Over Speed light flashing on a 43903

Generac, Guardian, Honeywell, Siemens, Centurion, Watchdog, Bryant, & Carrier Air Cooled Home Standby generator troubleshooting and repair questions
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majewskitj
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Tue Jul 02, 2019 8:20 am

 Mon Jul 01, 2019 9:16 pm

- Fuel supply type (NG or LP), size of pipe and length of gas run: Natural Gas
- Model and Serial number of generator: 0043903 serial # 3943934
- Problem you're having, what have you done so far to try and resolve the issue : Over Speed Light flashing
- Do you have access to testing equipment such as a digital volt meter and fuel pressure gauge: Yes
- How long has the problem been happening, during cold/warm weather? Two weeks
- What has the maintenance been like for the generator (a lot of problems are due to a lack of maintenance): Oil change / Oil filter / check air filter - clean. Have not done anything with the spark plugs

Gen Set went through normal weekly exercise cycle and have the over speed light flashing. Checked the measured Ohms on voltage regulator (wires 0 and 4) got 23.4 Ohms across. Red light goes on at voltage regulator while engine starts and runs. Disassembled to brushes and slip rings. Cleaned slip rings with brake cleaner and 320 emery cloth. Did not do anything with brushes but made sure the springs were working and still had a lot of graphite left on them. Reassembled and fired gen set up and still get the over speed flashing in manual mode. Any ideas of where to go next? If it is to replace the ignition coils what is the part number that matches this engine? Any help would be appreciated.

Thanks,

Tom
Chris
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Tue Jul 02, 2019 9:06 am

Hey Tom,

What is the voltage output on the unit when it's running and goes into flashing overspeed?

Thanks for starting the new topic also, I removed the other one :cool:
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majewskitj
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Tue Jul 02, 2019 8:51 pm

During the 10 sec it spiked at 44V and went to zero by the time it shut off. Checked the Excitation circuit breaker with ohms and it is open no continuity.
Chris
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Tue Jul 02, 2019 10:10 pm

A bad DPE breaker would certainly do it, however the LED would not be lit if the DPE breaker were bad. A bad AVR may have wiped out the DPE breaker
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majewskitj
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Wed Jul 03, 2019 9:18 am

So is your recommendation to buy the DPE Breaker and a Voltage Regulator? Is there any test that can confirm the voltage regulator is bad especially knowing the DPE is bad or does the DPE have to be replaced first and hope it does not get fried by the voltage regulator when generator is put in manual mode? Does Gentek sell these parts? I put in the part numbers from the owners manual and do not get any hits.
Chris
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Wed Jul 03, 2019 3:50 pm

If the AVR has the white colored plastic adjustment screw, I would change it out for the one listed below with the brass adjustment pot, just to avoid problems down the road if they aren't there already...
Yes I sell these parts. The parts site is constantly getting updated with parts, so there are some things that aren't on there yet :sad:

The voltage regulator is here: https://shop.gentekpower.com/products/g ... ulator-avr
The DPE breaker for this unit is here: https://shop.gentekpower.com/products/g ... aker-3-amp
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
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majewskitj
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Sun Aug 25, 2019 3:25 pm

Replaced both the AVG and DPE components. The generator now runs in manual. When I put in auto mode it starts up in about 16 sec but never turns off. Got the Green light flashing and the red lights flashing. Tried to set the exercise mode but it keeps running. Any hints whaat I need to try next?
Chris
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Sun Aug 25, 2019 5:21 pm

That is a different issue all together and you'll also notice that your transfer switch is transferring too...

The flashing green light is telling you that your generator thinks you have an outage.

This could be a bad N1 or N2 fuse, bad wiring, bad transformer or even a bad PCB.

Start with testing for 240V power at the generator's N1 and N2 terminals.
Generac tech for over 12 years. I'm here to help!
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majewskitj
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Sun Sep 01, 2019 4:10 pm

N1 fuse was blown. Replaced and in business again. Reset the exercise mode and green solid light.

Thanks for all your help troubleshooting. It is great to know there are people like you that are willing to give the extra helping hand!

Tom
Chris
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Mon Sep 02, 2019 5:55 pm

Thanks for keeping us updated! Glad to hear it's fixed!
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
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