Generac Troubleshoot

[ElectricianJeff]

I am trying to toubleshoot a whole house generator system I installed last spring and am kinda at a deadend so I am trying to summon the wisdom here to figure out whats wrong.

The system consists of a 16 kw natural gas Generac with a Guardian 16 space ATS. All material was provided by the customer that also happens to be a real good customer of mine. The customer wanted the generator out by his detached garage so I piped the conductors and control wires out about 100' from his home. I used #4 conductors to account for any voltage drop and 18/4 for the control wiring. After reading later on this forum I regret using the 18/4 and had actually planned on repulling everything this spring at my expense.

The system was functioning fine all summer. However, now when you pull the poco main the units fires as required. I am getting 240 volts at the generator side of the transfer switch but the switch will not automatically transfer power. I can manually transfer and everything works fine. When I close the main the switch works and the unit shuts down after running the required cool down time.

I was there last week and I checked all connections, fusing and trouble lights and everything appeared fine. I was suspect of the control wiring so yesterday I ran #10 thhn from the switch to the unit for the 2 240 volt control wires. This made no difference in the performance of the system.

I have little experience with controls and would appreciate any advice anyone would care to offer as where to look from here. I am suspect of the upper solenoid but I am alittle uncomfortable bench testing it. I have attempted to includ a picture to facilitate any discussion that might occur.

 

[LarryFine]

Jeff, I'd start with measuring for voltage at the solenoid terminals, especially if the ATS switches back to utility power properly. That will confirm whether the solenoid is burned out, or the control circuitry is malfunctioning.

You could also try temporarily jumping one solenoid's wires to the other solenoid (with original wires disconnected, of course.) As with most troubleshooting, use a process of elimination, starting with what's easiest to check.

Remember, it worked at one time. Something has changed. You need to find out what, and restore it back to original operational condition.

 

[Bobhook149]

Do you have 12v at the transfer switch when poco power is removed and gen is started? And were is the transfer wire on this unit?

 

[hunt4679]

The last three generacs I installed had a set of 240 volt sensing wires and a set of 12 volt control wires to make it operate I believe the 12 volt wires work the solenoids

 

[ElectricianJeff]

Jeff, I'd start with measuring for voltage at the solenoid terminals, especially if the ATS switches back to utility power properly. That will confirm whether the solenoid is burned out, or the control circuitry is malfunctioning.

You could also try temporarily jumping one solenoid's wires to the other solenoid (with original wires disconnected, of course.) As with most troubleshooting, use a process of elimination, starting with what's easiest to check.

Thanks Larry, something I hadn't considering doing. This test would eliminate the solenoid as the culprit.

What voltage makes the solenid do its thing? 12V or 240V, I'm not sure. I just find it hard to believe that the solenoid has failed with less than 15 uses with setup and a few power outages that have occured since installation.

One thing I forgot to mention, when this unit was installed both the fuses in the transfer were no good, I replaced them and it seemed to be happy. I chalked it up to damaged in shipping. I checked them first in my original troubleshooting visit and they were fine.

 

[ElectricianJeff]

The last three generacs I installed had a set of 240 volt sensing wires and a set of 12 volt control wires to make it operate I believe the 12 volt wires work the solenoids

Exactly what I have.

 

[hunt4679]

I also think there is a fuse in the generator for the 12 v control

 

[ElectricianJeff]

I also think there is a fuse in the generator for the 12 v control

if its the one by the on/off/auto switch I checked it also.

 

[charlietuna]

The last one i did had AC voltage on the transfer switch solinoids. Re-test the system and read the voltage at the emergency coil's solinoid -- if you have voltage and no transfer the coil's probably shot. From what you have explained --the rest of the control system is functioning correctly.

 

[ahp691]

Transfer switch problem

Transfer switch problem

I had a similar problem with a Briggs and stratton 20 kw generator and 200 amp transfer switch. The generator was close to the house. The system worked fine when we installed it but a few months later during a power failure it didn't transfer. The generator started but did not transfer. When I came out I opened the main, the generator started but failed to transfer, so I manualy transfered it. Then closed the 200 amp main. the transfer switch transfered back to normal power, then the generator cooled down and shut off. I opened the 200 amp main, the generator started and I manually transfered it again. I then swapped the solenoid wiring and found I had a bad coil. I called The support line and they agreed and sent me a new solenoid set. I swapped them out and its been fine now.

