DIY - adding central air

I want to add central air to my existing forced air furnace. I see many available kits and it looks pretty straight forward. Any one done this? Also all the kits, I have seen, use Freon. Any one know of any that use 134A.
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calhoun" <builderpaul@"pants wrote:

Let, me suggest, this is not a do it yourself project.
Have you done the calculations to determine the size unit you need? Have you done the calculations and design work to assure your existing air handling system can handle A/C? Do you know how? I seem to recall that in the US you need a license to handle the Freon and need some special equipment. Got that?
I don't think any 134A units are available, but I sure could be wrong. Why are you interested in 134A?
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
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wrote:

Agreed.
You do, and if you are caught without it, working on your own stuff, one litttle vent thats seen by the guys that are paid to look for this stuff, and its a hefty fine...

There are none. 134A isnt used at all in central air units. R22, R12 (older ones) R500(old Carrier crap) R410a(the new R500 ). The reason he wants 134a is that he can still (currently, probably not for much longer) buy 134a at Wal-Mart without the proper EPA refrigerant handling certificate.

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Thanks for all the replies. Guess I'll stick with the window units. I did the calculations and need a 2.5 lb unit. The furnace air system will handle it. I installed that 5 years ago with plans for future central air. All new insulated ducting. A larger plenum so there will be plenty of room for the air handler. Wired to a heat and cool thermostat. I am interested in 134a because you don't need a license to use it. I have installed AC systems on several vehicles using it. It is available everywhere and easy to use.
wrote:

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Do it daily. Its not as simple as you might think. And what I am about to say, try to understand I make a ton of money on DIY kits, so dont think for a second I am trying to stop you..... First, ANY kit you buy will have the warranty void the second you install it. Thats right...in all technicalitys, its void the second you install it. Second, you wont know this till you call out a tech to find out why in a couple of years, why the compressors making this awful noise, and it wont cool, and they ask the important question..where is your invoice, and the techs name that installed it. You got it....every major maker of AC units clearly states that a non licenced person can not bring parts in for warranty.....gets better...if you buy it off the net, you have no place to go back to if you get a dud unit off the shelf. They dont have to make it right, since NONE of the major manufacters will allow their dealers to sell to the public directly off the internet. Its a fast way to get your dealership pulled.
Second, What size unit did your manual J call for? You stated you are getting AC, not a heat pump, so you didnt need to do a manual T. Too small a unit, you wont be happy..too large and you get cold, clammy air thats just wonderful for mold. Oh...that would also void the warranty, the part under improper installation.
Third, Now that you have your tonnage figured, and your airflow of the furnace you have is ok, and you have made sure that your furnace has the proper equipment to allow for AC additions on the unit, 2 speed fan and all, what does your manual D state about your current duct? Normally, straight heat duct is not large enough for AC. So, you will have to determine using the proper formula in manual D if your ducts are large enough to supply as many BTUs to each room and proper velocity of the air to each room to allow for proper cooling, and no air stagnation. Your return will normally have to be larger than it is as well, to maintain the proper face velocity depending on how much free area your current grille allows for.
Forth. Tools. You have all you need right? Starting with an EPA certificate that allows you to handle refrigerants. Not FREON, as Freon is nothing but a trademark name for any DuPont refrigerant. If you cant handle R22, or 410a, then you cant legally install the unit anyway. You have nitrogen for purging the lineset, and you have a good oxyacet tank set right? SilPhos? A micron gauge? A good vacuum pump to go with the micron gauge? A D_A_M_N good set of gauges, like CPS or the like? A Schrader core tool? All your Malco stuff? PErhaps you have ductboard, so you will be sure to insure that no fiberglass enters the airstream when you are done... After all that, you will need an EPA certified recover tank, and machine, JUST in case you overdo the charge when you get around to charging to superheat, or subcool, depending on the type of metering device you order. Anyone with any sense orders a TEV to put on the evap coil, since it will offer the best in making sure you are always getting what you pay for, and in the case of higher SEER units, it will allow you to gain all the SEER points you paid for.
Fifth: Lineset...you know where to put the oil traps if needed, and your pad will be the right thickness and size to code.
Sixth, Permits and inspections. In most areas, only a licenced and insured person can pull permits and ask for inspections, this may vary in your area.
7th- Electrical. You will need to insure that you have a new thermostat wire pulled from the furnace, to the thermostat, since you will more than likely have a 18-2 wire pulled, and will need at least an 18-5...perhaps more depending on the thermostat and options you add on.
8th- Allow me to suggest to you that you get someone that knows what he is doing, and has the needed tools on hand to insure that you get what you pay for.
Besides, you will be more than likely getting a Goodman unit, (Janitrol, or GMC...same stuff) and its garbage from the word go. Their warranty is clear...no licence, no warranty. Dont think you can not send in the warranty validation card and get away with it. EVERY make knows when the unit was last sold, and if you dont send the card in, the supplier is listed as still owning the unit, and since you have to have a licenced person fill out the back of their cards, well....again...no warranty.
Dont get me wrong. IF and only if you can get the right tools, know how to use them, can size your unit correctly to manual J, or T, and size your ducts to manual D...go for it. There is nothing like knowing you did it, and it works. But.. What really sucks is when you do it, and it works, but inst working right, and you dont know its not working right, and call someone like me out, and we find non condensables in the unit, or bubblegum welds that have allowed BBs to make their way to the metering device, and then, all that money you thought you saved is gone.
I personally LOVE DIY stuff. I HATE telling the person that warranty coverage has been denied, and that will be $1500 for the repair, and I have to notate that the ducts still undersized, and no further warranty on the part will exist after 7 days.
Seriously, (as all this has been) get someone thats licenced, and INSURED to run the unit. You might pay a bit more now, but you wont be paying later.

