Hard Start Capacitor install issues

[drumming102]

Hey guys,

I have a dometic AC unit on my Passport 2920BH. It's like a polar ice 2 or something like that (13.5). It also has a 5-6 sec delay compressor start after fan.

I purchased a Supco SPP6 https://www.amazon.com/gp/product/B008FM8X3Q to install on the run Capacitor.

When I cracked open the electrical box I found only 1 capacitor instead of an expected 2. Are they combined? The wiring diagram almost makes it look like they are.



Well I hooked up the relay side (with the extra prong) of the SPP6 to the red wire post and the other to the white (As per the schematic) and it seems like my genny takes an even bigger hit when it starts and stumbles more. Is my cap bad? AM I reading the diagram wrong?





I even tried reversing the SPP6 wires

"Help me RV.net forums, you're my only hope"

Genny is a 3100 Champion inverter. It runs the AC but just trying to make the start a little easier on it.

[PaulJ2]

Wire diagram shows that you already have a cap in the starting winding circuit "usually about a 40 mfd". Adding another in parallel would not work with double the capacitance. You need to go with the "optional" boost system or the original, not both.

[ksg5000]

Years ago when I installed my Supco I called them on the phone and provided them with photo's similar to the ones you have provided - they walked me through the install. Nice people who provided great service. Might try giving them a call.

[SoundGuy]

Several years ago I installed an SPP6 on my 13.5K Dometic A/C which has just one stock cap, connected to where the white & red wires connect ... seems to work fine. However, if I were to do this again I'd instead install a Micro-Air Easy Start soft start kit which would really improve compressor start up. My SPP6 pics are here if it helps any.

[pianotuna]

Hi,

The Microair Easy Start will accomplish what you want for $318.00 USD.

A mini split air conditioner would be super, but you had better have very deep pockets.

1320Fastback wrote:
Watching with interest. Did the same mod and if anything made starting harder.

Honestly considering getting a high efficiency A.C. to replace the factory one.

[1320Fastback]

Watching with interest. Did the same mod and if anything made starting harder.

Honestly considering getting a high efficiency A.C. to replace the factory one.

[wa8yxm]

There are indeed two capicators.. Just they stuffed 'em both in the same can.

YOu will simply disconnect one of them.. I THINK but am not sure there is a lead common to both, but that connection is made externally. not internally. It is not uncommon for a single can to have 2,3 or more capacitors in it.

[ScottG]

I just replaced a cap like the one shown in your schematic for my residential AC. It is a dual capacitor with two different value caps inside. You can either use another dual cap or two separate and properly rated caps.
You cannot replace the dual with a single because the values are different.

[drumming102]

MrWizard wrote:
the schematic drawing
shows 4 whites, 2 reds, 1 brn

from what i can see in the picture, you don't have enough wires for it to be pre-installed

dometic charges big bucks for an a/c unit, then skimps and never puts in the additional hardware for better starting

Yea. Im sure one is not installed.

[MrWizard]

the schematic drawing
shows 4 whites, 2 reds, 1 brn

from what i can see in the picture, you don't have enough wires for it to be pre-installed

dometic charges big bucks for an a/c unit, then skimps and never puts in the additional hardware for better starting

[drumming102]

j-d wrote:
I wonder if that "spooling up" remark is valid for both the constant speed and the inverter generators...

I noticed the pics you posted show the SPP6 label different from the SUPCO site.

From what I've heard, the compressor can't start if the start assist capacitor fails to get out of the circuit. So your idea of a bad SPP6 might have something going for it.

Not sure if I just wanna try another SPP6 or grab a SPP6e for 9 dollars more and prob make sure I dont get Old stock.

[j-d]

I wonder if that "spooling up" remark is valid for both the constant speed and the inverter generators...

I noticed the pics you posted show the SPP6 label different from the SUPCO site.

From what I've heard, the compressor can't start if the start assist capacitor fails to get out of the circuit. So your idea of a bad SPP6 might have something going for it.

[j-d]

There's debate over the best "hard start kit." Not talking "soft start" like Micro Air that's much more effective and much more expensive.

Basic Hard Start is Capacitor and PTCR like SPP6.

Then there's Electronic that's a little smarter like SPP6e.

Better is a "Potential Relay" that does a better job of determining compressor's starting status.

Our gurus here think the "e" series does a better job than PTCR, but SUPCO defends PTCR. They claim it gives the generator more time to spool up and help start the compressor.

[drumming102]

j-d wrote:
From the diagram and the pictures, you have a two-in-one Run Capacitor. The Compressor runs on HERM and COMMON. Chances are only HERM (Compressor) and FAN are marked, and COM is the third one.
The SPP6 has two wires that go to HERM and COM. Doesn't matter which is which. The SPP6 contains a Start Capacitor and a Positive Temperature Coefficient Resistor (PTCR) to take it out of circuit when it thinks the compressor is up to speed.

You diagram shows the equivalent starting device labeled "Comp Start Assist" with its Red and White wires going to HERM and COM on the two-in-one RUN capacitor.

IF IF IF the Comp Start Assist was an option and it's NOT already there, then you can add SPP6. If it's already there, DO NOT add SPP6 as a second one.

Yea there is NO other cap installed. the diagram just helps you with installing one like this if you want. My SPP6 must be junk then.

[drumming102]

lawrosa wrote:
Cant tell the model off amazon you got......

but you need a Positive Temperature Coefficient Relay model..Thats per your schematic..

Can you verify?
http://www.supco.com/web/supco_live/products/SPP6.html

This is exactly what I have i believe. Mine MIGHT be old stock though as it looks like the label is a bit diffrent.