AC Won't run on 30 Amps

Not sure what to title this thread but the bottom line is that our rear-most AC would not run on 30 amps but apparently will now on both 30 and 50 amps. This AC has run fine in the past on a 30 amp source to include my Honda E7000IS running either off 30 amp plug or the 50 amp plug (which puts out about 40 amps as I recall but uses both legs of the 50 amp coach electrical cord.) I think I said that correctly. Regardless, in early June we were preparing for a trip up to Utah and I was hooked to 30 amp power at home. The AC fan would come on but I never heard the compressor come on. After a few minutes the whole thing would shut off and then we'd wait a couple of minutes and it would start up again. Figured the couple of minutes to be the thermostat holding it off the two minutes (or so) to let the compressor pressure diminish (as expected if the compressor had been running). AC would start again, again no compressor noted, and the temp coming from the vents never went down (as measured using an infrared thermometer). Was not running either the middle or front AC at any time during this. Went on our trip, tried the AC one time enroute to Utah and it did the same thing -- we were on 50 amp service then.

Got back home and took it to our local RV dealer/maintenance where they tried it and supposedly worked fine. They worked it on 50 amp service and said it was fine. Told them to try 30 amp, which they did, and it worked for them - albeit, they melted the male plug on my cord (melted the top pin rubber and also one leg of the plug was covered with melted rubber when I got it home. They replaced the plug with a 'camco' yellow plug - not real happy about that but... In any case, after this long post, my question is - could a dying start capacitor cause something like this? Any one else have similar issues that seemed to fix themselves.

Football tailgating season starts in two weeks and it stays HOT here in Kansas for another month or two.

Sorry for the long post and hope it all makes sense.

Ron,

You didn't mention the PCS energy management system in your note. As you can see in the picture below, if you don't have enough power to supply the things drawing power, the PCS cuts power first to the Water Heater, and 2nd to the Rear A/C, leaving the blower running, but cutting power to the compressor. You can read more about this starting on page 42 of the Landmark 365 User Guide V1.1, in this folder. The PCS operation is also discussed in the Electrical user guide located in the same folder.

Keep in mind that there is at least 1 hidden load. The Power Converter can draw anywhere from 2-15 amps or even a little more, depending on battery charge and condition. If your water heater was set to electric, it could be drawing close to 15 amps.

Dan: Thanks for the quick reply, and for the reminder about the Water Heater. I did check the PCS manager screen (which showed all ON, nothing had been shut off by it), and the 120V water heater light was off, but as memory serves, there is another switch down in the water panel that would be on as well. I've always thought that it had to be on with the 120V as well but maybe not. I'll check it this weekend.
Ron

I would suspect the power cord or either end connection. The melted end would suggest a poor, high resistance contact resulting in overheating. Can you try another power cord?

Power cord is attached to the electric reel so not feasible. Thanks for the suggestion though.

I personally would go thru the entire 120V system from the power reel connection to the breaker bank... one connection at a time, suspecting each one being loose.

If you lost power to the A/C circuit breaker, I think both blower and compressor would stop. For just the compressor to stop, I think the freeze sensor is the likely culprit. And I believe the PCS system uses the freeze sensor circuit to shed the load when using too much power.

I would seriously look at the wire connections inside the cord reel. That could be the source of all sorts of bad things.


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For reference, this is what it looks like at the shore power electrical connection to the power cord reel. A metal cover protects it after the connection is made.


Link to more pics.