I'm closing in a room that has a chase located next to the chimney. I
want to run lines for a future central air system while the wall is
open. There's a crawl space below, marginal access on the second floor
and good access in the attic where the air handler will be located. I
picked up a 50' 3/4" & 3/8" line set which will work with the
anticipated 2 or 2.5 ton 2nd floor load.

My questions:
- I don't see how I'll be able to run the line without having at least
one or two cuts/couplings. I've read silver brazing is better than
sweating the joints. How critical is the difference?

- Is flux a problem with making connections in a refrigerant line?
Alternatives?

- I'll be pulling a 12/3 line for the unit and to provide an additional
circuit in the attic. What wire should I pull for the AC controls?

- I've never pulled such a large line. With electrical I use a fish
tape. Can I use that to help pull the insulated copper? Any tricks to
keep the insulation from hanging up and getting ripped?

Thanks.

R

"RicodJour" wrote in message
oups.com...
I'm closing in a room that has a chase located next to the
chimney. I
want to run lines for a future central air system while the
wall is
open. There's a crawl space below, marginal access on the
second floor
and good access in the attic where the air handler will be
located.


If its not a stand up attic with stair step access (not a
ladder) your repair guy will hate your guts... not to worry
about him though, he will just all the grief to your
bill...with a smile.





I
picked up a 50' 3/4" & 3/8" line set which will work with
the
anticipated 2 or 2.5 ton 2nd floor load.

yes that works



My questions:
- I don't see how I'll be able to run the line without
having at least
one or two cuts/couplings. I've read silver brazing is
better than
sweating the joints. How critical is the difference?

Best by a massive margin is run it without any cuts
solders or brazing..those cause oxide inside the tube and that
oxide seeds nasty chemistry into your system and shortens its
life significantly..if you do braze run a dry nitrogen purge
through the line when you do it.... 15% silver brazing rod is
best, called silflos in most stores is best, you need an oxy
actytlene torch for that.. over 1500 degrees to work well.

dont flux the joint, the acid gets into the tube that way
and seeds bad chemistry in the operating system.


- Is flux a problem with making connections in a refrigerant
line?
Alternatives?

Use an oxy/ actylene flame, get it neutral, then open the
oxygen valve slightly to get a faint 'feather' on the
flame..test it on a tarnished penny... when its right the
penny will turn bright copper under the flame..if its wrong it
will darken or soot will show up...


- I'll be pulling a 12/3 line for the unit and to provide an
additional
circuit in the attic. What wire should I pull for the AC
controls?

Run 10-2 with a ground... you dont need 3 conductors for a
single phase system...you will get about 2% less voltage drop
on a hot day when the voltage is low anyway... 12/2 would work
though for 2.5 tons but its skimping. (the charts are
irrelevant to whats best for your system, the charts are for
fire safely purposes, the NEC is part of the national fire
code)




- I've never pulled such a large line. With electrical I
use a fish
tape. Can I use that to help pull the insulated copper?
Any tricks to
keep the insulation from hanging up and getting ripped?


In buildings less than 3 stories you dont need conduit inside
the walls... for ac in those cases run romex. where it goes
outside run the romex into a box..then run rain tight conduit
outside to the condensing unit etc.

Phil Scott
Mech/ Electrical contractor since 1210...



Thanks.

R

"Phil Scott" wrote in message
...

"RicodJour" wrote in message
oups.com...
I'm closing in a room that has a chase located next to the
chimney. I
want to run lines for a future central air system while the
wall is
open. There's a crawl space below, marginal access on the
second floor
and good access in the attic where the air handler will be
located.


If its not a stand up attic with stair step access (not a
ladder) your repair guy will hate your guts... not to worry
about him though, he will just all the grief to your
bill...with a smile.





