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Davidlee64's avatar
Davidlee64
Explorer
Jun 21, 2017

A/C and Arizona Heat Wave

I am having AC and voltage related issues which have showed up with high temperatures. 118 yesterday, same for today, and who knows for how long. I started having cooling issues with the heat. My Mach 15 rooftop unit (brand new 4-29-17) quits putting out cold air when I need it the most. My portable A/C is giving me fits as well. It appears to me to be a voltage issue. I noticed my power strip indicator light was barely visible and flickering. After doing some research, I checked the available voltage. All 115v outlets show 121v without any load. When I turn on the rooftop unit it drops to 107.2v. Then I get the compressor shutting off, then coming back on after 5 - 8 minutes. It gets rather warm in here. Then after a while, the A/C breaker in the panel will trip. Low voltage = higher amp draw. There is also a thermal breaker that shuts down the compressor motor. When it resets, all comes back on. On the portable unit, it works fine for a while, but I think the low voltage is affecting it as well. The compressor kicks off and doesn't cool at all. I am going to open it up to make sure it is clean inside. It is running on a different circuit altogether, but I noticed one of the prongs on the plug is discolored and the end of the cord shows heat related melting. I checked the filters and one had about a 3" thick layer of dog hair on it. I want to inspect inside of unit for blockage.
  • 2oldman's avatar
    2oldman
    Explorer II
    Jun 21, 2017
    Assuming you're in an RV park, low voltage is a common problem. In spades lately. You'll damage it by trying to keep doing this. What a bummer.
  • Davidlee64's avatar
    Davidlee64
    Explorer
    Jun 21, 2017
    RV is at my house. I am not sure what gauge the wire is running to the outlet, or the the breaker on the outside wall from the house. It was already here and setup for an RV. There is a dedicated 30A cb for the RV outlet. I didn't feel like opening the panel to inspect the wire gauge. It is about 150' (min) from the house to the breaker box, and another 75' to the socket to plug into. I suspect a below minimum wire size as the conduit to the plug is 1/2" metallic.
  • 2oldman's avatar
    2oldman
    Explorer II
    Jun 21, 2017
    That's a long wire run. If not properly sized I'd say that's why. Can you move closer to the house and use another outlet?
  • DutchmenSport's avatar
    DutchmenSport
    Explorer
    Jun 21, 2017
    Heard on the news this morning that temps in Arizona hit 127. Topic was all the planes that can't fly.

    Don't know your situation, but maybe it's time to pack up and let those wheels carry you somewhere cooler for a while.

    Sounds to me the electricity is just being over taxed, and with the extreme heat, it's just not flowing good at all, overloading everywhere. Not much you can do about that, except leave. (Time for a vacation. I just saw your camper is parked at home! That really bites!)
  • MrWizard's avatar
    MrWizard
    Moderator
    Jun 21, 2017
    You don't say what your RV is tt, fiver, or mh
    But if it was me, i would be starting the generator
    Better to buy some fuel, than buy another new a/c

    That's what i had to do at my brother's place when a heat wave hit
    At night i could get by on the 20 amp shore power
    During the heat of the day, i ran the generator, to keep the A/C going
    It got up to 112F and 90 percent humidity
    I was able to share the load a little bit
    Plug the converter into the shore cord,
  • Davidlee64's avatar
    Davidlee64
    Explorer
    Jun 21, 2017
    Wire run was done by an electrician, I'm sure. I just want to verify wire size. Voltage is normal with AC unit off. But 12 v drop when on seems excessive to me. When air temps drop, both AC units work fine. My cell phone wouldn't charge either,lol.
  • Clay_L's avatar
    Clay_L
    Explorer
    Jun 21, 2017
    Davidlee64 wrote:
    RV is at my house. I am not sure what gauge the wire is running to the outlet, or the the breaker on the outside wall from the house. It was already here and setup for an RV. There is a dedicated 30A cb for the RV outlet. I didn't feel like opening the panel to inspect the wire gauge. It is about 150' (min) from the house to the breaker box, and another 75' to the socket to plug into. I suspect a below minimum wire size as the conduit to the plug is 1/2" metallic.


    I have a 120 foot run and I used 8 gauge wire.It works well.

    Some people will say that smaller gauges are rated for higher currents, but they don't realize that the voltage drop is a factor. Not just the ability of the wire to carry a given current. Both have to be taken into account.
    My wire size calculator says for 150 feet of 8 Gauge wire with a 30 amp draw there will be a 3.5% volt drop and there will about 15 1/2 volts available at the RV. Since you have an additional 75 feet with an unknown wire size. 8 Gauge may not be adequate.
  • Davidlee64's avatar
    Davidlee64
    Explorer
    Jun 21, 2017
    MrWizard wrote:
    You don't say what your RV is tt, fiver, or mh
    But if it was me, i would be starting the generator
    Better to buy some fuel, than buy another new a/c

    That's what i had to do at my brother's place when a heat wave hit
    At night i could get by on the 20 amp shore power
    During the heat of the day, i ran the generator, to keep the A/C going
    It got up to 112F and 90 percent humidity
    I was able to share the load a little bit
    Plug the converter into the shore cord,

    Genny sounds like an idea, but it needs a carb replacement. PO did a bang up job of fixing it. He was the silicone king. Glue everything back together or lose a few pieces.
  • 2oldman's avatar
    2oldman
    Explorer II
    Jun 21, 2017
    Davidlee64 wrote:
    I noticed one of the prongs on the plug is discolored and the end of the cord shows heat related melting.
    Yah, that's not a good sign.

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