Actron tripping 40A Breaker

[Keza]

Hi everyone,

Just after people's thoughts on an Actron ducted fault.
Model:SRA17C single phase with soft starter.
Ok so the customer called and said the A/C has tripped the breaker and continues to do so (40A) single phase. Worked fine for 9 years.
First I tested comp and fans for grounding, they were all clear.
Tested all capacitors, found one 50mf gone which was the run cap so i replaced that.
Start Cap tested wierd tho, supposed to be 100-120 but was around 300 wierd.
Turned unit on cooling, both condenser fans came on at high speed.
Compressor soft starter PCB has 3 min delay so I waited, and waited and waited.
No compressor not even a shudder, just a few clicks and clacks from the PCB.
I checked for power to the soft start PCB at "REQ" terminal which comes from the main PCB terminal "Comp" (which i assume is a request for compressor to start) it had 240v.
So the unit is calling for cooling but the compressor won't come on.

I think it is the soft start PCB with the issue. Interesting to hear what anyone else has to say.

Thanks guys

[HVACRsaurus]

Would you have a megger?

Suggest removing wires from compressor & megger windings to earth.

[Keza]

Hi Hvacasaurus,

Yeah mate as i said I have checked fans and comp for grounding, they are all clear.
Everything runs except compressor, and didn't trip breaker while I was there.
That's why I'm suspecting it had a faulty soft start PCB which caused the breaker to trip and now it's completley faulty and not bringing on the Comp.

Cheers

[Airsteve]

Hi Keza
As mentioned above you need to do an IR test on the compressor. If it is ok inext step would tbe to replace the start cap. You have already proven it is incorrect, dont second guess yourself. Next wire the compressor DOL bypassing the soft start to prove the compressor is not seized or has not put stress on the soft start causing its failure.

[Keza]

Thanks Airstreave,

Yep I have IR tested the comp its fine. What I think is wierd is the compressor didn't even try to start or humm,if the start cap was faulty it would humm and trip the breaker most likely. I will have to try DOL when I go back with the soft start PCB. Anyone know how to bypass soft starter? I've only done it a few times and not that familiar with doing it.

[HVACRsaurus]

Cheers.

Just thinking out loud, the kinds of things to draw excess current

Short to earth - checked
Short to neutral - peniding "start"
Locked rotor - again pending start

Maybe a bump DOL like Airsteve mentions is worth a try!

[Keza]

IMG_3435.jpg

Could anyone advise how to DOL, this is the wiring diagram

Thanks

[Airsteve]

I am not famailar with your exact unit however most units with a soft start apply power to the common from a contactor or relay then control the start and run circuits throught the soft start. Confirm this before follwing the next step. Power/active from a contactor to the compressor terminal common, run terminal to neutral, start terminal with a wire to one side of your new start cap, the other side of start cap to neutral. Make sure your nuetral wires are good. Remeber they carry the same current as the power supply wires. I have left many unts running like this until i return with a soft start module.

[Airsteve]

Ok just seen your pic. Forget what i just said. Compressor common is neutral. Apply power to run terminal and start cap from contactor, other side of cap wire to compressor start terminal.

[HVACRsaurus]

Just as Airsteve - Good one!

[Keza]

Thanks heaps Airsteave you know your stuff. So let me clear it up.
Because there is no contactor I can bridge out terminals "Run" and "ACT" to put power to run terminal but if the soft start PCB is faulty the run cap is left out. There is a start cap that's not in the wiring diagram ( it is wired to the soft start PCB) sorry I'm still confused

[Keza]

Just saw your last post give me a minute to read it sorry disregard my last post

[Keza]

Haha holy hell, I don't know if I'm keen on doing that if the comp is locked rotor/shorted my eyes might get welded shut. I wonder if there's another way to do it. Looks like I'm going to have to go out with a new start cap and soft start PCB, then amp test.

[HVACRsaurus]

go out with a new start cap and soft start PCB, then amp test.

Hear, hear

[Airsteve]

If you fit a new soft start and the comp is seized you might cook the new soft start. Best to wire the way i said through a contactor using whatever turns on the soft start now turns on your contactor A1. Your pic is a little blurry at my end. Cant help much more with wiring configuration.You can leave the start cap connected & running off the contactor the whole time the compresor runs, theres no need to drop it out, you wont hurt it. Its not a current start relay. Just make sure you tong it when it is up and runnin. You can always fit an in line fuse or breaker to the power you are putting into the compressor. My moneys on the soft start just simply being faulty.

[Magoo]

Had similar problem with Temperzone/Bradway large single phase issues with caps etc., isolated compressor and everything clear . New soft start all went fine after that, unit location at risk of voltage variations so recommended to client spike and voltage sag protection.

[Keza]

Ok guys thanks for the input, I'll let you know how I go, hopefully the comp ain't siezed!

[Keza]

So what I will try Airsteave is:
Fit a contactor, use "REQ" terminal as A1 to contactor. From load side if contactor put power to one side of start cap and from other side to start winding. Also from load side of contactor power to one side of run cap and from the other to the run winding? Am I on the right track?

[Airsteve]

So what I will try Airsteave is:
Fit a contactor, use "REQ" terminal as A1 to contactor. From load side if contactor put power to one side of start cap and from other side to start winding. Also from load side of contactor power to one side of run cap and from the other to the run winding? Am I on the right track?

Fit a contactor, A1 would most likely use Comp terminal from pcb to bring in contactor which brings in power to compressor. Again diagram is a little blurry. Disconnect all wiring to soft start. Mark it off as you will most likely be reinstating it later. From load side of contactor 1 wire straight to run terminal of comp. No need for the run cap, leave it out/disconnected. Another wire from contactor to one side of start cap, other side of start cap to start terminal. Just think of it as a normal capacitor start induction run set up. No different to many other compressors you would have seen. The only difference being power is going in to start and run windings instead of going in to common. Don't forget to tong it to make sure it is happy.

[Magoo]

So as a mind bending question, what is Actrol tech support saying. Playing around with what ever options will null invoid any warrantys, the out clause. A good bunch to talk to irrespective of out come

[Keza]

Thanks very much Airsteave! Will try that before I fit new soft start PCB.
Hi Magoo, I called Actron tech support and told them what I have found and tested and they suggested to replace the soft start PCB and Capacitor. Warranty isn't an issue as it 9 years old

[Nudge]

On a unit with 40 amp breaker it only takes a loose or hot connection
on your pole or switch board all the way to your compressor or bad
contact to draw LRA. Which will cause tripping.

[Grizzly]

On a unit with 40 amp breaker it only takes a loose or hot connection
on your pole or switch board all the way to your compressor or bad
contact to draw LRA. Which will cause tripping.

Or Just old and Tired equipment?
Grizzly

[Keza]

Hi guys,

Just updating everyone. The problem ended up being a faulty soft starter PCB. The new soft start module came with the start cap built in. Thanks everyone for the help!