I
picked up a 50' 3/4" & 3/8" line set which will work with
the
anticipated 2 or 2.5 ton 2nd floor load.

yes that works

PS... one caveat.. best is to avoid soldering. the 2
ton unit will have a 5/8" suction line probably and a 1/4"
liquid line. so if there is a miss match you will have to
solder.

also if the evaporator coil is above the condensing unit the
fat suction line you are showing will work just fine, and
advantage actually... if the air handler / coil is below the
condensing unit, the fat suction line can pose 'oil return'
problems if its much of a rise... if thats the case bend a
slight trap into the bottom of the riser on the larger line.
a riser over 10' should be avoided.. especially if you end up
with an oversize suction line as you are showing in the event
of the 2 ton unit (size also dependent on the efficiency of
the unit, check all that out...with the smaller unit, which
should be fine the 5/8" suction line is a lot easier to bend,.
you can avoid all the soldering.

bending trick,, try to arrange bends to match the way the tube
is already coiled...bending it sideways or backwards is more
difficult.. you can rent a lever arm tube bender for that
though.

Phil Scott






My questions:
- I don't see how I'll be able to run the line without
having at least
one or two cuts/couplings. I've read silver brazing is
better than
sweating the joints. How critical is the difference?

Best by a massive margin is run it without any cuts
solders or brazing..those cause oxide inside the tube and
that oxide seeds nasty chemistry into your system and
shortens its life significantly..if you do braze run a dry
nitrogen purge through the line when you do it.... 15%
silver brazing rod is best, called silflos in most stores is
best, you need an oxy actytlene torch for that.. over 1500
degrees to work well.

dont flux the joint, the acid gets into the tube that way
and seeds bad chemistry in the operating system.


- Is flux a problem with making connections in a
refrigerant line?
Alternatives?

Use an oxy/ actylene flame, get it neutral, then open the
oxygen valve slightly to get a faint 'feather' on the
flame..test it on a tarnished penny... when its right the
penny will turn bright copper under the flame..if its wrong
it will darken or soot will show up...


- I'll be pulling a 12/3 line for the unit and to provide
an additional
circuit in the attic. What wire should I pull for the AC
controls?

Run 10-2 with a ground... you dont need 3 conductors for a
single phase system...you will get about 2% less voltage
drop on a hot day when the voltage is low anyway... 12/2
would work though for 2.5 tons but its skimping. (the charts
are irrelevant to whats best for your system, the charts are
for fire safely purposes, the NEC is part of the national
fire code)




- I've never pulled such a large line. With electrical I
use a fish
tape. Can I use that to help pull the insulated copper?
Any tricks to
keep the insulation from hanging up and getting ripped?


In buildings less than 3 stories you dont need conduit
inside the walls... for ac in those cases run romex. where
it goes outside run the romex into a box..then run rain
tight conduit outside to the condensing unit etc.

Phil Scott
Mech/ Electrical contractor since 1210...



Thanks.

R

"RicodJour" wrote in message
oups.com...
I'm closing in a room that has a chase located next to the
chimney. I
want to run lines for a future central air system while the
wall is
open. There's a crawl space below, marginal access on the
second floor
and good access in the attic where the air handler will be
located. I
picked up a 50' 3/4" & 3/8" line set which will work with
the
anticipated 2 or 2.5 ton 2nd floor load.

My questions:
- I don't see how I'll be able to run the line without
having at least
one or two cuts/couplings. I've read silver brazing is
better than
sweating the joints. How critical is the difference?

- Is flux a problem with making connections in a refrigerant
line?
Alternatives?

- I'll be pulling a 12/3 line for the unit and to provide an
additional
circuit in the attic. What wire should I pull for the AC
controls?

- I've never pulled such a large line. With electrical I
use a fish
tape. Can I use that to help pull the insulated copper?
Any tricks to
keep the insulation from hanging up and getting ripped?

Thanks.

R


More on soldering... some units have tube connections that
must be soldered.. the hot set up for that is 'stay bright
silver solder' the kind I am talking about is available only
at refrigeration wholesale houses as a rul, it comes in a
roll, has a silver content, is soft, and needs the matching
flux, it melts and flows very well at 400 degrees or so...all
that tends to preclude oxidizing the inside of the tube...its
very strong and wont corrode with age...it flows well.


If you go that route, sand the tube with the sand cloth you
buy at the refrig wholesalers, other sand cloth has resins on
it that screw things up totally... then wipe the flux onto the
tube end and fitting with a paper towel, leave no excess.. fit
then solder..that works great..dont over do it.. heat the
fitting not the tube. a propane torch is good for that. you
can avoid the use of dry nitrogen that way.

then if you need need air purge directions for the fit up tube
post on that issue... it should be covered in the directions
or they are advising you to use a vacuum pump to get the air
out of the lines before you open you new line set to the
system. thats important.



