Forum Discussion

camplikeachamp's avatar
camplikeachamp
Explorer
Jul 07, 2017

newbie here - A/C issue - Help!

Hi all,

Just moved into a camper i bought to live in while i build my house. Having A/C trouble that I can't figure out. A/C will run for a while but then kick the breaker. It seems to cool the 30ft camper just fine for a while then the breaker kicks. It seems to last longer when the days are not so hot or when i turn the thermostat up to 75 or so. It has run as long as 5 days without kicking but has also kicked after a few hours. The power flashed last night then came right back on. I heard the air kick on, then an audible "buzzing" sound, then the breaker kicked. I flipped it back on and it's been running ever since. It's on a 20 amp breaker in the panel in the camper. I've switched out the breaker (twice) but that had no impact.Checked voltage and I have 122 volts at the breaker. I had an A/C man come out but he couldn't find anything wrong with it and stated it's not pulling high amperage or anything. He did state that his specialty is home HVAC units and he doesn't really have experience with camper units or wiring.

Is a 20 amp breaker normal for the A/C? I'm reluctant to switch out to a 30 amp.
Any ideas as to why this is happening? It's a duo therm unit. The camper is old, '96 model. I'm not sure if this is the original unit that came on the camper or not. I really hate to invest in a new unit since this is being used as a temporary residence.

Any advice would be greatly appreciated. It's only going to get hotter in Tennessee the next couple months. I could be in for a long summer if i can't get this figured out.

thanks!
  • camplikeachamp's avatar
    camplikeachamp
    Explorer
    Jul 13, 2017
    OK, AC man said there are 2 capacitors. First one is working correctly. Second one was busted. He replaced it today. I thought for sure that would fix the problem
    Wrong. Breaker kicked again this evening. I left it off for a while. Turned it back on and seems the fan has been running constantly since the new capacitor was put on. Unit used to kick itself on and off. Now it just stays on.

    I'm baffled that we can't get this fixed. I have hooked up a small secondary unit and vented out a window to try to give main unit a little help. Not sure what to do next....


    On iPhone. Please excuse typos
  • sayoung's avatar
    sayoung
    Explorer
    Jul 07, 2017
    camplikeachamp wrote:
    I have the camper plugged into a receptacle in my pole barn. It's on a 30 amp breaker in the barn and I have 10/2 wire ran for abou 30-40 feet to a (I think) 20 amp camper plug receptacle I got at lowes. Camper cord plugs in there and runs to small panel inside the camper. A/C unit itself is on a 20 amp in that panel.

    Thanks a lot for the suggestions. Guy at work thought maybe a capacitor as well. Hopefully I can find parts for a unit that old. Any suggestions on best place to look for a capacitor?

    You just answered your question.
    Get a rv 30amp receptacle on a 30 amp breaker . don't use a regular extension cord only the cord from the rv.
  • jyrostng's avatar
    jyrostng
    Explorer
    Jul 07, 2017
    any ac supply and most motor repair places, you have to know the size of the capacitor, the Microfarads and voltage (physical size relates to the voltage) call a ac man, he has a meter to tell you what MFD it is, or should have one. Most have the capacitor on the truck. did you look at the fan side of the back coil? Some of those capacitors have many wires on them, don't get ANY mixed up.
    Check your 20 amp plug for heat! the only adapter plugs I have seen are 15 amp rated
  • camplikeachamp's avatar
    camplikeachamp
    Explorer
    Jul 07, 2017
    I have the camper plugged into a receptacle in my pole barn. It's on a 30 amp breaker in the barn and I have 10/2 wire ran for abou 30-40 feet to a (I think) 20 amp camper plug receptacle I got at lowes. Camper cord plugs in there and runs to small panel inside the camper. A/C unit itself is on a 20 amp in that panel.

    Thanks a lot for the suggestions. Guy at work thought maybe a capacitor as well. Hopefully I can find parts for a unit that old. Any suggestions on best place to look for a capacitor?
  • stickdog's avatar
    stickdog
    Explorer
    Jul 07, 2017
    We were volunteering at a COE park and they gave all the volunteer an autoformer to use. They said when it got hot and everyone on the line were running AC the volts would fall off. We hooked it up and had no problems all summer.
  • jyrostng's avatar
    jyrostng
    Explorer
    Jul 07, 2017
    The extension cord you have suppling power to your trailer is usually the weak link in delivering power, make it as short and as large as possible with no adapters. when the compressor starts, it pulls roughly 5x it's normal current for a instant, that causes a voltage drop in the wire supplying the power. If it doesn't start in a second, the breaker trips.
    With it running, feel the cord and plug for heat, that heat Is the dropped voltage, too much heat equals lower voltage to the unit and higher amps through the breaker.
  • kerrlakeRoo's avatar
    kerrlakeRoo
    Explorer
    Jul 07, 2017
    How are you plugged in? Are you running on a 20 amp outlet from the construction power drop? Or do you have a standard 30 amp connection?
    The hotter days may have voltage issues from local high usage, causing fluctuations which are increasing your draw. If your running off a long extension cord on a 20 amp circuit it's likely getting hot.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Jul 07, 2017
    ScottG wrote:
    I'm thinking your hard start or run capacitor is failing. At that age, I would replace it/them as regular maint. items.
    (just did the one on my house)

    FYI, never try to restart an AC immediatley after a power intruption. The pressure needs to bleed down on it for about 5 minutes.
    It could have been damaged trying to do so.



    X2^^^^^^

    And yes ---20A CB is correct for rv a/c unit (13A--16A)
  • ScottG's avatar
    ScottG
    Nomad
    Jul 07, 2017
    I'm thinking your hard start or run capacitor is failing. At that age, I would replace it/them as regular maint. items.
    (just did the one on my house)

    FYI, never try to restart an AC immediatley after a power intruption. The pressure needs to bleed down on it for about 5 minutes.
    It could have been damaged trying to do so.

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