Soft Start Install Issues

[Mdk0420]

Hey all. Been having issues with my generator not starting my AC which is in another post. One of the solutions I was going to try is a soft start but now I am having issues there as well.

I have a 2003 Sunline with a 13.5k btu Dometic 59516.331 AC. I shouldn't have an issue starting this AC with my 4.5kW generator but I was hoping a soft start would help. If you want to know more details about the AC issue it is here: https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30394124.cfm

So I am trying to install this soft start and I think I might have it done correctly but I am getting a "Stall" error on the soft starter. When I tried to pre load the system with the microwave running, I got an overload error.

I bought the Micro-Air 364 X20 model. My AC is 120v so I figured this should be fine. I tried to follow the install instructions but I am having a few questionable connections when trying to follow it.

My system has its main capacitor, a motor start winding connection (I think this is the "Disc" that the install instructions mention) and the motor starter capacitor. It says that I can get rid of the motor start disc and I assume that includes the motor start capacitor as well since the way the install instructions read sounds like that is the case.

Connecting the orange wire is simple, just plug it into the HERM connection on the capacitor.

The Brown, White and Black wires need to be connected to the "Contactor" I looked everywhere for this contactor. What is pictured doesn't seem to exist in my system. However I believe the terminals on top of the compressor might be the contactor? The manual says to trace the "C" wire to the contactor. There are only 3 white wires remaining after removing the motor starter components. One goes to the fan, one to the terminals on top of the compress, and one that goes into the camper and connected to the romex wire that brings the power to the AC unit.

So that's why I assume the terminals on top of the compressor is the contactor. Is this correct? Because all of my wiring continues from here.

It is labled S (W) for the red wire, R for the white wire, and C for the black wire. I removed the R wire and connected the brown wire from the soft starter to the wire itself that I just removed. I then connected the white wire from the soft starter to the R connection on top of the compress. Finally I removed the red wire, used the provided double pin adapter to connect the black wire and the red wire to the S terminal.

The other black wire has a very small run to another piece on the compressor. I think this might be some kind of overload protection. It is a little circle that has the black wire connected to it, then the other terminal has a blue wire that runs back inside the camper and makes a connection to the little circuit board in there that is labeled (NO). The other terminal on that block is labeled "COM". This COM wire is the hot side of the romex as it has a wire nut that makes that connection.

When I start the system up in this configuration I get the huge draw of power, I hear the compressor starts humming but maybe 2 seconds later it cuts off and I get that "Stall" error.

A key thing to note is that I do not have any good AC power to start off with. The line I had it plugged into my garage is a whopping 250' of 14/2 wire. The voltage drop can hardly start power tools let alone a large surge like an AC (My portable 15k unit cannot start with the outlets).

I tried my generator too but the same thing happened. So I may be experiencing too high of a voltage drop. However I thought the point of a soft starter was to slow down this surge so it didn't have such a huge rush of power, hopefully drawing closer to 20amp on startup instead of the 48amps I get when my generator trips.

It got late while trying to install this so I did not do any voltage drop tests or amp draw tests. The generator never tripped when trying to run it. But the soft starter tripped now with those errors.

If you are familiar with these systems please let me know any suggestions. Especially if I missed some kind of wiring step that might be messing up the compressor starting up. On the install instructions it says to run it at least 5 times on AC main power before running off a generator to have it "Learn". I think this weekend I'll hook my camper up and bring it out front to get it more reliable power to test it. In the mean time I just want to make sure I got everything done correctly because now the AC 100% doesn't work on the generator while before I could start it about 90% of the time with it tripping every once in a while while running or if I short cycled it I could cause it to trip as well.

[pianotuna]

Mdk0420 wrote:
Soft start issue solved (along with the AC issues). It was indeed the wiring issue.

Great that you got it fixed! Well Done.

[Mdk0420]

Soft start issue solved (along with the AC issues). It was indeed the wiring issue.

[Mdk0420]

pianotuna wrote:
Mdk0420 I preferred my autoformer to the MicroAir.

I could reliably start the 13500 btu Dometic on my Yamaha Sieb inverter generator. It does have 500 watts of extra boost.

I went off of a recommendation from another user here. Seems like a pretty solid soft starter. Hopefully it works great since it was over $300 :X but if it solves my issue that is better than a new AC unit lol

[Mdk0420]

bgum wrote:
Micro air soft start claims to provide excellent help via phone so why are you guessing about how to install. Call them as you are clearly confused.

I submitted a question to them via their website. I was able to find the correct installation for my specific unit after some research though.

They still did not get back to me but it is the weekend after all, however I need this figured out this weekend as I leave Thursday and won't have much time doing the weekday to solve the issue.

