Central AC

I'll be putting in the outside unit (condenser) at the rental tomorrow, the lines were cut back near the A coil, but there are a few inches to work with. I've never done this before.

The outside diameter line is .733" and .383", I'm thinking that must be 5/8 and 5/16, is that right, or is that 3/4, 3/8 OD?

What should I solder that with and what kind of coupling? I've got some Stay-Brite #8 (and a map torch). Will that work, or would something else be better or easier.

The outside unit is R22, Goodman CRT24-1A. Is that any good? The house is 900SF.

I suppose since the A coil is perhaps 15 years or so old, that it will be fine with that. Is that right?

I'll need to pick up some charging gauges, I have an old vacuum pump. I don't have a thermocouple temp gauge but I do have an IR thermometer and some old chemistry thermometers. I, of course, want to stay on this side of slugging the compressor. How should I go about charging this? I think this has an expansion valve (but am not positive), so that would be sub cooling.

Any hints or such? Pointers or resources?

What about R22a? Something else?

On another note, I have friend whose central AC hasn't worked for a couple years. Something funky where they have to rewire it for either heat or AC. Not much money there and she had someone out to look at it who said it was $200 job. Might as well have been $2,000.

So I had a look at this, the furnace is in the attic, man it was hot up there! No voltage at the thermostat. The thermostat wires went to a board with two relays on that with wires running out to the outside unit and some other wires that were not quite hooked up to the furnace board, a couple inches short of being screwed down. I suppose that is a $200 repair...

Jeff

Reply to
Jeff Thies
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You might try taking the HVAC course at your local community college or trade school first. :-)

TDD

Reply to
The Daring Dufas

Thanks, I'll do that first thing in the morning! ;-)

Jeff

Reply to
Jeff Thies

Sorry man, but this is one where you are in over your head...

EPA requires a license to buy refrigerant to charge the system, the supply house WILL NOT

Reply to
Evan

Call a pro, you are in over your head already. Do you have a vacuum pump? Do you know how to evacuate the system? Do you have a license to buy the refrigerant?

Reply to
Ed Pawlowski

Yes, it's in the post. It's an old RobinAir monster.

Do you know how to evacuate the system?

Of course.

Do you have a license to

Yes. Have had for years.

I've just never done it. I've done auto air, but of course the oiling, pump et all are different. I have no real problem with the concepts, with an expansion valve unit you are setting the subcooling to make sure it is all liquid going into the expansion valve. I think on my unit it is 12F of SC. Superheat should be constant. You just read the temp off a PT chart and see where you are from actual.

I figured this would be easy. I'm sure it was all working before the outside unit got stolen, so it doesn't need to be flushed. It's only 6' to the evaporator, so no adjustments or oil traps needed. The system is empty, so no recovery needed. The furnace end is fine, so no worries about the duct work and blower. I figure 2 tons is enough. It's not like I want to go in the HVAC business. I just want to get AC in.

Obviously everyone thinks I'm in over my head, but I'm not uncomfortable with being there. I used to think you needed a pro to rebuild an automatic transmission or an engine, and those weren't hard.

Is there something that makes this so difficult that I'm missing? Do I really need a pro?

Now plumbing, that's hard.

Jeff

Reply to
Jeff Thies

Given those measurements, I'd bet the line size you have is 3/4" and

3/8" which are very common. Regarding the joining method, if you goodle a bit you'll find lots of debate on the subject. The pros mostly braze, but there are some that use #8 and swear by it.

The folks who make the Silverbrite #8 have done demonstrations where they put both an AC braze joint and a joint soldered using #8 under test pressure until they burst. The brazed joints always fail first, at a lower pressure, because the high brazing temp weakens the copper. So while the braze alloy itself is stronger, the net result is #8 performs better.

The other MAJOR issue is if you braze, you need to have the lines filled with nitrogen to prevent oxidation from taking place and producing crud inside the lines. Which presents yet another problem for the DIY. With #8 and the lower temps, that doesn't happen, at least not to the extent that it's a problem. Personally, I'd use the #8.

However, all in all, you may be better off just hiring someone with all the right eqpt to do the job. Especially since it's a rental and tax deductible.

Reply to
trader4

There are so many things wrong with this picture.... The OP doesn't have a clue, and will be really lucky to get either system running, and there is no way on GODs green earth he is going to get it right.

By the time he gets done, and then has to call a *competent* tech to straighten out the mess, its going to cost way more than if he had hired a licensed, insured, bonded, professionally trained, Master Technician to replace the entire system in the first place.

Reply to
Steve

Reply to
.p.jm.

Are you guys AC professionals or wimps?

Jeff

Reply to
Jeff Thies

#8 it is. I've soldered up 1" hard copper with this so I think I can do up the smaller stuff.

$500 seems to be the price for almost anything, except hooking up thermostat wires which is $200. I'm resistant to that.

I may track down an old buddy to fill it or I may just try it myself. I figure I'll check the superheat on the way up to see if there is a fault somewhere. With a THX I can't see where I can really damage anything.

I'll bolt in the unit today. Bought some 10" 1/2" bolts to go through the block wall foundation and a 2 x 4. Have some stout angle stock to bolt on that and rest on the top edges of the unit. Some snake eye screws into the cover and I think that will be enough to discourage the AC recycling business. When I was looking at houses I saw exactly one that still had the outdoor unit. Cages don't seem to be much of a deterrent.

Thanks, Jeff

Reply to
Jeff Thies

Consider adding a phony (or maybe real) security camera high up on the wall. Harbor Freight and others have some that look very authentic. Some wire strung around the perimeter on BIG insulators might work, too.

