120 VAC Shuts Off When Running Both AC's On Genny

[ellisjte]

They are 13,500btu dometic units with heat strips.  They seem to still work pretty good considering they appear to be original.  But it hasn't got real hot here in FL yet since I bought it.  Hope they keep up since we plan to do state park trips all summer too.

The rear one was rebuilt according to the previous owner, I may dig up the ticket to see just what that entailed.  I thought it was typically more economical to replace.

On a more serious note, everyone should own a desert eagle!  Mostly useless but very accurate for a pistol.  I can keep most of the rounds on paper at 100 yards (on a rest) Though I do tend to get less accurate after 3 or 4 mags.  It's got some recoil!  Not as bad as a 500s&w though. Tons of fun at the range and usually starts a few conversations.

[wildebill308]

Well back to the non gun problem. I am inclined to think you are on the right path. Look at what was done to the AC. This is mostly guessing with out hands on or schematics for your coach, but. It kind of sounds like something (suspicious of the repaired ac) is causing a high load event causing a self resetting circuit breaker to trip. After things cool down it resets and the process starts over. It would be helpful to know what the amp load is when it shuts down. 

Bill

[ellisjte]

I'm in agreement with the suspicion of rebuilt AC's, but you'd think I'd be tripping breakers or at least seeing the same symptoms on shore power.  I'm still leaning genny control board but we'll see what my Dad's fancy multimeter and amp meter have to say at various points in the system.  The fun part will be waiting around for it to show out.  Ain't electrical Gremlins fun!

[wildebill308]

14 minutes ago, ellisjte said:

I'm in agreement with the suspicion of rebuilt AC's, but you'd think I'd be tripping breakers or at least seeing the same symptoms on shore power.  I'm still leaning genny control board but we'll see what my Dad's fancy multimeter and amp meter have to say at various points in the system.  The fun part will be waiting around for it to show out.  Ain't electrical Gremlins fun!

Well here again I don't know but suspect you can pull more power on shore power than with the generator. When you check the amp load see if you can check each ac  and see/make shure they are on separate circuits.

Electrical Gremlins are as much fun as shooting a 2" scandium S&W 44mag.

Bill

 

[huffypuff]

 

ellisjte, I hate to say this but that the same problem I experience this winter.  The wiring harness was going bad to the inverter in the generator and soon took out the inverter a 4K repair.  Yank the generator out of the coach, pull the panels and check the connection of harness to inverter before it's too late.  It can soon go to no 120 at all.  Mine had melted at the connection.  

[ellisjte]

8 minutes ago, huffypuff said:

 

ellisjte, I hate to say this but that the same problem I experience this winter.  The wiring harness was going bad to the inverter in the generator and soon took out the inverter a 4K repair.  Yank the generator out of the coach, pull the panels and check the connection of harness to inverter before it's too late.  It can soon go to no 120 at all.  Mine had melted at the connection.  

Yikes!  Yeah I'd like to avoid that if possible, previous owner just replaced the inverter a year before I bought it, it would be a shame to fry it!  Not sure if wiring rotting out would be as predictable as what I'm seeing but with looking at for sure!

[ellisjte]

25 minutes ago, WILDEBILL308 said:

Well here again I don't know but suspect you can pull more power on shore power than with the generator. When you check the amp load see if you can check each ac  and see/make shure they are on separate circuits.

Electrical Gremlins are as much fun as shooting a 2" scandium S&W 44mag.

Bill

 

I wondered that myself, that limit, if it exits would have to be between the genny and ats I believe, since the past the ATS it's the same if you're on shore or genny.

Yeah those things bite!  Best left for emergency use only!

[huffypuff]

I'm not sure what inverter you are talking about but what I stated is the inverter inside the generator itself. The generator makes DC volts and has to be change to AC voltage.  It is the AC voltage wires that had bad connection inside the generator

[manholt]

Blake, did you also forget where you live?

Wow.  .50 and .44, both bad...think Bear hunting in Alaska on the .44 & .357

[ellisjte]

43 minutes ago, huffypuff said:

I'm not sure what inverter you are talking about but what I stated is the inverter inside the generator itself. The generator makes DC volts and has to be change to AC voltage.  It is the AC voltage wires that had bad connection inside the generator

Yeah I should have slowed down to think about that for a second, the other inverter isn't involved here at all. 