[Mdk0420]

Galvanizd wrote:
Did you get your ac to operate properly on shore power? From your other post, you were having problems with the generator tripping. Might want to get your ac operating properly before installing your soft start.

That would include re installing your 12 volt battery to your rv. The ac will not work properly unless both shore power AND the 12 volt battery are connected. Can't imagine the the soft start will work any better until the ac unit is working properly

I'll be checking some things tomorrow. The generator can start it about 90% of the time. Ac shore power always starts it the problem is I don't have good AC power st my garage because of a bad wiring job. The AC was fine anytime I was plugged into a camping spots AC though.

The issue is the huge surge that my generator is seeing. I'm still not entirely sure if it's the generator or the AC having issues but all the details are in that post about what I've been test8ng.

The hope is that the soft start will lessen the surge draw so my generator can start it. From what the one person was saying it seems that dometic just has high drawing ACs. His one post showed a 37amp draw. I get 28-30amp draw when successful but a 48amp draw when it fails.

[Galvanizd]

Did you get your ac to operate properly on shore power? From your other post, you were having problems with the generator tripping. Might want to get your ac operating properly before installing your soft start.

That would include re installing your 12 volt battery to your rv. The ac will not work properly unless both shore power AND the 12 volt battery are connected. Can't imagine the the soft start will work any better until the ac unit is working properly

[pianotuna]

dalej wrote:

pianotuna wrote:
Mdk0420 I preferred my autoformer to the MicroAir.

I could reliably start the 13500 btu Dometic on my Yamaha Sieb inverter generator. It does have 500 watts of extra boost.

Would you share which autoformer you used.
TIA

It is in my signature.

Sola Basic Autoformer 4000 VA So about perfect for a 30 amp RV. They do have 50 amp autoformers as well--but you would need one for each leg to get the full monty.

[dalej]

pianotuna wrote:
Mdk0420 I preferred my autoformer to the MicroAir.

I could reliably start the 13500 btu Dometic on my Yamaha Sieb inverter generator. It does have 500 watts of extra boost.

Would you share which autoformer you used.
TIA

[bgum]

Micro air soft start claims to provide excellent help via phone so why are you guessing about how to install. Call them as you are clearly confused.

[Mdk0420]

Well I feel really silly. After looking at my image some more I was so baffled at have double connection to the (S) terminal on the compressor. I looked up some manuals from Micro-Airs website and long and behold...

https://pasteboard.co/muahNFRxR0uK.jpg

Guess that solves my soft start issues. They have is much different than the manual they sent me though with the wire splicing and such. It seemed like a manual that tried to explain different types of AC units so I thought it was their all in one manual. But this photo of their wiring diagram specifically for the dometic duo therm series shows its different.

Orange wire still went into HERM so thats good. I think their "Blue" line is their white wire (I used grey lol). This seems to be functionally the same, however its backwards and I wonder if that would cause any issues... Essentially my brown wire is connected to a common terminal of the capacitor while my white wire is connected to RUN. This diagram shows brown wire connected to run and white wire connected to common. I will reverse my installation just incase lol.

And last but certainly not least, the black wire was definitely wrong. When I noticed I had 2 wires on S that just didn't seem right to me. Crazy enough, I actually did tie into the black wire originally but I did that AFTER the O/L protection, this shows to do it before. I'm wondering if that is a normally open circuit so it never gets power after the O/L which is why I didn't get the power I needed when connecting the two black wires... I will splice it the way they are showing it here because I think that might be the case.

It doesn't seem like this should damage anything though from what I'm looking at... So hopefully I didn't damage anything lol. Just looks like I ran a double capacitor on the S cycle and nothing on the R cycle so it wasn't able to keep going and tripped.

I bought it on amazon so there was no selections for the model I was installing it on or anything. I guess I just got a generic soft start installation manual. Shame on me for not looking into a more specific manual. But maybe someone else could use this in the future when googling "Micro Air Soft Start Not Working On Dometic AC Unit" lol

[pianotuna]

Mdk0420 I preferred my autoformer to the MicroAir.

I could reliably start the 13500 btu Dometic on my Yamaha Sieb inverter generator. It does have 500 watts of extra boost.

[Mdk0420]

I found the instruction manual for this setup. Still don't see a "Contactor" like the instructions mention so I am feeling a little more positive that the terminals on top of the compressor is the contactor. Here is how I have everything wired up now



Image wasn't loading for me so here is the link instead. Hope this is allowed:

https://pasteboard.co/z8R9C0WkOh8d.jpg

Moderator edit to fix image for posting.