Phil Scott

"RicodJour" wrote in message
oups.com...
I'm closing in a room that has a chase located next to the chimney. I
want to run lines for a future central air system while the wall is
open. There's a crawl space below, marginal access on the second floor
and good access in the attic where the air handler will be located. I
picked up a 50' 3/4" & 3/8" line set which will work with the
anticipated 2 or 2.5 ton 2nd floor load.

My questions:
- I don't see how I'll be able to run the line without having at least
one or two cuts/couplings. I've read silver brazing is better than
sweating the joints. How critical is the difference?

- Is flux a problem with making connections in a refrigerant line?
Alternatives?

- I'll be pulling a 12/3 line for the unit and to provide an additional
circuit in the attic. What wire should I pull for the AC controls?

- I've never pulled such a large line. With electrical I use a fish
tape. Can I use that to help pull the insulated copper? Any tricks to
keep the insulation from hanging up and getting ripped?

Thanks.

R

The diameter of the pipe is dependant on DISTANCE and tonnage. You estimate
the tonnage, but what about the distance? Call someone in your area and get
a quote for the a/c. And what size of lines they would run.
I insulate after installing and all silver soldering is finished and a
vacuum verifies all is well.
I use mule tape and AT LEAST one other person to pull in the line set.
Harder situations some time it is 2-3 other guys for a short period of time.
I work to NOT have couplings in the lines.

Why run 12 -3? You do not need a neutral for a condenser and most air
handlers. Are you sure 12 is big enough?
Controls are dependant on what your doing. High end stuff I do I use 9-12
wire, never less than 7 wire for the controls. Way to easy to have more than
enough than less. But then again I buy control wire on 1000 foot spools.

Soldering WILL get ya in trouble maybe not right away but it will fail.
Silver solder is the only way to do it correctly. Also the ends need to be
welded shut.

Phil Scott wrote:
"Phil Scott" wrote in message
"RicodJour" wrote in message

I'm closing in a room that has a chase located next to the
chimney. I
want to run lines for a future central air system while the
wall is
open. There's a crawl space below, marginal access on the
second floor
and good access in the attic where the air handler will be
located.


If its not a stand up attic with stair step access (not a
ladder) your repair guy will hate your guts... not to worry
about him though, he will just all the grief to your
bill...with a smile.

Hey Phil. If I run the refrigerant and power/controls lines so it's
all ready to go for him, that should make him smile, too. The attic is
technically a stand up with a flight of twist stairs to get you up to
the third floor/attic. Unfortunately the attic storage space will all
go bye bye when the evaporator and ductwork are installed.

I picked up a 50' 3/4" & 3/8" line set which will work with
the
anticipated 2 or 2.5 ton 2nd floor load.

yes that works

PS... one caveat.. best is to avoid soldering. the 2
ton unit will have a 5/8" suction line probably and a 1/4"
liquid line. so if there is a miss match you will have to
solder.

There has to be soldering at the ends in any event, right? The
nitrogen purge (sounds like a visit to the proctologist) with the
meticulous soldering/brazing seems a little involved. Can the
connections be done another way? Flare fitting perhaps?

also if the evaporator coil is above the condensing unit the
fat suction line you are showing will work just fine, an
advantage actually

Okay, sounds good. Why an advantage?

if the air handler / coil is below the
condensing unit, the fat suction line can pose 'oil return'
problems if its much of a rise... if thats the case bend a
slight trap into the bottom of the riser on the larger line.

It's not, so no problem.

a riser over 10' should be avoided.. especially if you end up
with an oversize suction line as you are showing in the event
of the 2 ton unit (size also dependent on the efficiency of
the unit, check all that out...with the smaller unit, which
should be fine the 5/8" suction line is a lot easier to bend,.
you can avoid all the soldering.

Have the 3/4", opened the box, rather not return it. So it sounds like
for a smaller unit, 2 tons, the 5/8" is preferred, but the 3/4" is an
advantage (to be specified). Net plus or minus?

bending trick,, try to arrange bends to match the way the tube
is already coiled...bending it sideways or backwards is more
difficult.. you can rent a lever arm tube bender for that
though.

