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Windowless A/C?

Post in 'The Green Room' started by cbrodsky, Jun 20, 2007.

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  1. elkimmeg

    elkimmeg Guest

    Mo mentioned the coolant problem but there is another one lack of returns will ice up systems I don't know what it is but it seems all Contractors have enought supplys but have a brain fart concerning returns Ac the returns should be located high in the rooms That one central in the upstairs hall is next to useless never moves air in the bedrooms Again a very ineffecient way.
    I will never pass a system where supply =returns and if a door can be closed then I consider it closed all the time and a separate return required..

    Again more emphasis is give to heat distrobution than AC Did you know Ac requires larger ducting than Heating yet for years combined systems sacrifice both task accomplishing neither effeciently or effectively... Let me ask a question have you increased insulation in the attic.. Improved windows? ( years old you should not be having these problems in designed and installed correctly.. Well do you have cheap ass builder special equipment? Before more money is thrown away and another idiot recharges a charged system lets figure out what you have and how it improve it I need some more info Trader I willing to bet with guidence you can make the improvements

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  2. elkimmeg

    elkimmeg Guest

    Mo instead of charging a system every year itime to figure out where the leakage is
  3. GVA

    GVA Minister of Fire

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    Also important to note here that the compressor will run 30 some odd degrees lower than the thermostat setpoint, (And no it doesn't get the room cooler quicker the lower you set it)
    so someone set's it to 60* on a nice hot humid day and guess what forms?????
    After years of climbing on the roof to thaw out the rooftop units I had My HVAC guy set up the units with some sort of switch so that no matter what the T-stat is set at the compresser will never drop below 36* (I think that's the temp)
    anyway The only time I have a unit freeze up now is if the condenser fan has a belt that is slipping, or belt breaks.....
  4. elkimmeg

    elkimmeg Guest

    Gva brings up another good point. Common practice is oversizing the compressors, which results in short cycling and freeze ups plus gross insffeciencys

    Couple in lack of adequate return systems and your have a formular that is doomed for failure
  5. Mo Heat

    Mo Heat Mod Emeritus

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    That would seem to be the proper course of action, and in fact, that is what I asked the technician to do. Judging by his demeanor and reply (and I wasn't at all impressed with this guy like I was the one I got the year before from the same company), and all his hemming and hawing, I concluded he either didn't want to do it, didn't know how to do it, or would have taken a long time to do it. At $150 per hour, with a reluctant and possibly incompetent technician, and with absolute zero guarantee (hee, hee) of actually finding the leak, and being able to fix it, unless it was one of the connectors along the run and not inside the nearly 20 year old heat exchanger, I decided to cut my losses and go with his recommendation of pumping some more cold juice in there.

    This guy was so disorganized (and a real BS'er of the worst kind... he called me "Bud" about 40 times) that he'd left the shop without any cold juice. That added another two hours onto the service call and I believe he padded the bill with an extra $35 in labor (nothing else was done and no explanation) to get something for the two hours he was smoking cigarettes out front in his air conditioned truck while waiting for another truck to deliver the cold juice. He was going to leave after changing his story about needing just a little more freon after his nearly spent tank gave out and he discovered he only had two empties in the truck instead of two full tanks. If I hadn't been out there watching and asking questions, he'd have left just to avoid the delay and I'd have had about one pound added instead of two. Nice guy. At least he responded to some deliberate questioning and came clean. I half expected him to pull a BS rabbit out of his hat and leave anyway.

    So, in the end, I paid up, since it was the same price as the year before and I didn't feel like arguing with a stump.

    Anyway, since topping up the unit worked last year, I figured it would work again this year, and it did: problem put off for one more year... as of now. When other people are involved, sometimes things don't go the way you want them to.

    It's cool in here, but now my thermostat is on the blink. It keeps resetting itself to the default factory set-back program so I'm shopping for a new one.
  6. tradergordo

    tradergordo Minister of Fire

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    I think its probably the coolant problem in my case, sure sounds like it anway. It did ice over once last year, but the first 7 years of its life were just fine. I guess I just wish I had something more efficient that's all. Yes, its a "builder special" Carrier model. To give the builder credit though I'm pretty sure its properly sized for my house and there are plenty of return vents (large and placed at the tops of the rooms and hallways).

    Anyone know if its possible to do a recharge yourself or to find leaks yourself? This goes back again to not wanting to spend money on a system I think I should replace, then again, maybe spending $200 to fix what I have is better than spending a lot more to replace it.


  7. elkimmeg

    elkimmeg Guest

    Trader there is a little more involved then just adding coolant after the system has been charged it has to be evaced usually accomplished using a vacume type connections and gages.

    Yes 7 years residual coolant loss is common enough to effect system preformance. Time to get it recharged that small copper coolant line can hold up to 150 psi better read up on how it is done before un doing that line Some suprises can be quite unpleasent
  8. begreen

    begreen Mooderator Staff Member

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    No, not legally at least. Freon leakage is a major reason for the degradation of the ozone layer. There used to be incredible, careless waste in the refrigerant industry. It's now tightly regulated. When a system is worked on or purged, all evacuated freon is supposed to be captured and recycled.

