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cable_data_guy 04-09-2009 03:12 PM

Replacing 47 year old AC unit
 
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.

beenthere 04-09-2009 04:37 PM

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.

cable_data_guy 04-09-2009 04:45 PM

Thx, I'll check it out.

Home Air Direct 04-09-2009 05:12 PM

Replacing 47 year old AC unit

Thank goodness for planned obsolescence:laughing:

SULTINI 04-09-2009 06:03 PM

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.

johnnyboy 04-09-2009 06:03 PM

$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?

beenthere 04-09-2009 06:07 PM

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.

cable_data_guy 04-09-2009 06:18 PM

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.

kenmac 04-09-2009 06:24 PM

Going to leave the old Evap. coil ? You will get better results ( heat & A/C ) with a matched system

cable_data_guy 04-09-2009 06:26 PM

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.

cable_data_guy 04-09-2009 06:29 PM

Yes, replacing the evap coil and outside unit.

kenmac 04-09-2009 06:33 PM

Quote:

Originally Posted by johnnyboy (Post 257508)
$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,,, ???

cable_data_guy 04-09-2009 06:48 PM

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.

johnnyboy 04-09-2009 08:23 PM

Quote:

Originally Posted by kenmac (Post 257527)
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.

Quote:

Originally Posted by cable_data_guy (Post 257532)
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 :)

kenmac 04-09-2009 08:35 PM

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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