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    bowca12's Avatar
    bowca12 Posts: 3, Reputation: 1
    New Member

    Jun 11, 2010, 03:03 PM
    A/C works great in all but one room
    My home is about 4 years old, a/c works great in most of the house. However, we recently upgraded one of the extra rooms to a nursery from being just a guest room. No problems during the winter months and early spring, but now that it's summer... different story. That single room is blowing about 10 degrees warmer than the other vents throughout the house. A/C guy came out and verified it. He checked the charge on the system, which is good. He then checked the coils and it turns out the top 1/3 of the 5-ton Goodman coils is warm, not cold. He then confirmed that the furnace and outside unit are both 4-ton. All the ducts are good to go, no leaks, connected correctly. My problem is that this one room blows room air tempurature air while the rest of the house blows nice and cold. Any other suggestions on a fix? If the installer screwed up, do they normally correct issues like this?
    cdad's Avatar
    cdad Posts: 12,697, Reputation: 1438
    Internet Research Expert

    Jun 11, 2010, 03:52 PM

    Here is the problem. You already had it checked out by a professional. Is it possible that the way it is routed your getting extra heat from it? Does it have the needed insulation? Is there nothing restricting the duct?

    Do you know what type of piping you have for your vents? Is it metal or plastic?
    bowca12's Avatar
    bowca12 Posts: 3, Reputation: 1
    New Member

    Jun 14, 2010, 06:52 AM

    The a/c guy checked the duct, said it's routed well, no kinks, insulation is good, sealed up tight. He even pulled it off the plenum to make sure there was nothing going on in there. He said the air may not be mixing well with the cold air blowing through the coils since this duct hooks up to the plenum near the top and front, where the coils are not cooling.

    The vents are metal, and they are mounted through the ceiling. Also, the attic insulation is good around them.
    bowca12's Avatar
    bowca12 Posts: 3, Reputation: 1
    New Member

    Jun 14, 2010, 06:33 PM

    Closing this. Called Goodman and they said that 5-ton coils are okay with 4-ton compressor and furnace. Getting new, longer plenum to give the air more time to mix before being forced into ducts. We'll see... Thanks.
    jonwillard's Avatar
    jonwillard Posts: 5, Reputation: 1
    New Member

    Mar 21, 2019, 07:30 PM
    First thing, most guys start a heating company because they see dollar signs. They think they can throw anything in as far as ductwork and it'll work. Not true. I fixed a system which had 3 areas in which the air hit flat surfaces to make a 90 degree bend. After we put scoops in to make the air flow the vents blew wonderful air. You have to look at the trunkline. Does it have scooping turns? Most trunklines have a split. Most guys don't care, they started a company for the dollar signs and think ductwork works off straight pressure. It operates off airflo AND pressure. They make dampers. You can take the 6 inch runs off the trunkline and install a damper. You drill 2 holes in the metal and manually adjust the damper. It's simple, you take the run loose, drill 2 holes, pop the damper in, screw on the handle, and it's best if you get your good pal to crawl under the house and adjust the dampers and then tighten them down. Sounds like someone didn't give a when they put your system in. Generally guys don't. You could install dampers (which are 10 bucks a piece at Home Depot) and adjust ALL of them forcing more air into the end rooms, OR you could raise the size of the run from 6 inch to 8 inch and put a damper in them. Increasing them to 8 inches (depending on how long they are) would be easier than installing dampers in the runs and adjusting each of them. Also, a lot of guys use ALL flex line for the runs and the flex could be collapsed or run ty. Crawl under the house and use common sense. Are the pipes or flex lines going to those rooms run smooth, flat, and even? If so, go to Home Depot and buy some 8 inch flex or pipe, an 8 inch takeoff or collar, an 8 inch damper, and upsize the runs to 8 inch. You'll need the dampers because they'll put out a lot more air and you might have to shut them down some. That's what I'd do. OR, you could cut a new takeoff in the trunkline and add another 6 inch run to the room. Have your buddy crawl under the house, YOU knock on the floor, drive a nail through the floor, and have your buddy tell you how far to the left or right the joist is, You mark it and mark your 4 by 10 cutout (the opposite way of the joist). Then you cut your rectangle out, nail the "boot" (after you insulate it) to the joist, then stick a finishing nail into the non joist side into the osb board, and then you go underneath to cut your hole in the duct, mount the collar or takeoff, and run your pipe or flex. Flex duct is cheaper than buying galvanised pipe that snaps together and insulating it. The regular snap pipe has better airflow. You'll get more air out of the straight snap together pipe. My company puts in the snap pipe after they insulate it and uses a 2 foot piece of flex duct at the end to make it quiet, if you use all pipe it'll make a slight noise. Add a 2 foot piece of flex it dampens the noise of the air hitting metal. So it's up to you. First, go under the house and see what the runs that lead to the floor registers look like. Use common sense. If they're saggy and loopy, well tightening them so they're straight might fix it. If not, upsizing to an 8 inch run would probably be my option as it's the easiest. Don't forget the dampers. The ductwork install is common sense. Cut the insulation back, lay your collar on the trunkline, trace the inside, and cut with snips. You can call me at 804 926 3429 my name is Jon. I worked for a company and did nothing but ductwork for many years. I can tell you what to do. If you have fiberglass ductboard as a trunkline the HVAC company ed you and could give a rats less, and you need it replaced. Ductboard has been banned in 2 states. You want metal.
    jonwillard's Avatar
    jonwillard Posts: 5, Reputation: 1
    New Member

    Mar 21, 2019, 07:45 PM
    It's easy. Go to Home depot and buy a damper. It's a flat piece of metal with a spirnged bolt on one end and a solid bolt on the other. You drill 2 holes in the fixture where that room comes off the trunkline. You take the pipe or flex loose and stick the two bolts through the holes, then you put the handle on it and screw the nut night over the handle. The flat piece of metal shuts off air from entering the line. You close it off a little and see how it works. If it's still too much air, you close it off some more. Air blows across the coil and comes into the trunkline at one temperature. That air blows into every room at that temperature. Due to the nature of the trunkline (some runs just pick up more air), some runs may require a damper to "balance" the airflow. It's a flat piece of metal that has 2 bolts and you turn it in order to block air from entering that run to a room. It's easy. If someone bull ted you about coils, you need me to drive to your state and beat his dumbass for lying to you and trying to get your money. Go to home depot. Tell them you need a damper for a ductrun to a room. Most runs are 6 inch round. Go measure it first. Tell the Home depot your trying to block some air flow to a room and he'll tell you what's up with the damper. Don't pay anyone 200 bucks to you. I'd probably do it for free if you paid for the damper because the I've seen doing HVAC is a bunch of guys making money who could give a less about you and your family and your bills. Pisses me off. I worked for Lin Jarrett Heating and Cooling in Petersburg VA and he knocks people's power bills down and we seal all our ductwork, use sweeping turns, do it RIGHT, and we don't people. He makes all his ductwork and doesn't use "boxes" on the end of furnaces, he uses ALL sweeping turns and has sheetmetal mechanics cutting out fittings in the shop. They get quality. I learned from the best, Melvin "Red" Daniels, a sheetmetal tech and he always taught me to do it right. He was old school, he'd throw a piece of flat metal on the layout bench and cutout any fitting you wanted except a square to round. Unfortunately he passed last year from liver cancer. He taught me to do it right and not people. He was the best at what he did. Too bad every company out there didn't have a Melvin Red Daniels to show boys how to do things right. Guys today think anything'll work and they'll throw any sort of system into your house. Got to be able to balance the system.

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