No way to look at that w/o dropping the whole thing out?

[blakeloke]

1 hour ago, manholt said:

Blake, did you also forget where you live?

Wow.  .50 and .44, both bad...think Bear hunting in Alaska on the .44 & .357

Nope!  We enjoy all things outdoors and I could go on forever talking calibers and the tools that shoot them!

I was including myself in the Texans comment. Hehehe

 

[huffypuff]

4 hours ago, ellisjte said:

Yeah I should have slowed down to think about that for a second, the other inverter isn't involved here at all. 

No way to look at that w/o dropping the whole thing out?

You have to get the panels off the generator and looking near the winding there be a box with fins on it.  Since the panels are off put a new water pump belt on.  You may have to remove the generator for the job as mine had to come out because it didn't slide out enough.  

[manholt]

Another thought (cheaper) is that your start relay in your AC is sticking or going out.  We had 2 other Post's on this in Feb. under Electrical.

[kaypsmith]

Here is a situation similar from earlier this year.

 

[ellisjte]

Ok quick update.

Since it's going to be another week before I can get over to Dad's to borrow his gear I figured I'd take a look at the genny control board.  There's a heatsink bolted to a chip in the board that had vibrated loose, after seeing that I was sure the board was my problem.  Makes sense an overheating chip could cause my issue right?  I installed the new dino board and I'm getting the same results. 

 I watched the inverter control panel when it kicked out to get an idea of what's going on.  When it dropped it was all at once, not a gradual loss.  Then before everything came on again the voltage would flash 65 or 70 then back to 0.  It did this 3 or four times and took about 5 minutes to come back.  Then 10 minutes later the cycle starts over again.  ( Takes about 30 minutes from when I turn the second AC on to kick out initially)

So I'm leaning ATS now but I'll wait till I can actually measure what's happening before I buy more parts... Although I may go ahead and do new starting caps on the AC's since the front one is almost surely 20 years old and likely not very effective anyway.

It's an esco ATS, I plan to call them and see if that's an issue they've heard of before.

Thanks for all the input everyone!

 

[huffypuff]

1 hour ago, ellisjte said:

Ok quick update.

Since it's going to be another week before I can get over to Dad's to borrow his gear I figured I'd take a look at the genny control board.  There's a heatsink bolted to a chip in the board that had vibrated loose, after seeing that I was sure the board was my problem.  Makes sense an overheating chip could cause my issue right?  I installed the new dino board and I'm getting the same results. 

 I watched the inverter control panel when it kicked out to get an idea of what's going on.  When it dropped it was all at once, not a gradual loss.  Then before everything came on again the voltage would flash 65 or 70 then back to 0.  It did this 3 or four times and took about 5 minutes to come back.  Then 10 minutes later the cycle starts over again.  ( Takes about 30 minutes from when I turn the second AC on to kick out initially)

So I'm leaning ATS now but I'll wait till I can actually measure what's happening before I buy more parts... Although I may go ahead and do new starting caps on the AC's since the front one is almost surely 20 years old and likely not very effective anyway.

It's an esco ATS, I plan to call them and see if that's an issue they've heard of before.

Thanks for all the input everyone!

 

 

I made the test easy when I lost 120 power.  I  went to the generator output cover and found 0 voltage there.  Same at the ATS no 120 there.  The readout from the EMS panel would show 30 amps but none being used even with the generator shut off.  The EMS panel would reset as soon as I plugged into shore power.  Funny how electronics would act when not getting the correct voltages.   

[ellisjte]

Another update,

I borrowed a multimeter that measures voltage, freq, and amperage.  Popped the cover on the ATS started the genny and waited, and waited.. with the cover off it took about an hour to start showing out.  Normally it takes about 25/30 minutes. That tells me something is heating up in the ATS and causing the issue.  When it kicked out I was still getting 120 on each leg where the genny feeds in and 0 on the other side.  About once every 30 seconds it would try to switch and fail.  Probably the circuit board going bad, could be exacerbated by bad contacts.  

Freq looked good, never checked amp draw since I don't think that's my issue and I couldn't find a good place to clamp on the genny feed.  

I'm convinced it is the ATS, how bout y'all?

