On Apr 15, 10:20 pm, firstname.lastname@example.org wrote:
Would you go outside the building or inside?
One thing I am having trouble invisioning is how the supply and return
air both are positioned on the unit? I mean when I drive down the road
and look at houses with a package unit, all I see is a "metal square"
going into a crawlspace. On metal businesses I see one square duct
going up the side of the building into the roof. Are both the supply
and return lines in that one duct?
I would look at my house but it has a split system.
I also found a guy selling split systems. He said the coolant is still
in the condensor like the factory. ALl that is required is brazing a
copper line from the condensor to the evaporator. It seems there are
alot of these air units around.
The package unti I qoted earlier sounds like it was a good deal. WOuld
2 tons be enough for a 30x30x10?
2 tons should do it if you insulate the place some.
Usually the return port is on the bottom and the supply is on top.
Take the return straight through the wall and duct the supply up the
wall, inside or outside. Just be sure you have an insulating chase
over the ducts if it is outside with the vapor barrier on the outside.
(where the warm moist air is)
Personally I would put the unit tight to the wall and run the ductwork
on the inside.
As for he guy who says the freon is still in the compressor on a
removed unit, what remains there is not as much as the "precharge"
from the factory. You will be adding some. I would not trust it
anyway. I would replace the dryers, draw it down and recharge any old
Legally they were supposed to recover all of that freon before they
broke the old machine apart.
The ducts are side by side on your typical package unit. If you go
under the crawl on a house that has one you'll see. Typically a
couple big pieces of flex run from there. If you are putting a
package unit against the side of your garage you could pretty much
butt a return vent right up against the unit. You would still need a
log piece of square duct to get to the attic from the outlet. That'll
be $100 or so from a sheet metal shop that specializes in duct work.
The refreigerant is inside the condensor but to install it properly
you braze or solder the lines, pull a vacuum on the lines and
evaporator. See if it holds to check for leaks. Then open the vavles
on the compressor to let the refrigerant inot the rest of the system.
A brand new system will have enough charge for an evaporator and x
feet of line. A used systemor longer line will require you to add
The trick to dealing with hvac supply houses is to do your research
ahead of time. You go in and know what you're asking for they will
usually not question you. As long as it's not systems. You need a
certificate and in most states a contractors license to buy a system.
But if all you're after is duct work or boots or somethingthey won't
hassle you. Also good to go middle of the day. Most ofthe pros hit
them first thing in the morning to get ready for a job. You want to
visit when they are not busy.
Thanks so much for the good advice! WOuld you guys run the duct up the
inside wall into the attic, then protrude the registers in the ceiling
or, like in come commerical buildings, would you just hang the duct
and registers below the finished ceiling?
A lot depends on the exact nature of your situation. I'd probably try
to go for a corner where I could box in the vent going up and run the
distribution above the finished ceiling. But I like to get
professional looking results and you might not care so much about that
in your garage.
I like professional results too, I just hate to have an odd blocked
corner. Going on the outside seems easiest but not sure.
I just went to my local Lowes and they have all kinds of duct
material. They dont have the "square duct" like I see on the outside
of building sometimes.
Does a plenium usually come with the air conditioner?
No the package unit will just have 2 rectangular flanged ports on the
You have to make or have made the plenum and the rectangular ducts.
Duct board is usually the easiest way to go and if you are out of
conditioned space the best way to go. Metal ducts will sweat like a
pig. The duct board comes in different thicknesses with different R
values. You use that "V" tool to define the corners and fold it up,
taping the final corner. Then you cut the holes for the round ducts
going out and the rectangular flange coming in.
It might actually even be worth going to a guy and having these built
if you can find someone who will do it. It might not be that much more
to just have it all installed.
When you get the whole thing done, build a chase around it with 2x4s,
insulate it and sheath it with whatever suits your fancy. The weather
will kill that duct board pretty quick.
It is a good idea to build a platform for the unit up off the ground
if flooding or snow are a problem.
In Florida it has to be above the FEMA flood plane.
On Apr 16, 2:30 pm, email@example.com wrote:
I planned on pouring a concrete pad myself for the unit. SO there is
no way to attach just regular duct to those two ports on the unit you
were describing? So the plenum has to be in conditioned space?