    Best to have the system gone over with a halon gas leak detector. That you can do by yourself if you buy the tool. Then have the leak(s) fixed by a reliable mechanic and the system recharged. Given that this is happening to multiple core forum users, maybe you could all go in on the price of the tool and share it?

    http://www.reliabilitydirectstore.c...838-Refrigerant-Leak-Detector-p/rdi-ar838.htm
  9. tradergordo

    tradergordo Minister of Fire

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    That's probably not a bad idea (sharing a detector) but I did a bunch of research and based on what I read, virtually all air conditioners leak - its just a matter of how fast. A seven year leak it seems is not unusual, it would probably be impossible to detect even with expensive equipment being used by a trained technician. Now if I recharged it and just as much had leaked out within 2 years, then it would be considered an unacceptable leak (this applies to car air conditioners as well from what I read). I also see that it is illegal to do the recharge yourself (for central AC, but not for automobile) so I guess I don't have much choice in my case as far as a do-it-yourself solution.
  10. begreen

    begreen Mooderator Staff Member

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    That's assuming that it leaked gradually over 7 years. It might have been fine for 5 years and leaked over just 2. I have a hard time buying into the notion that all systems leak. Automotive systems have more confounding factors (vibration, hoses instead of hard-plumbed) and can go 12 years or more without a leak. Refrigerators can go over 20 years and still work. My suspicion is that most A/C system leaks relate to the quality of installation. First suspect would be flare joints, then welds.
  11. tradergordo

    tradergordo Minister of Fire

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    For what its worth - I had the AC repair guy come out last night. My central air unit was short about 3/4 lb. of coolant (which isn't a real big loss, but enough to cause problems). The guy showed me another way to quickly test performance - the air coming out of the registers should be between 17 and 22 degrees cooler than the air going into the return vents. At the time, the air going into the return vents was 83 degrees, and the air coming out the register was 72 degrees. After adding the coolant it almost immediately went down to 68 degrees, and when I checked it later, it was down to 58 degrees (right around the optimal 22 degree difference). We are having a heat wave in PA right now, high of 94 (that's hot for us) and the wife says the AC is working better than ever so I guess the $148 was worth it.

    For what its worth, I also learned that a typical rule of thumb for sizing a central AC unit is about 1 ton per 600 square feet of area to cool. At 3.5 tons, my unit is considerably undersized for my house (thanks a lot Mr. Home builder!). Although to tell you the truth it performed quite well for its first 8 years and its doing fine right now after the coolant charge so maybe the builder didn't really screw it up...

    One nice feature I see on a lot of new homes today is a metal shelf permanently fixed to the foundation of the house that the outside air conditioner sits on - this prevents damage (leaks!) from shifting ground underneath the AC unit, I think its a very good idea, probably also helps a little to keep mold and critters (bugs, mice) from getting inside the unit especially in the off season.
  12. Mo Heat

    Mo Heat Mod Emeritus

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    Glad to hear it. I know the relief you must feel since I went through the same thing the last two years (I might actually benefit from finding my leak). Nothing like cool, dry air inside when it's sweltering outside.
  13. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    On the charge it yourself front, I used to charge my own. I kept an eye over my shoulder since the last time I checked the max Fed fine for a Freon discharge to atmosphere was $250,000. Of course a friendly judge could cut it down to some easily managed figure like $50,000 or so.
  14. Kilted

    Kilted Member

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    Super Efficient Air Conditioner

    Checkout http://www.coolerado.com/

    Check out the videos page:
    http://www.coolerado.com/CoolSchool/CoolSchool.htm

    So I know nothing about this unit. A friend dropped this on me today. Hopefully some one here knows a little about HVAC systems.

    Since the working fluids here are air and water this is essentially a swamp cooler, with the difference that the swampy air stream is directed outside.

    In one of the video's He is using a space heater to provide hot dry air as input this seems to make the demo unit work well. There are charts showing what parts of the country this system works in. It would seem to work in a hot dry climates. It would work best in an attic vs outside. The attic providing hotter air than ambient outside. Another problem I see is volume of cooled air, because of restrictive airflow air delivery could be lower than required.

    There is an evaluation by PG&E;you need to wade through some math.

    -- Brandy
  15. Sandor

    Sandor Minister of Fire

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    You should thank your builder. Oversized A/C units will cause many problems. The largest problem is that the unit does not run long enough to effectively de-humidify.

    Everyone is way better off undersizing than oversizing.
  16. begreen

    begreen Mooderator Staff Member

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    This is not an air-conditioner but a sophisticated, indirect evaporative cooler. It would work ok in dry climates, but my guess is it would be sub-par in the humid heat folks are experiencing back east.

    From the executive summary of PG&E;'s testing:
    The advantage of an indirect evaporative cooler is that it accomplishes low-cost evaporative cooling
    without adding any moisture to the air supplied to the conditioned space. However, the high flow
    resistance of the heat and mass exchange modules in this unit resulted in significantly lower supplied
    airflow and higher power consumption relative to typical direct evaporative coolers.

    In other words, it doesn't work as well as a direct evaporative cooler, but does have the advantage of not adding humidity to the air that is typical with direct evap (swamp) coolers.
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