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Thread: A/C hard start capacitor install, not sure if it worked

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    Member northernalberta's Avatar
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    Default A/C hard start capacitor install, not sure if it worked

    So last summer while bringing my new-to-me travel trailer (2010 Springdale) back up the highway from Seattle, I noticed the A/C took a HUGE power draw, like it would flip the campground breaker if it was just a 15A hookup... then I tried it from the 3500W generator I'd bought, and it bogged down the gen really badly for several seconds and never did start the compressor. I gave up and never tried again.

    So I found this online:

    http://www.modmyrv.com/2009/05/27/rv...tart-capacitor

    I bought the SPP6 capacitor, got up on the roof, and followed the instructions to install it. It's not real clear if the capacitor is "directional" (ie, both lines coming out of it are identical, black) but I plugged it in to the existing run capacitor. There was no pre-existing start capacitor, just an empty space next to the run capacitor so it fit perfectly. Here's a video that very closely depicts what I did:

    http://www.youtube.com/watch?v=oHgXGlYNYkQ

    So I fired up the generator and tried it out just now. It immediately starts the fan blowing, but because it's 60 F outside I can't really tell if it's blowing air conditioned air or just fan air. I did NOT hear the generator bog down significantly nor did I hear the telltale sound of an a/c compressor kicking on.

    What should I try next? I was thinking maybe I fried the run capacitor last time I tried to start it... so I could always replace that. Or, maybe at 60 F it's simply not hot enough for the thermostat to send the message to the compressor to kick on?!?!?

    Thanks

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    Quote Originally Posted by northernalberta View Post
    What should I try next? I was thinking maybe I fried the run capacitor last time I tried to start it... so I could always replace that. Or, maybe at 60 F it's simply not hot enough for the thermostat to send the message to the compressor to kick on?!?!?

    Thanks
    Use your wife hair dryer on the thermostat to simulate hot weather, just don't get carry away with the heat.

    PS do you have it on FAN not air conditioned ?

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    Member northernalberta's Avatar
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    Hmm... I'll try the hair dryer tomorrow, thanks.

    There's a switch that goes Furnace->Off->Air Conditioning. Then a separate switch that says Fan: Auto/On.

    If the fan is in the "On" setting it will start running the fan. If the other switch is switched over to A/C it will also run the fan.

    Quote Originally Posted by MacGyver View Post
    Use your wife hair dryer on the thermostat to simulate hot weather, just don't get carry away with the heat.

    PS do you have it on FAN not air conditioned ?

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    The only really good way to check things out is with an amp clamp.

    If the compressor is running you should be able to hear it. Hard start kits work pretty well on sluggish compressor but won't turn over a locked up one.

    If the compressor pulls locked rotor amps (something like 40 or 50) and then 0- that's the internal overload opening on the motor winding. The compressor is locked up.

    Normally you'll pull 30-40 for about 1-2sec and then it'll settle down to 8-12A or so depending on load and size.
    "I do not deal in hypotheticals. The world, as it is, is vexing enough..." Col. Stonehill, True Grit

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    Member northernalberta's Avatar
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    Thanks... I don't have an amp clamp, will a multimeter work? Which wires would I be metering? Do you think the compressor is a more failure prone part than the run capacitor?

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    Member northernalberta's Avatar
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    I tried the hair dryer and didn't notice a change. I might as well open the purse strings and ask a local RV shop to troubleshoot the A/C before I hit the road. I'm getting in over my head with HVAC issues.

    As a last-ditch I may ask the same questions on a dedicated RV forum or HVAC forum but if it comes down to replacing parts beyond the capacitors then I really don't know what I'm doing.

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    I would take it to someone that repaired air conditioned unit before I would go to an r/v repaired shop.
    IMO

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    Member hodgeman's Avatar
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    Quote Originally Posted by northernalberta View Post
    Thanks... I don't have an amp clamp, will a multimeter work? Which wires would I be metering? Do you think the compressor is a more failure prone part than the run capacitor?
    Multimeter won't do that one. Run capacitors frequently fail...but so do compressors unfortunately.

    I'd look for a HVAC guy to check it out and give you a diagnosis.
    "I do not deal in hypotheticals. The world, as it is, is vexing enough..." Col. Stonehill, True Grit

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    Member northernalberta's Avatar
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    Thanks for the tips; is there anyone you guys would recommend?

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    Member northernalberta's Avatar
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    Exclamation

    Gentlemen, I un-installed the hard start capacitor and lo and behold, it is back to at least trying to kick the compressor on but killing my generator in the process. It wouldn't even attempt to start with that capacitor added. So I have plugged it into the house and that compressor is running and it's blowing ice cold air.

    Which leads me to my question, is it possible to plug in a capacitor backwards, and somehow cause the system to need an even greater load to start it than without? I couldn't tell if there was a forward and reverse way to plug in this capacitor. Both wires coming out of it looked identical. I did take physics and learn about capacitors back when I had hair, but I'll be ****ed if I can remember what I learned.

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    All the starting capacitors I've seen do not have polarities.

    Is there I.D plate on the AC that said what the voltage and current or wattage is? Also what is the information on the generator?

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    Member northernalberta's Avatar
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    Well, what do you know!! I hooked the hard start capacitor back up again in the reverse direction and now the A/C runs fine, and it starts with a noticeably lighter load. The generator's rpm just drops when the compressor kicks on, but has no trouble powering it.

    I think the A/C is a roughly 13,500 BTU and I have no idea what the wattage was... didn't see that printed anywhere on it. It's a 3500W genny I got cheap at Cabelas.

    Quote Originally Posted by MacGyver View Post
    All the starting capacitors I've seen do not have polarities.

    Is there I.D plate on the AC that said what the voltage and current or wattage is? Also what is the information on the generator?

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    Nothing is making any sense.......If it was me I would reverse the capacitor to see what happen.

    Does it really matter........I think not IT WORKING....... that all that matters...........walk away and don't look back.

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