AC Troubles - Hard Start cap? Something else?

[LipschitzWrath]

Okay guys, new member, long time lurker.

The missus and I finally bought ourselves a 5er, a 2004 Terry Quantum Ax6. It's huge and we have had it out a couple times. Got a great deal on it and we love it.

Lately it's been getting hot enough that we want to use the AC and that's where the problems began. I am running two brand new Yamaha Ef2000isv2 generators in parallel (kinda), so I feel like I have enough juice. Other relevant details is I'm at 6500 feet elevation and the air condonitioning unit is a Coleman Mach 15k unit. My research indicates it has the factory start capacitor kit installed. Full model number is 8335b6764.

First let's clear up the generator thing. It appears I have a bad parallel cable that yamaha is doing a warranty on. The pins inside the cable broke off and I'm not sure I ever had true parallel capability. Maybe I did but everything I've been told is these generators shouldn't struggle at all to start this ac and I've been successful I think 2 out of 25 times.

Ideas? Could the factory capacitor be bad? Would adding an aftermarket (say spp6) cap help at all or is the factory set up about as good as you can do?

Do I need to get my refrigerant levels checked?

[LipschitzWrath]

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?

[gbkim]

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

[LipschitzWrath]

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?

[j-d]

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]

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?

[LipschitzWrath]

Alright here are pictures.

[LipschitzWrath]

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.

[j-d]

...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.

[LipschitzWrath]

Looking back through my pictures, it looks like I have 3 capacitors.

1) Tall grey one in back left (closeup reaveals 58uF, part number search 1499-576 says 60uF and lists as "Fan Capacitor")
2) Short grey one in front (closeup not clear, part number search 1499-546 says 7.5 uF and lists as "Fan Capacitor")
3) Short black one in back right, next to #1 above (no closeup, no part number)

I'm pretty sure #3 is the start capacitor as the PTCR sits above it. But what are #1 and #2?

[LipschitzWrath]

Furthermore, am I correct to assume that when testing the start capacitor, it needs to be tested without the PTCR in the circuit?

[LipschitzWrath]

j-d wrote:
You can replace your combination capacitor with two separate ones with the right rating. You need a Jumper to connect one terminal of each to one terminal of the other, forming a "Common"

Is this advisable? Are there advantages?

How do I go about sourcing parts? Are there OEM parts available?

When you say "separate ones with the right rating", how is the right rating determined? From what you are describing, it sounds like they need to be wired in parallel and my understanding is that caps in parallel sum their capacitance. So how do I determine what each cap needs to be for the fan and compressor?

[j-d]

To test Capacitors with a Meter that shows "Capacitance" "MicroFarads" or "uF"...

Shut Power OFF.

Short across Capacitor(s) with an insulated tool like plastic handle screwdriver.

Disconnect Capacitor from Circuit

Apply Meter Leads

Should read out within about 10-pct of the rating on the capacitor label

Pix look better! I can now see that you have

Combination RUN Capacitor supporting Fan and Compressor with separate sections

A Start Assist Capacitor

A Start Capacitor Relay

You can replace your combination capacitor with two separate ones with the right rating. You need a Jumper to connect one terminal of each to one terminal of the other, forming a "Common"

You capacitors may be labeled 370-volts-AC and new ones are usually labeled 440-volts-AC. That's fine.

[LipschitzWrath]

j-d wrote:
You have a 15000 A/C from Recreational Vehicle Products. That's the Coleman brand, and most of those have start assist. InThis Thread, see dougrainer's post. It confirms that your Model Number was built with Start Assist.

I'm glad you posted model number and pix, but your huge pix are giving me a headache. Very hard to get the overall view of the capacitor area. It seems there's a Run Capacitor for Fan and for Compressor, plus a Compressor Start Assist Capacitor and what I think looks like a Potential Relay. If so, that setup is about as good as it gets till you go to a Micro Air unit.

I completely agree. Coleman Mach 8335 15k BTU AC unit. The model number decoder said it came with a factory start capacitor kit, which I confirmed when I opened it up.

j-d wrote:
The appearance of the capacitor area of your unit, from the pix, makes me think it's far from a new/late model A/C. That opens the possibility of a failed capacitor(s).

The camper was built in 2004. The appearance certainly suggests the unit is original. The previous owner didn't mention that any work had been done to the AC, but I didn't ask specifically either. I never thought about the failed capacitor possibility. Can they be tested? I *THINK* my nicer multimeter I own can test capacitors. Is it as simple as testing across the terminals? Do the wires need to be disconnected? Any insight would be appreciated.

j-d wrote:
But... ONE 2kW genny is NOT gonna start a 15000, Start Assist or none. Micro Air? Maybe, but I admit that issue is above my pay grade.

My guess? A good parallel arrangement will get you going. If not, check capacitors.

Agreed. I was never foolish enough to think one 2kW genny would do it. From the very beginning I bought 2x EF2000isv2 generators with parallel cable. Thus is the basis of my dilemma. If the parallel cable was in fact the issue, then my problem may be solved. I finally got the local Yami dealer to agree to warranty the cable and am told that I should be able to pick up the new one tonight. I should be able to test tonight to confirm if the generators will start it.

j-d wrote:
And, NO "extension cords!" An RV extension cable, OK, but you're better to plug your coach right into your parallel genny's.

Please re-size your pix.

I have to do it via the genny's as I do not have a 30A shore service to plug my 5er into at home. I have it plugged into a standard 15A service to essentially keep the batteries charged but know that there is no way it's going to run something like the AC or the microwave.

I think I resized the pictures, let me know if they are still a problem.

[j-d]

Welcome aboard!

Let me try to help.

You have a 15000 A/C from Recreational Vehicle Products. That's the Coleman brand, and most of those have start assist. InThis Thread, see dougrainer's post. It confirms that your Model Number was built with Start Assist.

I'm glad you posted model number and pix, but your huge pix are giving me a headache. Very hard to get the overall view of the capacitor area. It seems there's a Run Capacitor for Fan and for Compressor, plus a Compressor Start Assist Capacitor and what I think looks like a Potential Relay. If so, that setup is about as good as it gets till you go to a Micro Air unit.

The appearance of the capacitor area of your unit, from the pix, makes me think it's far from a new/late model A/C. That opens the possibility of a failed capacitor(s).

But... ONE 2kW genny is NOT gonna start a 15000, Start Assist or none. Micro Air? Maybe, but I admit that issue is above my pay grade.

My guess? A good parallel arrangement will get you going. If not, check capacitors.

And, NO "extension cords!" An RV extension cable, OK, but you're better to plug your coach right into your parallel genny's.

Please re-size your pix.

[1320Fastback]

True, or im ulucky and always plug it in the same.

These gens are somewhat easy to take apart and I plan to look at the wiring connections soon. When we got them (inherited) they were new but had stale gas in the carbs and i tore them down to clean them out. Will pull apart and check the wiring maybe this weekend.

Also plan to build my own parallel cable and see what that does.