hard-start kit for A/C (helps smaller generators work)

[rickst29]

CORRECTED IN AUGUST, 2020

In other Threads, some people have looked at the 58-amp power requirement for the Polar Mach 9203 A/C start-up and said, "that's impossible, I don't believe it". But the figure is correct for the motor with fan and compressor attached -- you didn't remember that they've got a fairly big "run" capacitor in there to help it along, for higher efficiency, and that capacitor also provides substantial help during start-up. (It's either 40 or 45 Mfd@370v, depending on whether your model year has the Sanyo or Tecumseh compressor). There is a separate 7.5Mfd capacitor for fan start assistance, but most of the improvement is provided by the bigger "compressor run capacitor". Polar Mach 9203 is not built with a compressor start capacitor, because they cost money and plugged-in people all have 30 amps available, don't need 'em.

That's what these "hard start kits" add back in. When needed, the "run" and "start" capacitors only assists for small fraction of a second, but the power draw of the motor and compressor also go down rapidly as they begin to move. And so, the maximum draw from the 30A plugin (to shore power or Generator) is quite a bit less than the 58A figure. Exactly how much less, I don't know (and I'm not going to move and open up the Trailer just to measure it). But from what I've been reading, I'll SWAG that's right around 26 amps.

This can be improved, enormously, by adding on a hard-start kit. I've just poked around the Internet a bit, and finding a few posts like this one, raving about this particular product in use with Coleman-Mach 9203 3500-BTU units, so it seems to be the right one to get. (NOTE: he typo-ed the model name, it's actually "Supco SPP6".) BTW, efficiency would go down, a lot if you merely replaced the current run capacitors with bigger ones. The monitor and timing circuits within the "head" of this hard start kit prevent it from creating mismatched capacity during regular "run" time. That's why you buy the kit, instead of just a wrongly-sized "run capacitor". BTW: For the standard Coleman-Mach A/C on most TM (roof air conditioner), the slightly more expensive Supco SPP6E"e" would be a mistake, the discharge timings end up wrong.

After removing the A/C shroud, it's a 10-second job: just clamp the leads right in parallel with the existing "run" capacitor.
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Now, some of you might want to ask if this would let you run our A/C units with a mere "2000 watt" generator after installing this. Well, in Desert temps, and late July in the Central valley, the continuous draw from the 9203 gets up to about 14 amps. The "2000 watt" Honda and Yamaha models offer 16.7 amps peak, but only 13.3 amps continuous rated power. So, although the hard-start kit probably WOULD allow you to start, it's a really bad idea: it's just too much load for one of those little guys. Those "2000 watt" generators are really "1600 watt" generators with 200-watt peak output. I'm recommend against this kind of generator overload abuse even at sea level, in lower temps.

I won't need one if I proceed to buy dual, interconnected "2000 watt" Yamaha or Honda generators for running A/C -- even in Desert heat at high altitude, A/C start should be a piece of cake for the "4000 watt" combination. But for owners of the Yamaha 2400is and units of similar size, this is the ticket to assuring safe A/C start in high altitude/high heat conditions. (Which reduce your generator's output at the exact same time they're increasing the A/C electrical requirements). I'm pretty sure that this $30 add-on will help get you "over the bar" in all such circumstances.

typical pricing on the web is about $20, plus $8-10 shipping. (Directly from Supco, it is available about $35.)
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NOTE ON CORRECTION: Corrections were provided to me by our member RejoiceWay who emailed to Suppco (to verify the correct model for TM Air Conditioners). (Thanks !!!) From Technical Support representative Michael DelMauro, he received the following:

The current Trailmanor air conditioner is 120 volt 9000 BTU. RVP is the manufacturer with model #9203c876. I went to the web and looked at the specifications for the Supco SP66E units and saw it was for units above 170 volts. I followed up with an email to Supco to check on using this unit on our air conditioner. MIke DelMauro responded with the following " The SPP6 would be the proper match. The SPP6E is designed for higher voltage applications.

https://www.supco.com/web/supco_live/products/SPP6.html

Michael DelMauro
Technical Support
T 732-223-6644 x 261
[email protected] | www.supco.com

Thanks for the great overview of the hard start kits. When I was researching generators I found this web site:

Link

Which has a picture showing his Fluke meter reading 22.6 A for the startup current of his tiny window 5000 btu AC unit, and a running current of 5A. Further down the page he shows his camping trailer's 13.5 Kbtu AC drawing 11.5 A running, but he doesn't show it starting up with the Fluke meter. That would have been neat to see. Interesting stuff. I can start up my AC with the Yamaha 2400 here at 5000 ft so long as I don't try to restart it shortly after shutting it off. The startup Cap would be pretty cool.

[rickst29]

I also visited his site as part of my long computer session yesterday. But thanks for "outing" the figure of 5000 ft. as the apparent max for the Yamaha to start the 9203 (unassisted). Yamaha says that the "2400" puts out 2400 watts peak, but I see lots of people on Internet boards are saying that it's more like 3000 watts (== 25 amps). So my 26 amp SWAG was maybe a little bit too high, or the instantaneous capability of the Yamaha is even higher than that widely held "more like 3000 watts" figure.

