"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