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Discussion Starter · #1 ·
Howdy folks, I just joined the forum. I'm replacing an old Fraser-Johnson AC unit in my 1962 Ranch home. I'm planning on doing it myself as I do everything else. I have done some automotive AC work and have guages and a vacuum pump. I installed the furnace myself in 93.

I'm just starting to research this. Mine is a split system with the evap coil attached to the furnace. The furnace works fine and doesn't need replaced. My furnace manual says it can handle 4 ton with the blower motor set to high.

I got an estimate locally for a Trane system installed for $4800. We don't use either the furnace or AC that much since we have a fireplace with blower and ceiling fans with window shutters.

Are there any previous threads on this forum I can look at that would cover replacing an AC system or sizing a system, etc. that I should look at before bombarding the forum with questions? I searched on AC install or replace and got a zillion hits. Thanks.
 

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HVAC CALC

Use this for sizing.
DON"T fudge. Use the actual temps for your area, and the temp you will be setting your stat at.

Do both the heating and cooling loads.
See how far off your furnace sizing was.
 

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Replacing 47 year old AC unit

Thank goodness for planned obsolescence:laughing:
 

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Ols system

If your old system when working kept the house comfortable I would try to find out what BTU rating / tonnage the old system was and install same size unit.
Of course with a high seer rating.
The Trane install sounded pretty good.
 

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$4800 what a scam, for a weekends worth of work and $1000 in equipment. well you know home depot pockets half and subs the rest out.

My dad does HVAC for a living and I wish I would have learned more about, I've done dozens of installs but never got involved in sizing.

what's your sqft?
 

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Home depot gets 10 to 15%.
The salesman in HD work for a Trane dealer, not HD.


Majority of systems put in 47 years ago. Were oversized when they were put in.

And if any improvements have been made to the envelope or insulation.
Then its oversized that much more.
 

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Discussion Starter · #8 ·
The old system was so old that they couldn't check model number to determine the rating/tonnage I think they said when they gave me the estimate. I'm a little leery since the owner said he doesn't provide written estimates. Although they have done some good repair work for us over the years.

After looking at this forum and some links about sizing I'm not sure about the sizing. I'm sure he did the "rule of thumb" sizing. All he did was ask me the square footage of the house and how long we would be here. He did look at the furnace though since I said it didn't need replaced and it was rated 4 ton with motor on high.

Also, we keep our house at 65 in the winter, 62 when we're not home with programmable stat. When home we usually have the fireplace going. In summer we open all shutters and windows at night. In morning we shut all shutters and curtains and windows and turn on ceiling fans.

We live near Sacramento CA and sometimes it gets 105+ in the summer. When we get more than one day of 100+ we use the AC and leave it on but at 75. So maybe sizing isn't critical for us. But in 15 years when I'm 67 that may all change.

Also, we're sticking with R22 so no line change or flush.
 

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Discussion Starter · #10 ·
Originally, it had all electric heat. We couldn't afford the bill so we replaced with gas unit. The single pane windows were whistling with the wind. Insulation was minimal and missing on alot of places. There was no sheathing just wafer board siding. So I replaced all that. Pretty airtight now.

But then it usually doesn't get colder than 45 most of the winter. Though sometimes down in the 20's.
 

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$4800 what a scam, for a weekends worth of work and $1000 in equipment. well you know home depot pockets half and subs the rest out.

Like been said .. The Trane dealer in H.D. Is who you are buying from .. Not H.D. How do you know $4800 is a scam.. Do you know the going rate for his area , over head, insurance rates, how much work is involved for this job,etc,,, ???
 

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Discussion Starter · #13 ·
Oh, I'm not saying it's a scam. It may be a fair price. I just decided to do as much of the work as possible myself to save money. Also, I want to learn more about HVAC so I can do repairs myself as much as possible. I'd like to pay them for things I probaly can't do or don't want to do like reclaiming the R22 and soldering the connections and building any sheet metal transitions or plenum, etc.

Plus I have a relative who works for a wholesaler that would be upset if I didn't buy from him at his cost for the hardware.

I can put the unit in and hook up existing wiring and add a disconnect box outside, etc. If I can save a couple grand and give him some work we should all be happy.
 

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Like been said .. The Trane dealer in H.D. Is who you are buying from .. Not H.D. How do you know $4800 is a scam.. Do you know the going rate for his area , over head, insurance rates, how much work is involved for this job,etc,,, ???
I'm sure many people pay prices like that for all kinds of jobs, but like they say a fool and their money are soon parted.

I don't care what your """overhead""" is, I don't want to pay for your fancy decal'd new pickups and for some guy to harass me at home depot to get a new furnace. especially now that times are so tough.

I'd like to pay them for things I probaly can't do or don't want to do like reclaiming the R22 and soldering the connections and building any sheet metal transitions or plenum, etc.
That's 99% of the install :)
 

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Been to H.D many times .. Never been harrassed by anyone :no: Over head don't just mean trucks.. It's insurance for when your house burns down, It's workmans comp. When he gets hurt on your property, It's tools to do the job right, it's CEC'S It's HVAC classes,, ETC,
 

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I don't care what your """overhead""" is, I don't want to pay for your fancy decal'd new pickups and for some guy to harass me at home depot to get a new furnace. especially now that times are so tough.
What do you do.
So we know what to get cheaper.
Cause we don't want to pay for your house. :laughing:
 

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$4800 what a scam, for a weekends worth of work and $1000 in equipment. well you know home depot pockets half and subs the rest out.

My dad does HVAC for a living and I wish I would have learned more about, I've done dozens of installs but never got involved in sizing.

what's your sqft?
I would suggest you watch who you insult with words like SCAM.

Most of the "Free answers" from this site are given by pros in the business for a long time and know a whole lot more then you.

Since we don't get paid to give free advice you slight of our industry is even more blatant.

So clam up with the insults.


Oh, and why ask the guys square footage? You gonna do a free Manual J load calc for him?
 

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Let' make a deal

$4800 what a scam, for a weekends worth of work and $1000 in equipment. well you know home depot pockets half and subs the rest out.

My dad does HVAC for a living and I wish I would have learned more about, I've done dozens of installs but never got involved in sizing.

what's your sqft?
johnny boy
I have an empty warehouse, I do not know what size equipment cable-data-guy needs, however I will give you 1K for every complete system you have to fill my warehouse. You got to be kidding. :confused1:
 

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Discussion Starter · #19 ·
I've been looking at a bunch of threads and links through this site.

What I've learned so far is that I need to do a system sizing calc for heating and coling before jumping in and buying a system from my cousin.

I guess I forgot to mention my house is 2400 sq ft. In summer humidity is almost zero.

Once I size the system and get it here I'll need to do these steps if only need new AC.

1. Pull out the old R22.
2. Pull out the old system. It's in the attic and will come down the ladder.
3. Make sure I plug all the lines good to keep air/moisture out.
4. Put the new system in place. Push it up the ladder
5. I need to build a new pad for my outside unit.
6. I need to put in a disconnect box at the outside unit.
7. Hook up the wiring.
8. Attach all the lines soldering the joints.
9. Put in a receiver/drier in liquid line to evap.
10. Get a transition box built for furnace to coil. My furnace manual says it must be 18" long.
11. Will need a new plenum box built and attach ducts to it.
12. Pull a vacuum on the system. Leave it overnight to see if it holds.
13. Recharge with R22.
14. Fire it up and see if it works.

What am I missing?

While I have the plenum removed should I have the ducts all cleaned out?
 

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What size breaker/ wire will the new unit require ??. I test with nitrogen & pull system down to within 200 microns. I also purge with small amount of nitrogen while soldering
 
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