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  1. #14
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
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    7,750
    Quote Originally Posted by SonicExplorer View Post
    Many thanks to all who replied.

    To clarify: One shingle layer, attic ducts, lineset under ground (under the slab).

    I suspect a combination of slightly dirty condensor mixed with ventilation that is just not keeping up. Now, could be NEW heat generated by the new roof or it could be the SAME heat just not ventilating as well with the new ridge vent.

    The other possibility, as somebody pointed out, is maybe a slow leak. I did notice something today that I do not recall seeing before... On the liquid line where it connects to the drier outside of the condenser I am seeing what looks like little "blisters" in the copper at the braze joint. Would this by chance be a symptom if Puron had been slowly leaking? I will try to take a picture and see if I can figure out how to upload it....
    its probably just excess solder on the joint, but a picture would confirm.
    Heating/Cooling Services Inc.
    www.andersonhvacservice.com

  2. #15
    Join Date
    Nov 2010
    Location
    Central Florida
    Posts
    556
    Quote Originally Posted by jtrammel View Post
    its probably just excess solder on the joint, but a picture would confirm.
    If you mean "bumps" or "lumps" that sometimes are seen on/near a solder joint, it isn't that. It literally looks like something blistered the copper. Tomorrow I'll take a pic.....

  3. #16
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
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    7,750
    Quote Originally Posted by SonicExplorer View Post
    If you mean "bumps" or "lumps" that sometimes are seen on/near a solder joint, it isn't that. It literally looks like something blistered the copper. Tomorrow I'll take a pic.....
    sounds interesting
    Heating/Cooling Services Inc.
    www.andersonhvacservice.com

  4. #17
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,376
    Sure would have been nice if you could have gone with a "cool roof" material. If you can't get the ducts out of the attic, and you can't insulate the roof deck, nothing beats a cool roof for reducing attic temperatures.

    That said, if you haven't had your a/c serviced for the summer, do it now. If you get it working in tip top shape and it still seems to underperform on hot days, you then know your new roof and/or ridge vent may be the culprit. I'm not all that confident ridge vents reduce attic temps all that much, but they are better than nothing.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  5. #18
    Join Date
    Nov 2010
    Location
    Central Florida
    Posts
    556
    Quote Originally Posted by Shophound View Post
    I'm not all that confident ridge vents reduce attic temps all that much, but they are better than nothing.
    It would help if I had an idea of what a "normal" temp is for an attic in Florida with passive ventilation. Right now, I am seeing a 30 degree delta between the attic and the outside temps when at the peak heat of the day lately (about 90 degrees outside). So I'm reading ~120 degrees which seems ridiculously hot to me. I don't recall the attic feeling that hot before but then again I never measured it previously. Attic is about 10 feet high and I'm measuring at mid height, but higher up at the peak of the roof I bet the temp is at least 5 degrees hotter yet. Can't imagine what is going to happen when we get to the 95-100 degree range soon with high humidity....

  6. #19
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Attic temps are mostly driven by the solar heat gain on the roof. The attic temp when it's 90F outside isn't a lot hotter than when it's 85F outside.... probably just 6-7F hotter in the attic. Humidity doesn't drive attic temps.

    "cool roof' desings unfortunatly are pretty foreign to most roofers. Plus it's more expensive for the homeowner even though steel roofs last a lot longer and ithe cost difference will pay for itself within probably 10 years... less if you can use tax credits.

  7. #20
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,376
    Quote Originally Posted by SonicExplorer View Post
    It would help if I had an idea of what a "normal" temp is for an attic in Florida with passive ventilation. Right now, I am seeing a 30 degree delta between the attic and the outside temps when at the peak heat of the day lately (about 90 degrees outside). So I'm reading ~120 degrees which seems ridiculously hot to me. I don't recall the attic feeling that hot before but then again I never measured it previously. Attic is about 10 feet high and I'm measuring at mid height, but higher up at the peak of the roof I bet the temp is at least 5 degrees hotter yet. Can't imagine what is going to happen when we get to the 95-100 degree range soon with high humidity....
    What gets lost in discussions concerning ventilated attic air temperatures is the surface temperatures of the roof deck, roof trusses or rafters, and the exposed surfaces of insulation on the attic floor, and the ducts in the attic. If you are seeing attic air temperatures around 120 degrees F, you can be confident the roof deck is much warmer than that. In turn, that hot deck radiates directly down to the insulation and ducts, heating them up in the process.

    By increasing attic air ventilation, it may reduce air temperature, and provide a small heat sink for the ducts and attic floor insulation to dump their surface heat into, but by far the greater heat sink all of this heat WILL migrate toward is the cool interior of your house, and the cool air traveling through the ducts.

    In your case, while it may be true your old ridge vent worked better than what you have now, what may be worse is that your new shingles soak up more heat than the old ones did, for whatever reason. You did mention that you went from three tab to architectural shingles. I have no data at the moment to support my notion, but I would be curious to know if there is a difference in the emissivity and reflectivity characteristics between what you had before and what's up there now.

