On Tuesday, May 6, 2014 6:28:55 PM UTC-4, Terry Coombs wrote:
sms wrote:

I've been getting quotes for central A/C and they all seem very high.



The basic components are available to me at the following prices:



Air Conditioning Condensing Unit Horizontal Discharge, 13 SEER,

Single-Phase, 2 Ton, R410A $1300



Evaporator: $230



Replacement furnace: $550



So the big items are about $2300 including tax. The quotes I've been

getting are around $7000.



I don't really need a new furnace, but the existing one is about 32

years old and it's so tall that to install the A/C would require a lot

of duct work to fit in the evaporator, while with a new, shorter

furnace, there is no duct work needed.



The 230V power and all the plumbing are already in place. The

electrical panel needs a circuit breaker connected to the 230V wiring

that's coiled up behind it. I need to change the furnace blower motor

from plug-in to hard-wired with a switch, which is easy to do.



Has anyone here done their own A/C install?



I did mine about 12-13 years ago , replaced the furnace and added AC .

Second summer it didn't cool too well , because I had a leak in a fitting on

the LP side tubing . Fixed that and recharged and the only problem since was

a blown S/R cap in the condenser unit - and my son replaced the supply

breaker recently because it went bad .

I did have prior experience with refr work Dad did AC/R , metal work ,

and electrical ...

--

Snag

I replaced my gas furnace and AC 3 years ago. I did a lot of research
first and I didn't run into anything really unexpected. Like many
things, it's more work than you would think. It was about $4000 for
the eqpt for a 5 ton AC, 120K BTU furnace.

Some answers and comments:

To do the brazing of the copper lines, you need to flow nitrogen through
the system, otherwise the high temps will cause oxidation and you'll
have crud inside the new system.There are alleged "pros" out there that will skip that step, but if you want to have a system that fails prematurely,
the choice is yours. In retrospect, if I had to do it all over again,
instead of brazing, I'd use Staybrite 8, which is solder with silver
added. If you do some research, you'll see pros bitching back and forth
about whether it's OK or not. There are plenty that have used it for
decades. Also, if you google, you'll find a Harris Products video that
shows what happens when you braze fittings versus use the Siverbrite 8.
While people believe brazing is stronger, there is more to it than that.
The joint itself is stronger with brazing, but the high heat affects the
soft copper tubing. Harris shows videos of where they pressure test both
methods to the failure point. The brazed tubing fails first, bursting
near the joint. The Staybrite stays intact to higher pressures. If you
use Staybrite, you can probably skip the nitrogen because the temps
required for soldering are much lower than brazing, so it's unlikely
that crud is going to form.

The system comes pre-charged, with enough refrigerant for a given length
of lines. If your lines are about the right length, it should not need
additional charge. But it does need to be evacuated with a vacuum pump
prior to opening the valves. Doing that right is critical. So, it's more practical to get someone to
do that portion of the job. I found a guy on Craigslist, and of course
anytime you're dealing that way there is some risk. I had longer lines,
so he had to top it off too.

You're almost certainly not going to wind up with a warranty that will
be honored by the manufacturer. But I'm 3 years in and it's all working
A-OK.

And I'd look into state, utility, etc rebates. I got the fed tax credit,
but no state/utility rebates. The state/utility rebates required information
and processes that you couldn't complete yourself, at least not easily.
For example, they required a complete manual J calculation, so I just
said to hell with it. I still saved several thousand dollars. But it's
worth making the true price comparison, including any rebates that you could
get if you do it via a contractor.

Also, you probably need to pull permits, depending on where you live.
I had to pull three here in NJ.