AC Troubles - Hard Start cap? Something else?

...and I think I mis-identified some of the parts, and I believe this to be accurate now:

1) Does the Tall Gray one, have two clusters of terminals, with a divider between like the Short Gray one? If so, Tall Gray is your Compressor Run Capacitor. The uF value sounds high, and when I say that, I'm working from recall, not a parts list.

1) EDIT - I must've looked at the same parts list and other sources you did, and 60 uF for Compressor and 7.5 uF for Fan seems to be correct. If you're looking to test capacitors by substituting "known good" (presumably new) caps, you can get such from appliance repair parts shops as well as eBay and Amazon. I've noticed your A/C series uses a Panasonic Compressor. It may be different enough from others, to call for a different uF capacitor.

2) The Short Gray one is the Fan Run Capacitor, and the 7.5 uF you mentioned sounds about right.

2) EDIT - 7.5 IS right

3) Start Assist Capacitor is used only with Compressor. You should find it connects across the Tall Gray one - Those Start Cap's are almost always plastic. Most of the A/C's I've tinkered with do not have Start Assist, so I'm not sure about testing them. I believe some of them have a small resistor across, and not sure that would allow testing with a meter.

Have you tried your generators with a good parallel kit yet? You may be doing all this for nothing.

Alright. Update. Got my new parallel cable and generators are running good. Tried the AC right off the bat and got it to run. I was really grinning at this point but I knew that the real test would be cycling the compressor. I switched the AC off then back on, waited the required time, listened to the compressor come back on and... Overload.

I gradually started turning various other 110 loads off and trying again and again and again and I never could get it to fire. At one point, I have the converter, fridge, and any other 110 loads I could think of and it would still kick out.

At this point I decided to check the caps. Fan run cap tested low, but within 10% of nominal (7.0 uF actual vs 7.5 nominal). Compressor run capacitor also tested low, but within 10% of nominal (56.4 uF actual vs 60 nominal).

Compressor start capacitor, well, not so good. I will try to get pictures later tonight but it had a nominal value on the side of (47-56 MFD). I'm going to assume that is milli Farad? Or is that also micro? I tested it at 51 uF, so it kinda matters which one because it's either dead on or way off. The part number on it is 1497-090.

I will try to get pictures.

Edited to add - the start capacitor had a resistor across the terminals. I un-soldered it before taking these readings. Neither of the other two caps had resistors.

Alright here are pictures.

Uh oh, a google search reveals its supposed to be microfarads, in which case that cap is testing fine, too. Shame, I was hoping that was the smoking gun.

The $300 for a Micro-air is starting to look better all the time.

What else can I do? What else could be causing this?

I see the new Coleman hard start cap and PTCR kits are like 108 uF (double what I currently have) . Would a larger cap help or am I grasping?

I tested the existing PTCR for continuity and it came up good. It's supposed to, right?

Here, on RV.net, the "start kit" debate centers around SUPCO SPP6a and SPP6e. The 6 is a PTCR unit, and the 6e uses an electronic sensing circuit. SUPCO recommends the 6. Doug, mentioned earlier, is one of our frequent RV Tech members. Chris Bryant is another, and Chris uses SPP6e. Both are not equivalent to the Micro Air. SUPCO says SPP6 with PTCR allows the generator a little more time to spool up in response to the compressor load, and SPP6e will drop out prematurely. Chris sticks by his SPP6e recommedation. I'll never have a capacitor failure, because I have spare Fan Run, Compressor Run, and Compressor Start Assist on board. My backup unit is SPP6e...

I don't have a dog in the Generator Hunt. I don't know why it is, but it seems from casual observation that Honda 2000's do the best job of starting A/C units. I don't think it means they have better overall capacity, and can only guess that their circuitry just keeps them from giving up quite as quickly as others.

SPP6e is $22 on Amazon, SPP6 is under $10. So what have you got to lose?

There's a recent thread about Micro-Air, and it sure seems that one of those would solve the start problem. Find that thread, Micro Air Results, and see what they say. Here it is. I don't want to add searching to your frustrations.

LipschitzWrath wrote:
Uh oh, a google search reveals its supposed to be microfarads, in which case that cap is testing fine, too. Shame, I was hoping that was the smoking gun.

The $300 for a Micro-air is starting to look better all the time.

What else can I do? What else could be causing this?

I see the new Coleman hard start cap and PTCR kits are like 108 uF (double what I currently have) . Would a larger cap help or am I grasping?

I tested the existing PTCR for continuity and it came up good. It's supposed to, right?

So your suggestion then is to start looking into supplemental starter technology? There's nothing wrong with my setup?

On my home A/C the compressor start capacitor is usually the one the goes bad most often. I'm on my 3rd one since my new A/C was installed in 2012.
I keep an extra around for easy replacement.
Often the A/C will continue to work while the capacitor is starting to go bad, but the amps drawn when the compressor starts will start to increase.
I usually rely on swapping to a new capacitor as this actually "tests" the capacitor under operating conditions vs testing with a DMM with a capacitor function.

Testing Start Capacitors
http://inspectapedia.com/electric/Motor_Capacitor_Tests.php

If you swapped in a new start cap like a Packard 330V Start Capacitor 53-64 MFD going for about $10, and still having trouble with starting the A/C on the generator, then the soft start might have to be the answer.

Also an AC/DC ammeter like Elenco ST-3030 AC/DC Clamp-on Ammeter is great for seeing amps being used by the A/C (startup, running) as well as DC amps in the 12V system.


Hard Start Kits:
http://www.achrnews.com/articles/120282-mismatched-kits-cause-failures
http://www.achrnews.com/articles/89314-hard-start-devices-insurance-for-the-compressor

Gene

gbkim wrote:
On my home A/C the compressor start capacitor is usually the one the goes bad most often. I'm on my 3rd one since my new A/C was installed in 2012.
I keep an extra around for easy replacement.
Often the A/C will continue to work while the capacitor is starting to go bad, but the amps drawn when the compressor starts will start to increase.
I usually rely on swapping to a new capacitor as this actually "tests" the capacitor under operating conditions vs testing with a DMM with a capacitor function.

Testing Start Capacitors
http://inspectapedia.com/electric/Motor_Capacitor_Tests.php

If you swapped in a new start cap like a Packard 330V Start Capacitor 53-64 MFD going for about $10, and still having trouble with starting the A/C on the generator, then the soft start might have to be the answer.

Also an AC/DC ammeter like Elenco ST-3030 AC/DC Clamp-on Ammeter is great for seeing amps being used by the A/C (startup, running) as well as DC amps in the 12V system.


Hard Start Kits:
http://www.achrnews.com/articles/120282-mismatched-kits-cause-failures
http://www.achrnews.com/articles/89314-hard-start-devices-insurance-for-the-compressor

Gene

Thanks for the info. By following these instructions, the capacitor continues to test good. Should I replace it anyways?


If so, and like I said, the new Coleman hard start kits have a larger start capacitor. Are there advantages/disadvantages to using a larger cap?

If you decide on the Microair easy 364 at $299...type in airstream into the discount code, $40 off.....now $259

marcsbigfoot20b27 wrote:
If you decide on the Microair easy 364 at $299...type in airstream into the discount code, $40 off.....now $259

Thanks very much! I'm kinda leaning that way. A new hard start cap kit from Coleman is 20-30 bucks. Coupled with the discount code you graciously gave me, we're getting a lot closer to $200. Since it replaces the start cap, I'm thinking it may just be a better idea to go that way.