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What heat/AC package unit?

Zeke

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Long Beach CA, the sewer by the sea.
Did a search here and on the Giggle. I have aprox 1300 feet of single story, old 1930 stucco with no insulation in the walls. I'm figuring more or less 3 ton combination roof mounted package unit with probably a downflow return and supply. I'd like to buy direct and set this unit myself on a curb on my flat roof.

Goodman or what should I be looking at? Places to buy this? So far I've been poking around on ACWholesalers site but that's the only one I've visited.

One more note: I'm planning the distribution system and using an online calculator. Due to the layout of the house, I will have only 8 registers. I'd provide more info but I don't have all of it yet. If there is any specific info any of you pros would like I'll get it.

The climate is coastal Mediterranean. Lowest lows are 40º and the late summer (6 weeks) is consistently 90º with a +- 5 degree factor.
 
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Zeke

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Trane and Carrier seem to head the list. Talked to an HVAC consultant today and I'm less inclined to buy direct to public now. I think I will go about designing my distribution based on my load calcs and have it checked by an HVAC guy with the software he has. Hopefully said HVAC guy will cotton to buying me a pack at the local wholesaler and spotting in on my roof curb.
 
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LS6 Tommy

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8 drops is kind of a low count for 3 tons. Your gonna have air noise & high static pressure (& thus a low delta T) unless they're BIG...

Tommy
 

pseudorealityx

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8 drops is kind of a low count for 3 tons. Your gonna have air noise & high static pressure (& thus a low delta T) unless they're BIG...

Tommy

It's 150 cfm per diffuser. That's well within 'normal', but it depends on the layout obviously.
 
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Zeke

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OK, I looked in and saw some posts. 8 is a small amount. I don't have a plan view as of yet to scan, but that's in the works. Imagine if you will the east side of the house being the short wall of the living room which is wide open through an arch to the short side of the dining room at the center and the short side of the kitchen on the southeast corner.

Rounding that corner and going west is the length of the kitchen and bed no 2. There is a closet in between. Of course these are the 2 hottest rooms in the summer. Across the back or west side is the short side of the bedroom a bath in the center and mas bed on the north west corner. Another closest along the north wall and you're to the long side of the living room. There is an added bath on the west wall serving the mas bed.

OK, volumes are just a WAG at this point but each bed is close to 960 cu ft, the kitchen is similar, the living room with a vaulted ceiling is likely 1500 cu ft and add in a small breakfast room and 2 average baths. The dining area where the conditioned air will move through a 10' arched opening and to the hall is another 1000 cu ft. The supply to the living room will have to be enough to compensate. This is the area that the thermostat will be intstalled as it's the most protected and ambient room. The rest is internal closets and hall where the return air would be quite centrally located as every room opens in some way to the hall. Ideal layout AFA return air is concerned.

I know unless you've been sketching while reading that this is all vague. I would put 2 large registers in the living room and let that conditioned air flow back through the dining room into the return area. Therefore, no register in the dining room. The window is very sheltered. Not so much for the living room which can get some morning sun in the summer. An awning would help there.

2 down and 6 to go. The kitchen needs a register and I'd use 2 but I'll put one in the breakfast cubby and let it flow back through the kitchen to the hall. The main register for the kitchen would be over the door on the south wall and far enough away from the gas range so as not to disturb the air going up the hood when in use (not often).

One register for each bed in an area so as to not disturb the sleeping portion. Likely the typical 12 x 6. 2 left and those would be smaller ones in each bath. I know the trick is to calculate the load for each area, size the duct work and distribution model and size the boots. Likely it will be a hybrid radial arm system going to a wye branch of no more than 4 registers for each branch off the plenum. Sort of a left/right affair.

The whole joint sits on a 30 x 40 rectangular footprint with one addition bump out, and a front porch recess covering the dining room window. The unit will sit centrally over the hall. Not enough room in the attic crawl space to locate the unit, so it goes prox 30" above the ceilings on the flat roof.

This may not be ideal but part of the consideration is aesthetics and comfort AFA conditioned air disturbing the seating and sleeping positions. I may go overboard with the consultant and pay what will be near a thousand bucks for a complete plan. Here's what he proposes:

The design would be for a single gas/electric package unit roof mounted.
The house is approximately 1300 Sq. Ft., single story.
Owner to supply sketch with dimensions and photos.
Duct system would likely be a combination of radial arm and ‘Y’ branch using flex duct.
Single filter grille.
Programmable thermostat.
Project to include HVAC load calculations, computer duct design, and equipment recommendations.
Design to include AutoCAD drawings of HVAC layout, equipment schedules, and detail drawings.
******** Consulting to assist in acquiring HVAC equipment direct to owner.
Discussed project fees estimated at $980.00.


I underlined equipment recommendations because I told him if he did this he would also need to provide me with a complete materials list for everything. That will be a big time saver for me as I don't know all the nomenclature for every part. I have installed 3 forced air systems before, but I'm a stone novice at this. So other than a few tie wraps and sheet metal screws, I expect to have everything I need dropped in the drive ready for the crane.
 

pseudorealityx

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I'd add one to the dining room.

I understand your logic, but the idea is that you provide enough air to the living room to maintain it's temperature. However, that process with heat/cool that air towards ambient, where it won't have any additional heating/cooling capacity left over for the dining room.

Remember you'll need exhaust fans for the bathrooms as well.

Make sure a solid curb is built for the unit to avoid noise/vibration issues.
 
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Zeke

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Long Beach CA, the sewer by the sea.
I'd add one to the dining room.

I understand your logic, but the idea is that you provide enough air to the living room to maintain it's temperature. However, that process with heat/cool that air towards ambient, where it won't have any additional heating/cooling capacity left over for the dining room.

Remember you'll need exhaust fans for the bathrooms as well.

Make sure a solid curb is built for the unit to avoid noise/vibration issues.

Thanks. I'm sure any software I of anyone else will use will agree with you. I'll look for a place that isn't going to mess up what is a highly decorative ceiling. Maybe I can cut a plate and sneak a 3 x 13 rectangular duct down a little past the coved ceiling and put that one on the wall. Fortunately there is a kitchen cabinet on the other side. I could even place that flat duct inside the cabinet and through the wall w/o hassling cutting the plate. This additional register will wash the front window with air. That area would have been sort of a dead area anyway with the air biased towards the hall.

That's why I write so much, along with your suggestions it helps me see the situation more clearly. I'll work on a plan view. I think I can do this faster on paper than in Sketchup, but I'll look into SU. I haven't used it sin 4 years.

Figure 9 boots now.
 

KoRNTERA

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Feb 23, 2014
Messages
11
It's 150 cfm per diffuser. That's well within 'normal', but it depends on the layout obviously.

Up to 150CFM, bad ductwork with bad diffusers will put you typically closer to 100 CFM. An average diffuser cuts back surface area by 30% and the best designs still take up 20%

OP, I would highly recommend against buying on
One, you do not usually get a local warranty and while goodman is making strides in their quality they are not up to par with Trane, Carrier,American Standard and Rheem or Ruud.
Over sizing is also bad so you will want somebody to design the right size system for you and a 2.5 ton may be the answer.

My new house is a 3,500 sq foot home,3 stories with a 2.5 ton heat and cooling load so even though your home is older, you might be better off upgrading a few things instead of putting in a larger heating unit.
 
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