 

[ceb58]

I have a generac RTS switch doing the same thing. Check the volts on the normal coil. It should be 240v. Then turn main off and put leads on the emergency coil. When the gen cranks you should read no volts for a short time. The relays and timers are breaking one leg of the 240v. After the timers do there thing and the relays switch you should have 240v. When the gen. cranks you should read 120v from one coil lead to ground. If you are getting the 240v to the coil then the coil has gone bad. If the gen is cranking on power outage then the control wires are doing there job. The ATS is the "smart" one in the group it tells the gen.set what to do crank, shut down. The ATS has the "brains" to start the set, warm up time before trans, re-transfer, cool down and shut down.

 

[goldstar]

I'm not sure if this will be helpful or not or even whether it pertains to your situation but I'll say it anyway. The units come with a 30' whip that contains the generator power wires and the (4) sensing wires. I had a situation like yours where I had to extend the length of the whip some 40'. I was told by another dealer to make sure the sensing wires are not wrapped in a spiral around the generator power wires as the induction will cause the unit to malfunction. I don't know if there's any truth in that but if you try some of the solutions the others have mentioned and have no luck try rolling out a length of 12/3 RX cable and bypass that portion of the wiring and see if that works.

Good luck

 

[ElectricianJeff]

I had a similar problem with a Briggs and stratton 20 kw generator and 200 amp transfer switch. The generator was close to the house. The system worked fine when we installed it but a few months later during a power failure it didn't transfer. The generator started but did not transfer. When I came out I opened the main, the generator started but failed to transfer, so I manualy transfered it. Then closed the 200 amp main. the transfer switch transfered back to normal power, then the generator cooled down and shut off. I opened the 200 amp main, the generator started and I manually transfered it again. I then swapped the solenoid wiring and found I had a bad coil. I called The support line and they agreed and sent me a new solenoid set. I swapped them out and its been fine now.

This is my exact scenerio. I will try swapping the solenoid wiring as above when I am there next week.

Now I will show my ignorance, is the coil the same as the solenoid? If so, then I would assume the "emergency coil" is the one at the top in photo since it is the one that engages upon power failure.

Also, is searching this subject I recall that Generac is not real electrician friendly and will only refer you to one of their authorized dealers when you call. Does this still hold true?

Thanks for all the help so far, btw.

 

[masterinbama]

I had a 1500 KW Cat do that. It turned out to be one of the micro switches not closing upon transfer to utilities. Would not allow power to the emergency solenoid.

 

[Cold Fusion]

...Now I will show my ignorance, is the coil the same as the solenoid? If so, then I would assume the "emergency coil" is the one at the top in photo since it is the one that engages upon power failure. ...

Take a look in the manual that came with the generator. It should tell you the location of the components. It might even have a troubleshooting section and a wiring diagram.

Without a wiring diagram you are pretty well troubleshooting by Easter Egg hunt.

cf

 

[ceb58]

This is my exact scenerio. I will try swapping the solenoid wiring as above when I am there next week.

Now I will show my ignorance, is the coil the same as the solenoid? If so, then I would assume the "emergency coil" is the one at the top in photo since it is the one that engages upon power failure.

Also, is searching this subject I recall that Generac is not real electrician friendly and will only refer you to one of their authorized dealers when you call. Does this still hold true?

Thanks for all the help so far, btw.

Coil, solenoid same thing. If in the photo the ATS is in normal utility position the one on the bottom is the emergency coil. When utility drops out and power is applied to the emergency coil it magnetically pulls the the bar down rocking the contactor to the emergency feed.
As far as Generac, no they are not electrician friendly. You must be an authorised dealer-service personal to even talk with some one in tech. support.

 

[hunt4679]

Just a little FYI generac is letting everyone put there stickers on their units and they are not fun to wire!

 

[goldstar]

Also, is searching this subject I recall that Generac is not real electrician friendly and will only refer you to one of their authorized dealers when you call. Does this still hold true?

You bet. Don't expect to get any factory help unless you have a dealer registration # and even with that, unless you've had some of their training you won't get too far either.

 

[hillbilly1]

On the small generacs, the brains are in the generator, not in the transfer switch. The 18-4 you ran has 240 AC volts on one pair for the sense voltage and the charger power. The other pair has 12 volts DC which powers the clear cube relay in the transfer switch, this is energized when the generator is up to speed and ready to transfer. The power for the coil (solonoid) is derived from the source available, if the cube relay is de-energized, it supplies power from the utility source to transfer to normal. If the cube relay is energized, it supplies the the coil (solenoid) that transfers the switch to generator power. If there is no 240 volt power from the generator(generator breaker tripped, fuse in transfer switch blown) it will not transfer. That being said, Generac has had issues with the coils going bad, usually due to incomplete transfer. The coils have clearing contacts (those microswitches you see on the side of the switch) which turn power off to the coil once the switch is closed. If the voltage is too low from the generator, sometimes the switch fails to close completely leaving power on the coils, thus destroying it.