Ordered an exact replacement for 215 shipped.  It's an ESCO ES50M-65N.  I'll update after I swap it out.

[kaypsmith]

It seems to me also that the ATS is your culprit based on your test. The circuit board in the ATS is a very simple device that  causes a delay in the switch making the transfer until the generator has a chance to come up to speed to avoid damaging the generator. Overheating of this timing device can cause failure. Overheating in the ATS is most commonly caused by loose wiring connections inside the ATS, but I would also look at placement of the ATS making sure that it is not too close to the genny or any exhaust of same. Brett stated in an earlier post that he didn't feel that there would be any off and on of the breakers, as they are manual and need physical resetting, and I agree with that conclusion especially since the AC seems to come back alive after a possible cool down.

[ellisjte]

Well, I finally got time to go out and install the new xfer switch... and the dang L1 connector was installed sideways.  No big deal just unscrew it and turn it around right?  Well normally it shouldn't be, but it must have been 1700 on Friday when they assembled that one because the screw that holds it to the contactor was stripped out already.  Now I have to wait for a new one.  =/

Hope to be able to get her in weekend after this one and confirm the fix.

[ellisjte]

Ok finally!  Got the new xfer switch in and ran both AC's on the generator for almost 2 hours and it didn't miss a lick.  Kind of a pain to install but I got it done.  Thanks to everyone for their input.

[dickandlois]

Thanks for posting that the issue has been fixed. Every bit of information makes the forum better for all who visit.

Rich.

[ellisjte]

Ok so guess what.  The xfer switch didn't cure the issue.  It turns out it just had a better tolerance for the excessive current the roof airs were drawing, I'd lose power after about 2 hours vs the 45 minutes to 1 hour I was getting before.  Testing revealed that after the AC's were running for some time they were drawing in excess of 20 amps each.  Once both AC's got going real good and both compressors would try to cycle it would kick out.  Not sure how the breakers didn't get tripped exactly, could be it was just under the tolerance of the breaker... I'll look into that soon.  In fact I may be better off just replacing them.

The units still cooled well, but after 20 years I guess it was just their time.  Most likely just a matter of time until I started having issues on shore power too, or a fire..

I just dropped in two Coleman mach 15 units to replace them and I was able to run both AC's for over 4 hours.  It kept the coach a breezy 74 degrees when it was right at 100 and sunny down here in FL. 

Pretty easy install since there's no ducting or thermostat to deal with.  Hardest part was getting the new units on the roof and maneuvering them around.  Luckily my Dad came through at his RV resort with a guy on a front end loader.  That made it a lot easier!  Cost me 20 bucks and a cold beer.  I would have paid someone to do it but everywhere I called wanted 3 hours of labor PER UNIT!?  Total cost for install between $700 and $900  That is just silly for an easy job that should take an experienced RV tech 2 hours tops.  It took me about 3 and it's the first time I'd ever attempted one.  I got both units and all the pieces for $1800 from Lazy Days in Seffner, which surprisingly was not a lot more than the online prices I saw.  I'd rather deal locally with something like that since shipping those things back and forth in the event of an issue wouldn't be fun.

Anyway, the whole point of my post is to let people know to check the draw on old AC units... or risk running around in circles like I did.  I'm pretty sure someone mentioned that pretty early on but I'd convinced myself the current draw couldn't be that bad for a couple of reasons.

1. It was doing fine on shore power

2. Time to kick out was longer if the cover was off of the xfer switch.

In hindsight, I shoulda checked it anyway! 

 

Thanks again for the help, and I hope this thread helps someone else out down the road.

 

[wildebill308]

Thanks for checking back with us with your results.

Bill

[dickandlois]

There are a few items that can cause the AC units to draw a higher current. 

       1. Low line voltage / but running on the generator - if yours is large enough should answer that question if you do not have a way to measure the incoming line voltage.

        2. The evaporator unit is dirty or has been damaged in some way. The AC compressor current increases as the temperature increases because increased temps causes the compressor to work harder as the pressure in the system increases.  

         3. Loose electrical connections or damaged wiring can cause the AC compressor to work harder due to higher resistance in the wiring that reduces the voltage at the compressor.

         4. A slow running fan motor - caused by dry or defective bearing, or a damaged fan blade that reduce air flow through the evaporator.

 

Rich.