    Regardless, get your a/c system serviced and cleaned. You need a reference point to determine which component is at fault; the new roof or the a/c.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  8. #21
    Join Date
    Mar 2009
    Location
    Mount Holly, NC
    Posts
    3,496
    one thing I've seen on roofing redoos is changing from gable to ridge... and lack of airflow... soffit vents are where the air enters, ridge is where it exits...

    if the house has gable, and ridge is added... the ventilation does not cool the attic...

    since you had ridge before, likely this is not the problem, but I thought I'd mention it.

    heavier shingles do retain more heat, and more heat has to go somewhere.
    The TRUE highest cost system is the system not installed properly...
    The three big summer hearththrobs...
    Mel Gibson
    Dwane Johnson
    The A/C repairman

  9. #22
    Join Date
    Nov 2010
    Location
    Central Florida
    Posts
    556
    After climbing through the attic last night I found the last two rafter bays in the back corner of the house are not insulated, and after checking just now in the heat of the day the drywall on the ceiling feels very warm from below. This is a tiny amount of over all space of the house ceiling (about only 50 square feet at most, and has been this way all along. Hard to describe, but that area of roof in the back corner has an "extension" most of which sits on the real roof and they obviously couldn't get in there to blow insulation. I'll have to see if I can find somebody to do this, maybe go in through the side soffit or something. This is still only a symptom of the bigger problem though - which is either the attic ventilation or the AC.

    Attached is the picture I promised. I wonder if those blisters are just copper rust. The effected area is in sunlight all day and directly under the drip eave so it gets rain and night condensation dripping on it. Maybe I should cover it with some insulation?

    Please let me know what you guys think, if it is a likely indicator of a Puron leak...

    Name:  20130526_151106.jpg
Views: 72
Size:  40.2 KB

  10. #23
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,376
    Am I seeing two driers (the blue and the black cylinders on the pipe) in line with one another? If so that might be part of your problem!
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  11. #24
    Join Date
    Nov 2010
    Location
    Central Florida
    Posts
    556
    No, the black thing you see is just a rubber "seal" I put over the line because the line enters a black poly pipe before it goes under the slab. Since the line is under the drip eave I was concerned it may allow water to run down the line and into the pipe and fill with water over time, so I put a rubber stopper on the line to seal the pipe. It's a rubber foot used for chair legs, simply drilled a hole in the center, slit down the side and put it over the line & pipe.

  12. #25
    Join Date
    Nov 2010
    Location
    Central Florida
    Posts
    556
    Quote Originally Posted by Shophound View Post
    What gets lost in discussions concerning ventilated attic air temperatures is the surface temperatures of the roof deck, roof trusses or rafters, and the exposed surfaces of insulation on the attic floor, and the ducts in the attic. If you are seeing attic air temperatures around 120 degrees F, you can be confident the roof deck is much warmer than that. In turn, that hot deck radiates directly down to the insulation and ducts, heating them up in the process.

    By increasing attic air ventilation, it may reduce air temperature, and provide a small heat sink for the ducts and attic floor insulation to dump their surface heat into, but by far the greater heat sink all of this heat WILL migrate toward is the cool interior of your house, and the cool air traveling through the ducts.

    In your case, while it may be true your old ridge vent worked better than what you have now, what may be worse is that your new shingles soak up more heat than the old ones did, for whatever reason. You did mention that you went from three tab to architectural shingles. I have no data at the moment to support my notion, but I would be curious to know if there is a difference in the emissivity and reflectivity characteristics between what you had before and what's up there now.

    Regardless, get your a/c system serviced and cleaned. You need a reference point to determine which component is at fault; the new roof or the a/c.
    Excellent observations, and very true. The metal connection points on the trusses near the peak are scalding hot. So yes, lots of heat being transferred through the trusses and decking. Would it be worth the effort if I were to buy some wall insulation and lay it over the ducts that lie across the highest cathedral part of the attic, and also wrap the duct juncture boxes in the same insulation? I can do that for not too terribly much cost or effort if it would provide some meaningful benefit.

  13. #26
    Join Date
    Mar 2009
    Location
    Mount Holly, NC
    Posts
    3,496
    Quote Originally Posted by SonicExplorer View Post
    Attached is the picture I promised. I wonder if those blisters are just copper rust. The effected area is in sunlight all day and directly under the drip eave so it gets rain and night condensation dripping on it. Maybe I should cover it with some insulation?

    Please let me know what you guys think, if it is a likely indicator of a Puron leak...

    Name:  20130526_151106.jpg
Views: 72
Size:  40.2 KB
    in the picture, I see a copper reducer, and standard welding. I also see a small amount of rust on the dryer. I see nothing that would indicate a leak.

    it looks like a poor job of welding, but it should not leak.
    The TRUE highest cost system is the system not installed properly...
    The three big summer hearththrobs...
    Mel Gibson
    Dwane Johnson
    The A/C repairman

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