Air Conditioner Start Cap Replacement/Upgrade

Last Sunday, while preparing for a 3 week outing and luckily still at home, the A/C shot craps and stunk up the camper with a terrible burning electronics smell. This happened right at first startup (for the day) when the compressor tried to kick on. I pulled power and crawled up on top to have a look. Just as I thought, the starting capacitor had puked oil and the "motor relay" had a gaping charred hole in it. See black cap and black square thing attached on top of cap in pic. Of course I got online and found this to be a common problem with these A/C units. Mine is a 3 1/2 yr old 9000-series Polar Mach (read no warranty). I found a bunch of good ideas over at rv.net about upgrading the start cap/relay with something more robust commonly referred to as a 'hard start kit'. I was lead to the Supco SPP6 or 6E as a suggested easy fix. So on Monday I tracked down an SPP6 at a local Johnstone supply store. (Also very easy to find online if you're not in a hurry!) See pic. It was $15.10 including tax. It was easy, very easy to replace. A simple remove old cap and wires and plug in two new wires. Tools needed are a screw driver for disassembly and side cutters to cut plastic zip tie. New start cap is larger but easily fits in place. See pic.

While I had the A/C open I removed the 4 paper wasp nests (vacant), vacuumed out the pine needles and other debris from inside and also gave the coils a thorough cleaning. I liberally sprayed them with the Totally Awesome Cleaner and let it soak for 10 minutes or so. Then sprayed it off with the hose sprayer. The coils now literally look brand new again. It works!

I also took some time to inspect the compressor, tightened its mounting and also figured out the source of a slight buzz/rattle we had in the A/C. I found the black rubber covering on the lower line had moved and was allowing the line to rub against housing. I slid the rubber back down and tightened the zip tie. See pic. Again easy to do. Shell back on, 3 screws to tighten and she's ready to rock and cool!

The really good news came when I powered her back up. The compressor started with the greatest of ease. I mean smoooth! Granted I've only had the TM for 2 months, but the compressor has never started or ran this smoothly and quiet before. Compressor 'thump' and growl - gone. So was the rattle. I had to grab my SPL meter. In low cool mode I measured 70 dBc sitting on the couch. This is with the sound dampening material in place as well. Outlet temperature was a chilly 51 degrees. Outside was 86 degrees.

What did I learn? A good A/C service once a year to clean things out and tighten things up should be a requirement. The internet forums are awesome! and Carry a spare SPP6 kit for you or your camper neighbors. Who knows when the marriage you might save could be yours! or atleast the camping trip?

Careful though... Before attempting this repair make sure the power to the camper is OFF, work slowly, and make sure to short across the terminals on all the capacitors with a screw driver before touching the leads to avoid a shocking surprise.

Troy

Lots of good information! Thank you very much!

[Bill]

Troy -

Do you have ANY IDEA how much money you just cost the RV repair places???

In another thread somewhere, I recently posted my story about having an RV repair shop in southern Maine replace the entire air conditioner, at a cost of many hundred dollars - most of it covered by warranty, to my great relief - when it exhibited the symptoms you describe. Only later did I learn about this failed capacitor problem. And only now, in reading your thread, did I learn of a good source for a repair kit.

Thanks

Bill

Bill

You are truly welcome! That is what I mean about the awesome power of the internet! I've been online since 1995 and still things amaze me.

Your A/C replacement story reminds me of a recent conversation with a co-worker who had a "buzz" with his new Honda CRV. After 2 replacement A/C compressors, new engine mounts, 2 different dealers (all under warranty) and no fix they finally determined, by reading the internet no less, that one of the lines from the A/C compressor runs close to the frame and rattles occasionally causing the "buzz". A simple piece of rubber and zip tie and problem is gone. Duh!

Wouldn't you like to have that "bad" A/C unit? Put it in your storage garage as a back-up. Kinda like my rust bucket water heater! LOL!

IME the Supco SPP6 is a very good "like-for-like" replacement/upgrade. The existing starting capacitor on my A/C unit was a Mallory electrolytic 88-108 micro farad rated at 165VAC. The SPP6 is a 88-108 micro farad rated up to 288VAC. The higher voltage rating is a very good thing in this case. The other defunct part is the mysterious "Motor Starter" aka a PTCR or Positive Temperature Coeffiecient Resistor. The SPP6 contains a more robust version of this as well. Another suitable replacement, again IME, is the SPP6E. It uses the same size starting capacitor but uses a little bit different technology as its motor relay. It allows a quick restart capability and has a few more bells and whistles... I would have used it had they been in stock at the local Johnstone supply. I actually have ordered one now as a back-up for me or our neighbor.

I still can't get over how dang smooth and quiet the A/C runs now! I think they just need a little TLC and a few tweaks! I hope it's loud enough to drown out all the all-night camp music jams in Winfield.
Troy

Troy in your description you did not list a new capacitor but in your illustration I see a new one, what number did you use?

Francis
I used the Supco SPP6 hard start kit to replace the defunct compressor starting cap/relay. It includes a new start capacitor and PTCR device. Or are you referring to the gray capacitor? The gray cap is either the compressor run cap or the fan motor run cap (can't remember for sure). I did not replace it. I just swapped position of the caps and put it towards front when I re-assembled things.
Troy