Joe

Reply to
Joe

Jeff is a smart fellow, he has the skill set but lacks experience in the trade. I was working on a long post last night before my body ran out of steam (just started on antibiotics to head off walking pneumonia) and could not finish it. I was listing all the things he would need to do in order to piece together the condenser, line set and evaporator because I do that kind of thing with used often disparate equipment all the time. I can make it work and it keeps on working. Me and my friend GB help out a lot of organizations and people who don't have a lot of money so we deal in used stuff quite often. Steve, you have a heck of a business and I admire you for it but there are a lot of good people out there who can't afford new equipment and premium prices for service and repair so they call us. Jeff can't help but learn a great deal from his perilous adventure so he will make out either way. Besides, it's great entertainment. ^_^

TDD

Reply to
The Daring Dufas

I think you have the right idea. Use silver solder if you can on the refrigerant lines. Make sure the A coil and compressor match up, the expansion valve in the A coil that is. Pressure test it with air first if everything holds suck it dry and charge it up. Then come back and tell us how easy it was and how much you saved. If you see the code enforcement truck drive by be sure to wave. A penny save is a penny earned. I probably left a few things out but you seem to have the right idea, now get to work.

Reply to
FatterDumber& Happier Moe

Its the landlords responsibility to make sure the comfort system is working properly.... Sure it might cost him a couple of months rent to get it done right, but its the cost of doing business, and he should have funds set aside to cover these type of evolutions.

Its the same as any other business owner. That being said, he doesn't have to shop for the most expensive tech in the book, nor should he shop for the cheapest(as landlords are known to do). He should shop for one who is going to do it right, pull the appropriate permits, have the appropriate inspections done, and guarantee his/her work.

Reply to
Steve

Thanks!

It's taken all day to get the parts. I finally found the 3/4" line, ran me $10 used!

I'll get this started tonight and pick up the gauges tomorrow. In the meantime I'll look back through "Refrigeration & Air Conditioning Technology 5th Edition". Not all 1324 pages, of course!

Jeff

Reply to
Jeff Thies

I sometimes like to try doing things on my own -- partly just for the fun and adventure of it, and partly as a way of learning how various projects are done. This one, however, would be WAY out of my league. You're a brave soul for trying this one even if you do have automotive AC experience etc.

Since it's a rental property (meaning you are a landlord/investor), have you considered seeing if there are any "REIA's" (Real Estate Investor Associations) near you that you could join? I own some rental properties and belong to a REIA where I am located and one located in the State next door. By being a member of both, I can easily post questions to fellow members about where to find a reasonable HVAC person who may be willing to do a slightly unusual but small job like this at a reasonable cost. If you mention where you are located, I could check to see if I could find a REIA near you. Or, you could check some websites like this one:

formatting link
You wrote yesterday that you'll be trying this today. Did you try ityet?Jeff Thies wrote:> I'll be putting in the outside unit (condenser) at the rental> tomorrow, the lines were cut back near the A coil, but there are a few> inches to work with. I've never done this before.>> The outside diameter line is .733" and .383", I'm thinking that must> be 5/8 and 5/16, is that right, or is that 3/4, 3/8 OD?>> What should I solder that with and what kind of coupling? I've got> some Stay-Brite #8 (and a map torch). Will that work, or would> something else be better or easier.>> The outside unit is R22, Goodman CRT24-1A. Is that any good? The> house is 900SF.>> I suppose since the A coil is perhaps 15 years or so old, that it> will be fine with that. Is that right?>>

I'll need to pick up some charging gauges, I have an old vacuum> pump. I don't have a thermocouple temp gauge but I do have an IR> thermometer and some old chemistry thermometers. I, of course, want> to stay on this side of slugging the compressor. How should I go> about charging this? I think this has an expansion valve (but am not> positive), so that would be sub cooling.>> Any hints or such? Pointers or resources?>> What about R22a? Something else?>> On another note, I have friend whose central AC hasn't worked for a> couple years. Something funky where they have to rewire it for either> heat or AC. Not much money there and she had someone out to look at it> who said it was $200 job. Might as well have been $2,000.>> So I had a look at this, the furnace is in the attic, man it was hot> up there! No voltage at the thermostat. The thermostat wires went to a> board with two relays on that with wires running out to the outside> unit and some other wires that were not quite hooked up to the>

furnace board, a couple inches short of being screwed down. I suppose> that is a $200 repair...>> Jeff

Reply to
RogerT

Oops, my last post didn't come out correctly. Here's a re-write:

I sometimes like to try doing things on my own -- partly just for the fun and adventure of it, and partly as a way of learning how various projects are done. This one, however, would be WAY out of my league. You're a brave soul for trying this one even if you do have automotive AC experience etc.

Since it's a rental property (meaning you are a landlord/investor), have you considered seeing if there are any "REIA's" (Real Estate Investor Associations) near you that you could join? I own some rental properties and belong to a REIA where I am located and one located in the State next door. By being a member of both, I can easily post questions to fellow members about where to find a reasonable HVAC person who may be willing to do a slightly unusual but small job like this at a reasonable cost. If you mention where you are located, I could check to see if I could find a REIA near you. Or, you could check some websites like this one:

formatting link
.

Good luck.

P.S. You wrote yesterday that you were going to try this project today. Did you get to try it yet?

Reply to
RogerT

That's a LITTLE harsh! Don't you think?

The knock you hear on your door will be the Secret Service.

Reply to
HeyBub

He could get lucky. . .

Or study up at Wikipedia. . .

Reply to
HeyBub

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