I have a bender floating around somewhere. It's just a question of
finding it at the right time. It looks like I'll need at least three,
maybe four people to pull that line in one piece, assuming I can cut
adequate holes in some tight locations.

I should make it clear that it's very doubtful that I'd be doing the
system installation, so I'm not looking to make more work for myself.
I'll hire a contractor in a few months or few years when the project
goes ahead and let him worry about all of the connections and such.
The driving force is my desire to not have to open up walls down the
road. I hate cutting into my own work. Really.

So with that in mind, can I just cut the line set, pull two sections
and leave access to the mating ends for the sub's connection a few
months from now?

Is there a specialized cap of some sort to facilitate pulling of the
line set? Is there something like a Fernco fitting with a loop in the
end to which the pulling line could be attached? I'm concerned that
I'll rip the crap out of the insulation as I'm pulling the line.

BTW, I could link you to some pictures of the project, 3D CAD files, if
you're interested.

thanks again

R

SQLit wrote:
"RicodJour" wrote in message

I'm closing in a room that has a chase located next to the chimney. I
want to run lines for a future central air system while the wall is
open. There's a crawl space below, marginal access on the second floor
and good access in the attic where the air handler will be located. I
picked up a 50' 3/4" & 3/8" line set which will work with the
anticipated 2 or 2.5 ton 2nd floor load.

My questions:
- I don't see how I'll be able to run the line without having at least
one or two cuts/couplings. I've read silver brazing is better than
sweating the joints. How critical is the difference?

- Is flux a problem with making connections in a refrigerant line?
Alternatives?

- I'll be pulling a 12/3 line for the unit and to provide an additional
circuit in the attic. What wire should I pull for the AC controls?

- I've never pulled such a large line. With electrical I use a fish
tape. Can I use that to help pull the insulated copper? Any tricks to
keep the insulation from hanging up and getting ripped?

Thanks.

R

The diameter of the pipe is dependant on DISTANCE and tonnage. You estimate
the tonnage, but what about the distance? Call someone in your area and get
a quote for the a/c. And what size of lines they would run.

I have gotten some estimates, and received much conflicting advice as
to whether the high velocity systems would work in this particular
house. The load estimates (no calculations were done) were in line, so
that's where the tonnage came from. The distance I alluded to (sorry,
should have spelled it out) was the 50' lineset. It's going to be
right in that ballpark, a few feet shorter at the most.

I insulate after installing and all silver soldering is finished and a
vacuum verifies all is well.

I can see the advantage to doing it that way. Unfortunately access
would make insulating the line almost as difficult as pulling it.

I use mule tape and AT LEAST one other person to pull in the line set.
Harder situations some time it is 2-3 other guys for a short period of time.
I work to NOT have couplings in the lines.

I can see the obvious advantage and would love to have an unbroken line
for a bunch or reasons. However, the route this line takes, while
fairly direct and with only two turns, is beyond tight. It seems that
pulling the line set down from the attic will be the easiest as I can
lay out a fairly long stretch to start to straighten it.

Why run 12 -3? You do not need a neutral for a condenser and most air
handlers. Are you sure 12 is big enough?

Not any more. My electrician said the 12 was fine, that most units are
110 now, and it wouldn't be a problem. I'll look into it some more.

Controls are dependant on what your doing. High end stuff I do I use 9-12
wire, never less than 7 wire for the controls. Way to easy to have more than
enough than less. But then again I buy control wire on 1000 foot spools.

Hmmm. Same electrician said a 5 wire was plenty, as that's the maximum
number of wires he's seen.

Soldering WILL get ya in trouble maybe not right away but it will fail.
Silver solder is the only way to do it correctly. Also the ends need to be
welded shut.

Explain that welded shut bit, please.

I have a friend that used to be in the business, and used to be a
jeweler. He's the brazing master. Maybe I'll have to twist his arm to
come over and get his hands dirty for old times sake.

Thanks for the input.