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Sounds like a racket.........but, I guess that's capitalism. I'm not knocking the HVAC guys but it seems like a form of price fixing. I know, liability, quality, blah blah blah. I know something about it, I'm somewhat close to the business (step father is). He mostly (not always) makes 100% on a unit plus his labor,and is STILL cheaper than most of the competitors! I say DIY! You just need to realize all the limitations to the job. Yes, in the long run it MIGHT cost you more, however, the satisfaction of knowing you did it yourself is awesome.
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'I say DIY! You just need to realize all the limitations to the job. Yes, in the long run it MIGHT cost you more, however, the satisfaction of knowing you did it yourself is awesome.'
ME: Not if you get hurt from mishandling the freon or the electrical. Plus...do you have a Vaccuum pump for properly dehydrating the system prior to start up and..do u know how to use it and know how many microns of vaccuum to pull down too and for how long to hold it there.?? Do u know how to charge a system properly so you dont cause damage to the compressor or undercharge the system so you dont cool correctly ? Do u understand the physics behind the refrigerant cycle for when it isnt performing correctly because you messed something up ?? Do u know how to properly solder for strong connections, how to install the cooling coil so you eliminate bypass air, and do u know all the local codes for the installation so when y ou go to sell your house...it doesnt get held up because it wasnt done in accordance to your village regulations ??
Save the 'DIY' approach for changing your oil, replacing a toilet, painting, and running an additional electrical outlet. You have no idea what you are getting into by doing a central air system. If youre going to still attempt doing it y ourself...then at least take a few courses at a local college at night so you really know what youre doing instead of winging it. The manufacturer and the seller of the DIY a/c system isnt going to warranty it if you install it or charge it up incorrectly and destroy something.
Dave
"Hey....have you hugged your Guage-Manifold today ?!"
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Not really...it is what happens when you have a trade that is regulated at the federal level. It is...contrary to popular belief...a tad harder than it looks...

How so? Price fixing would be what Goodman does...:) If you only knew..:) Oh hell..ok...every Goodman distributor has a 3% variance..thats all they have to work with. If a unit has a wholesale price of $1200, they have only 3% that they can go in either direction to sell it to the licenced contractor. The CONTRACTOR can sell it for what he wants.

The blah blah blah is what matters...all units are trash out of the box.
Not gonna rehash what you have heard before.

Then hes a crook..IMO. I have yet to mark up a unit that much...altho, you DO need to keep in mind that most everything you buy in the retail sector has been marked up that much, or more. I have one unit...that IMHO is the greatest thing to hit the market in years...really...but the wholesale price alone puts it so far out of the reach of most that I cant mark it up at all and sleep well.

IF and thats *IF* you know the CORRECT way to do it, or you will regret it.

Agreed.
Agreed, and I can tell you..if you hack one in, it WILL cost you more. Look...I make no appologies for my labor rate. None. When we find one that was screwed from the start, and its repaired, I can promise you its gonna cost more. Also what people fail to realize is that the better companies WILL charge more, and they WILL be around in a couple of years to continue service....its gotten to the point that the average man simply does not have a clue what it takes to keep an operation running..its much more than most expect.
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I DYI on most everything except furnace and AC installs. Shop around for a reasonable pro in your area. Do it right, suffer when you pay the bill and enjoy for many years.
Colbyt
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'I want to add central air to my existing forced air furnace. I see many available kits and it looks pretty straight forward. Any one done this? Also all the kits, I have seen, use Freon. Any one know of any that use 134A.'
ME: Clint Eastwood as Dirty Harry once said :' A man just has to know his limitations' .
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Yup, and in your case Davey, you have to be a man, and have to know something in order to know if you are capable...
So far, you miss on both counts..
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