start
2. Cranking.....attempt #1
3. Error Code 15XX..........RPM sense loss.


In that order although the exact wording may be slightly different.


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## McClary’s Electrical (Feb 21, 2009)

Rollie73 said:


> Yep tried manual start.
> 
> EV Controller shows....
> 
> ...


Yep well you've got either a bad starter relay or bad starter. Verify voltage is making it through your relay. If it is, you know you have a bad starter, double verify that by using jumper cables and putting 12 volts right on the starter.


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## Rollie73 (Sep 19, 2010)

Thanks guys. I appreciate that. I will try it all out tomorrow.


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## jarhead0531 (Jun 1, 2010)

There are two potential issues that could cause a problem. First thing we really need to know is the controller type. There is a firmware update for evolution controllers for this very issue if I am not mistaken. Nope, I'm wrong, that is undervoltage.

The is also another bulletin concerning rpm sense loss issues that are caused by low temps. In my experience extended periods below 15-20 degrees will cause this error. Something to do with condensation around the brushes on rotor freezing and causing poor contact. By the some miracle the generator will work fine once the temp gets above freezing.

Just another thing to be mindful of.


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## Pete m. (Nov 19, 2011)

Rollie73 said:


> Damn.....I miss-spelled Generac in my thread title.:laughing:


No you didn't:whistling2:

Pete


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## brichter (Oct 26, 2009)

Just a guess but have you cleared the error code then tried to start manually?


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## Rollie73 (Sep 19, 2010)

brichter said:


> Just a guess but have you cleared the error code then tried to start manually?


Yep....sure have. Didn't get there today. Try to make it tomorrow.:thumbsup:


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## nrp3 (Jan 24, 2009)

Any luck?


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## Rollie73 (Sep 19, 2010)

nrp3 said:


> Any luck?


Sure did nrp. Thanks to the advice from both you and mcclary I tracked it down to be a bad start relay. I verified voltages at the two points you told me to check. Had voltage at wire 56 but nothing coming from the relay to the starter solenoid.
I then did what mcclary suggested and jumper'ed 12 volts to the starter and the unit cranked over and offered to start. 

It didn't run because of a no fuel situation. It seems the frost in the ground heaved the propane tanks that are about 300' away and kinked the line coming from the tanks.

So I had two problems out there. I had a local (300 km away) generac service guy replace the relay for me and they installed a new propane line yesterday so we are all good now.

Thanks for the help guys:thumbsup::thumbsup:


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