But the bottom line is: Even though your Yamaha EF2400is can struggle and start the A/C at 5000 ft, it's a heckuva lot nicer to the electronics of this $1200 generator/inverter to create a less reactive load by installing this $30 startup kit. (You should do it.) I've pretty much decided on blowing the big bucks, and buying a $$$$ pair of 45lb "2000 watt" generators with link-up. (Either the Hondas or the brand-new Yamaha 2000w generators.) My 4000w pair won't have any issues with starting the A/C, even at 7k altitude. But because a lot of stronger/younger TM owners do have the 71 lb Yamaha, or will be buying it, I wanted to provide a lot of detail about the kit and why it's a really great add-on, even if you can run A/C without it. (You know the price to replace that gen-set.... ouch!)

Per my initial post, RVP/Coleman provides a cheap compromise as standard equipment-- the run capacitor is 40 Mfd@370v, that's tuned for max efficiency, while the "fan startup" capacitor adds only 7 Mfd@370v for that purpose. There is no compressor start-up capacitor in the 9203 low-profile machine, RVP/Coleman simply left out the $10 of electronics and $7 capacitor which is needed by generator/inverters of this class as a cost-saving measure. (In my previous adventure of cleaning the indoor coil, I've taken my A/C apart completely and know how to re-assemble it from a pile of parts on the ground. I'm not just talking from the computer screen. BUT, from my memory of the free space surrounding the startup box/capacitor mounting, I'm not sure if there's room to add the Supco kit right next to current capacitors-- you might need to use a bit of #10 wire to mount it somewhere else.)

RVP knows their market AND their product very well, I would do exactly as they have done. Less than 2% of their customers will ever try to run this A/C with an inverter/generator which provides less than 3000w nominal "peak" capability. Conditioner. Others, like me, either pay the price (in extra weight or $$$$) to put bigger generator/inverter equipment on line, or they have shore power, or they leave the A/C turned off. The $17 per unit which it would cost to provide this feature at the factory goes straight to the bottom line, eating profit margin while competing with Dometic. The market doesn't want it.

But YOU should put it in, as should everyone running these A/C units with these smaller inverter/generators. Knowing all about it, I wrote this Thread for guys and gals exactly like you. The ones with strong arms and shoulders, who can pick up the Yamaha as easily as a box of Kleenex.

I appreciate the detail; I have it on my list'o'things to do this spring as we get ready for the summer season. It looks like a cheap and easy mod.

I'm guessing that the 13.5 Kbtu low-profile AC doesn't draw proportionally the same startup current as the guy's 5000 btu window unit or else we'd all be out of luck - I'm curious what it really is. Your swag of mid-to-upper 20's is probably about right. There's probably a market target of just under 30 Amps to keep circuit breakers from tripping (although I've run this off my wall power from my garage 20A circuit - hmmm I don't know how fast they really react I guess).

Anyhow, thanks again for doing the research on the kit.

Mark

[TM Pilot]

Originally Posted by rickst29

There is no compressor start-up capacitor in the 9203 low-profile machine,

rickst29,

I own a 2007 TM2619. It has the RVP model 9203C876 (9000 series; 92X3 Series) Polar Mach Low Profile A/C unit. While I have not disassembled the A/C unit and looked inside to visually confirm whether or not it has the RVP hard-start kit (part #9333-9021), all my paperwork shows that it did have it installed from the factory. In addition, my lights do not momentarily dim when I start the A/C unit.

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Installation Instructions for Hard Start Kit (9333-9021): http://www.rvcomfort.com/pdf_documents/1976288_copy.pdf

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Repair Parts List for 92X3 Series Polar Mach: http://www.rvcomfort.com/pdf_documents/r486_copy8.pdf

CODE: 4; USED ON MODELS: All; PART NUMBER: 9333-9021; DESCRIPTION: Start Device Pkg.

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Service Manual for...9000 Series Air Conditioners: http://www.rvcomfort.com/pdf_documents/1976141_copy.pdf
9000 Series Roof Mount Air Conditioners Wiring Diagram: http://www.rvcomfort.com/pdf_documents/1976364.pdf

Notice the wiring diagram for the 9000 series A/C unit shows the start capacitor & PTCR Start Device with solid lines. That means factory installed. If they were shown with dashed lines it would indicate optional (i.e. 7000 & 8000 Series A/C).

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Summary - The RVP hard-start kit (part #9333-9021) is suppose to be standard equipment installed by the factory on 9000/92X3 series Polar Mach Low Profile Air Conditioners.

There should be 3 capacitors on the 9000 series/92X3 Series Polar Mach Low Profile A/C unit:
1. Start Capacitor w/ PTCR Start Device (a.k.a. Hard Start Kit; Start Device Pkg.) 88-108 Mfd/250V.
2. Fan Capacitor 7.5 Mfd/370V
3. Run Capacitor 40 Mfd/370V

[TM Pilot]

My TM2619 is a 2007 model. However, it was built in July 2006.

Here is a related thread: http://www.trailmanorowners.com/foru...ad.php?t=12082

[Padgett]

Interesting, mine is a 2006 2720sl built in Apr 2006. Wonder when the TM model year starts.

[TM Pilot]

Today, I visually checked to see if I had the Start Capacitor installed in my RVP model 9203C876 (9000 series; 92X3 Series) Polar Mach Low Profile A/C unit (manufactured 2006). I removed the shroud (3 screws) and opened up the electrical junction box (6 screws). Inside were three capacitors (Run; Start; & Fan).

[rickst29]

But merely re-reading it after corrections to my first post. I now wonder whether the Supco behaves differently than the RPV standard part, and I also wonder whether earlier model years included that kit. Thanks!