R

Get a small rope or fish tape...insert rope or fishtape into the 3/4
copper with a knot on the end or bend small section of the fishtape out
about 90 degrees......bash the end of the 3/4 copper closed so that the
rope or fishtape wont pull out......tape or wire tie the 3/8 line and
thermostat wire to the end of the 3/4 copper...wrap the end of the 3/4
copper that will be pulled thru first with duct tape so that the end of
the insulation doesnt hang....pull lineset up cut off end that you have
ruined and seal with plastic cap or something....If I was gonna leave
it for any length of time I would braze caps on to both ends of both
lines and put a schrader type access fitting on one end.....then charge
with nitrogen and leave the nitrogen in there....just a few
psi...enough to let you know if a nail or anything has gone thru the
line after the wall or chase is closed back up.

~:

"RicodJour" wrote in message
ps.com...
Phil Scott wrote:
"Phil Scott" wrote in message
"RicodJour" wrote in message

I'm closing in a room that has a chase located next to
the
chimney. I
want to run lines for a future central air system while
the
wall is
open. There's a crawl space below, marginal access on
the
second floor
and good access in the attic where the air handler will
be
located.


If its not a stand up attic with stair step access (not
a
ladder) your repair guy will hate your guts... not to
worry
about him though, he will just all the grief to your
bill...with a smile.

Hey Phil. If I run the refrigerant and power/controls lines
so it's
all ready to go for him, that should make him smile, too.
The attic is
technically a stand up with a flight of twist stairs to get
you up to
the third floor/attic. Unfortunately the attic storage
space will all
go bye bye when the evaporator and ductwork are installed.

The stairs are good.



I picked up a 50' 3/4" & 3/8" line set which will work
with
the
anticipated 2 or 2.5 ton 2nd floor load.

yes that works

PS... one caveat.. best is to avoid soldering. the
2
ton unit will have a 5/8" suction line probably and a 1/4"
liquid line. so if there is a miss match you will have to
solder.

There has to be soldering at the ends in any event, right?

These days...yes... some are flared though.. the 5/8 suction
line set might well be flared... it depends on what the
condensing unit etc has...that would be your very best option.




The
nitrogen purge (sounds like a visit to the proctologist)
with the
meticulous soldering/brazing seems a little involved. Can
the
connections be done another way? Flare fitting perhaps?

some 3/4" unit connections come in flare most dont...in 5/8"
flare is more comon.



also if the evaporator coil is above the condensing unit
the
fat suction line you are showing will work just fine, an
advantage actually

Okay, sounds good. Why an advantage?

Less pressure drop in the suction line, results in higher
volumetric efficiency for the system. in your case probably
5% range.


if the air handler / coil is below the
condensing unit, the fat suction line can pose 'oil return'
problems if its much of a rise... if thats the case bend a
slight trap into the bottom of the riser on the larger
line.

It's not, so no problem.

a riser over 10' should be avoided.. especially if you end
up
with an oversize suction line as you are showing in the
event
of the 2 ton unit (size also dependent on the efficiency
of
the unit, check all that out...with the smaller unit, which
should be fine the 5/8" suction line is a lot easier to
bend,.
you can avoid all the soldering.

Have the 3/4", opened the box, rather not return it.


Return it...they are used to that....bring em a 6 pack if you
wish to be nice. the 3/4' is nasty to install compared to
the 5/8 a factor of5 to 1 more difficult.. the 5/8 bends
easily... the 3/4 is nasty.

If you had unplugged the ends and uncoiled it...then there is
a problem if its still coiled...no problem.




So it sounds like
for a smaller unit, 2 tons, the 5/8" is preferred, but the
3/4" is an
advantage (to be specified). Net plus or minus?

3/4 will give less pressure drop especially over the 50' run
you have... at two tons Id go with the 5/8 however...at 2.5 or
3 tons the 3/4 would be the hot set up.

Your load was calculated at peak design conditions though...so
you 2 tons is probably oversize for 95% of the time... you
could get by nicely probably with 1.5 tons... 5/8 suction
line would be the hot set up in that case.



bending trick,, try to arrange bends to match the way the
tube
is already coiled...bending it sideways or backwards is
more
difficult.. you can rent a lever arm tube bender for that
though.