I learned alot reading this: http://www.alpinehomeair.com/related/Ductwork.pdf
All a plenium seems to be is a square of metal or duct board. I have
seen panels at Lowes that look like they snap togther. I am wondering
if I could make one? I could even mig weld it.
Could I make a metal one then line the insife with duct board to
insulate it? Go up to the attic with 14 inch metal pipe, a 90 degree
elbow then the insulated duct inside the attic? I think someone said I
would need to insulate this 14 inch metal duct somehow. Is there
insulation that is rated for outside exposure?
Again I appreciate it!
Metal is really more appropriate for heat. It will sweat when you have
A/C going through it. Just use the duct board and round flex duct.
That is insulated too. If you pull tight so it runs straight and
supported so it doesn't sag it performs as well as metal and a lot
easier to deal with.
I bet if you call around you can find an AC guy to do this for a
couple hundred bucks if you build the chase (after) and have the slab
Lowes only has the bare minimum. The bigger square stuff is usually
built to a specific application. Measure and do a rough sketch of
what you need. Find out who's building duct work around you.
Sometimes it sheet metal fabrication places. One of the local hvac
supply places near me also does sheet metal work. I'd stick with the
ceiling vents. Running it back down the walls just addds more
resistance to the whole system..
Man, I would look at a motel model PTAC like a GE Zoneline...
They don't cost all that much more than what you are looking
at spending on this used package unit which would require
ductwork to be installed (which will cost money to do right)
and a heavier duty electrical feeder which will have to be
installed in rain tight enclosures and with rain tight flexible
Is that used Bryant 2 ton unit from a commercial building ?
Does it need 3-phase power ? It is not something that will
be plug and play into a standard power outlet...
For just a about a hundred dollars more than you are looking
to spend on the huge outdoor unit and all the tools, ductwork
and electrical supplies you would need to install it, you could
buy a brand new 14,700 BTU PTAC unit which will cool, heat
using reverse cooling cycle and have a 5KW electric booster
heating element for when it is too cold outside to use the
reverse cooling cycle for heating; all fed from a unit which
only requires a 30amp 240v power outlet...
Simpler electrical install since it would all be inside wiring,
simpler unit install and it would serve you year round rather
than being summer only...
Just my thoughts man... Good luck...
On Thu, 15 Apr 2010 05:02:53 -0700 (PDT), firstname.lastname@example.org wrote:
They are designed for "sleeve mountable" or "through the wall"
conditioners - NOT window units - and the through the wall units are
not very common - and are relatively expensive.
Standard window units will NOT work in an apartment sleeve - at leat
not MOST of them.
It takes at leat 3 inches to get adequate airflow, and it has to be
properly baffled so the heat shed from the back of the unit is not
drawn back in the sides.
On Apr 15, 10:27 pm, email@example.com wrote:
The heat drawn back in the sides ?
On a motel PTAC: Packaged Terminal Air Conditioner there are no
"sides" exposed... On the exterior all that is exposed is the flat
with the louvers on it... The "sides" are inside the wall and the
of the unit is sticking out into the room on the interior...
*These are nice package units and are available with heat or without. You
would need to cut a hole for the ventilation grill to penetrate to the
The heat will collect in the high part of the roof. Unless you partition it
into rooms, and put a ceiling in there, you're pretty much cooling a lot of
hot air that won't feel any cooler. The sun load on the exterior of the
building will heat any cool air in the place immediately.
I've installed Bard package units and I like them because they're
high quality and have a lot of options. I installed one in a pizza
place that needed extra cooling in the kitchen during warmer months.
It's a metal building and the installation went quite well. I ordered
grills for it since we in stalled it through the wall without any
duct work. The discharge is a few inches from the ceiling and the
return is a few feet lower. It's a four ton 3 phase unit with several
factory options including a phase protection module to protect the
unit from any power problems, high and low pressure cutouts, low ambient
temperature control and the 2" thick pleated filter option. It's given
zero trouble in four years. the only maintenance has been changing
filters and cleaning the condenser once a year. Pizza places are very
rough on air conditioners.
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