Generac Over crank

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Ceilidh44
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Morning, have a freindly competitor that has reached out for some help, below is the email he has sent me, sorry he didnt send model or serial numbers.

I have three units, Liquid cooled 36 kw, 48 kw, 60kw that have all started to act up this year. One is brand new (60kw) and the others are two years old. Never a problem but all of a sudden every week on self test they over crank. Propane. Not on quiet test. We show up press manual and they start right up.
Even if we change the self test to when we are there they start.
Cold weather kits installed
Of course when we are no where around they fault out when self test.

Possessed I tell you.

Random events, different temps, warm cold doesn't matter. I just went out and cleared the 36kw again this morning. Fuel pressure good, full tank, cleared error and started up right away, yet self test over cranks.


I have not experienced this issue and not sure what it would be.
Chris
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This is very much deja vu for me... I saw this same thing posted in a Facebook group I'm in by Alex. I did respond there as well. If you'd like, send me a PM and fill me in about what's going on and why he asked you and now you're asking me haha! :ahh:
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Clays99
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Had this exact same problem on two units. First one drove me crazy for a while till I decided to use a Kohler fix. Polish the rotor where the brushes ride. Problem solved. Second one did the same fix the first time and no more problems.
Chris
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Kohler may be different with regard to how their units detect running, I'm not sure? The slip rings won't have anything to do with overcrank on these particular style units. You'd get an Undervoltage alarm or something similar if there were a voltage issue with them.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
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Loopyhunter
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I am having this exact same issue on a 48kw generac. Only a few months old. The last one before they changed the engine and model number.
Chris
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What's the fuel pressure and have you monitored it overnight?

What's the fuel install look like?
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
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Loopyhunter
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Sorry for the delay. I figured I would get a notification of a reply.

This is a generac 48kw RG04854ANAX
installed in December 19
LP distance from lp secondary regulator
6 foot of black pipe 1" 2 90s
Regulator Rego 935k btu

On weekly exercise it will fail on overcrank.
First the first month of operation no issue.
Gas pressure is set at 11 inch of WC when starting up will fluctuate less than 1 inch if wc.
Under full load bank load regulator drops down to a little over 8 but has no issues.

I cannot get the overcrank condition to replicate after it has already happened.
Tried setting exercise timer to different days and times even when on site. Tried seeing exercise timer through mobilelink and by hand. (Did this to just rule that out since home owner changed this setting on the website the week prior to a lot of these weird errors) One week it worksfine the next it failed. Since January it has failed exercise 8 out of 10 times. Regardless of weather.
Kinda been pulling my hair out on this one.

I have increased gas pressure to 12.5 inches this week.
I have replaced regulator, purged lines with gas pressure.
This last week it did something different and gave me rpm sense loss error.
Check the sensor it passes all tests.
Generator started up normally again.
Unit has battery heater and coolant heater.

Have any suggestions it would be much appreciated.

I did not install the gas on this generator so it is a bad situation for me not being able to put my exact finger on the issue.

Has this issue on or off of quiet test.
Chris
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I would install a manometer into the fuel system and monitor fuel pressure over 24 or 48 hours and see if it's creeping up without you knowing. Too high of a pressure and it will hold the fuel solenoid closed.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
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