I have a bender floating around somewhere. It's just a
question of
finding it at the right time. It looks like I'll need at
least three,
maybe four people to pull that line in one piece, assuming I
can cut
adequate holes in some tight locations.

I should make it clear that it's very doubtful that I'd be
doing the
system installation, so I'm not looking to make more work
for myself.
I'll hire a contractor in a few months or few years when the
project
goes ahead and let him worry about all of the connections
and such.
The driving force is my desire to not have to open up walls
down the
road. I hate cutting into my own work. Really.

So with that in mind, can I just cut the line set, pull two
sections
and leave access to the mating ends for the sub's connection
a few
months from now?

Not a bad idea... talent is getting scarce however, most dont
use dry nitrogen purge many dont know the basics... have them
use 'stay bright silver solder in a ROLL' melts at 400
F...good stuff... then pull a vacuum on the lines before
opening them to the system.



Is there a specialized cap of some sort to facilitate
pulling of the
line set?

No... you have to muscle that through...you idea of cutting it
in the middle and leaving access for a pro to solder is a good
idea especially if you stay with the 3/4" line set.




Is there something like a Fernco fitting with a loop in the
end to which the pulling line could be attached? I'm
concerned that
I'll rip the crap out of the insulation as I'm pulling the
line.

It would...thats why you dont 'pull' it..you sort of jam it in
while forcing the bends with yer hands... your idea of cutting
it and leaving access is good be sure to tape up the ends real
good with electrical tape (no need to solder them shut, that
will make the connection very difficult)


BTW, I could link you to some pictures of the project, 3D
CAD files, if
you're interested.



Phil Scott




thanks again

R

If there is absoluely no way to run the lines without having to make any
joints in them, then silver solder is a must. If you use anything else,
including flare fttings, you are just begging for trouble. Pressure test
the lines afterwards just to be safe, so just in case there is a leak at
a joint, it can be located and repaired while still accessable. Also, in
pulling the lines, be sure to carefully unroll the lines. DO NOT try to
pull them off from the edge of the roll, like stretching a coil spring.
You are guaranteed to kink them if you do. I have had more than one
helper do that, when I told them to feed me the lines as I pulled them
into the attic. I could have strangled them. Best bet-- do not try to
run them by yourself, and get a good dependable helper. You are not
real clear as to the electrical you are talking about running. Is this
for a gas furnace in the attic? If so, a 20 amp circuit with #12 should
be fine. Or are you talking about a line for the outside unit? If so, do
yourself a favor and run at least #10. Good luck Larry

Al Moran wrote:
On 8 Feb 2006 09:08:32 -0800, "RicodJour"
wrote:

I'm closing in a room that has a chase located next to the chimney. I
want to run lines for a future central air system while the wall is
open. There's a crawl space below, marginal access on the second floor
and good access in the attic where the air handler will be located. I
picked up a 50' 3/4" & 3/8" line set which will work with the
anticipated 2 or 2.5 ton 2nd floor load.

My questions:
- I don't see how I'll be able to run the line without having at least
one or two cuts/couplings. I've read silver brazing is better than
sweating the joints. How critical is the difference?

- Is flux a problem with making connections in a refrigerant line?
Alternatives?

- I'll be pulling a 12/3 line for the unit and to provide an additional
circuit in the attic. What wire should I pull for the AC controls?

- I've never pulled such a large line. With electrical I use a fish
tape. Can I use that to help pull the insulated copper? Any tricks to
keep the insulation from hanging up and getting ripped?


If you have to ask all of these questions then you should not be
****ing with it. Ther are so many things you need to know in order to
keep future problems at bay that one could probably not post them all
here. Good luck with all that.

I am not ****ing with it, I'll be running a line. The specifics are
the reason I posted - to gather information beforehand. Standard
procedure, no?

I've checked on a couple of manufacturers' web sites and the 3/4"
works, but the 3/8" may be a little large. I know a smaller size would
minimize the charge, but how much difference does that actually make?

So if the sizing is okay, and besides me putting a hole in the pipe,
the only future problem I see is the question of contamination. That's
where I am, and I'm open to suggestions and comments.

R

I would run a conduit or two for the electrical and cap them. Let them
run the wires through them when they install the A/C.