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2 stage residential systems and humidity

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  • Gordy
    Gordy Member Posts: 9,546
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    Don't worry the wifey will be the true test Chris :D
  • ChrisJ
    ChrisJ Member Posts: 15,913
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    Gordy said:

    Don't worry the wifey will be the true test Chris :D

    You don't know me or the wife.
    I'm far more picky.


    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,829
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    Cause oversized and dehumidification are are opposed to each other
  • Gordy
    Gordy Member Posts: 9,546
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    what happens on below design day........
  • njtommy
    njtommy Member Posts: 1,105
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    It runs at 20,000 btus of cooling on first stage so he should be ok. Below design days.
  • Gordy
    Gordy Member Posts: 9,546
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    I thought two stage was still up in the air? Chris?
  • ChrisJ
    ChrisJ Member Posts: 15,913
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    njtommy said:

    It runs at 20,000 btus of cooling on first stage so he should be ok. Below design days.

    Gordy said:

    I thought two stage was still up in the air? Chris?


    2 stage is still up in the air, just not sure yet. I'll figure it out when the time comes.

    36,000 unit runs at around 27,000 in low stage.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • ChrisJ
    ChrisJ Member Posts: 15,913
    edited January 2017
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    Right now I'm trying to get my YellowJacket Brute II's to stop leaking, and I'm not impressed at all.

    Factory installed NPT connectors for the hoses were not even close to tight and were leaking. I cranked them in to what I felt was correct and am now testing.

    Confidence is high, repeat, confidence is high.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • ChrisJ
    ChrisJ Member Posts: 15,913
    edited January 2017
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    Cause oversized and dehumidification are are opposed to each other

    Ed, it's not oversized if he wants a 20F drop on the design day.

    And, that is exactly what he wants.

    Ed,



    It's "oversized" to those who find an indoor temp of 80F acceptable.
    I do not, 75F is about as warm as I want to see. We generally want to run 70-72F depending on the outside temp. Previously have used 2.5 tons worth of window units and they fell short of what I feel is appropriate. Just before I pulled them out I did some testing on them to make sure they were performing properly, and they were.


    When doing the manual J we messed around with the settings some, such as 75F @ 95F, and 70F @ 90F and it was still close to 3 tons. If I recall, 75 @ 90F got me down to about 2.5 ton. This also did not take duct loss into the attic into consideration and even though I'm using R8 for everything I'm sure there's going to be a noticeable loss when the attic is 120F. Duct work will be primarily 14" hard pipe with short runs (2-3 feet) of R8 flex and 10" hard pipe drops to the first floor, likely insulated with R4 or R6 just for condensation concerns but most of it will be in the attic, which stinks, but it is what it is.

    Fact is, no one makes a 2.5 ton 2 stage unit anyway so it's actually a moot point so I'm still back to 3 ton if I go 2 stage.


    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • BobC
    BobC Member Posts: 5,480
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    Say what you will about window shakers but they can do a great job. My first floor is 625 sq ft, the house is 100 years old and had little insulation in the walls. A single 13,400 BTU Panasonic window unit could keep that whole first floor at 70 when it was 95 out and had no difficulty doing it. It was cool and bone dry.

    Las summer I had the walls insulated and installed a 12,000 BTU Mitsubishi mini split. It works ok but the old Panasonic did a much better job, it cooled faster and it dehumidified better despite the uninsulated walls at that time.

    I've found it does a better job of heating than it does of cooling, I can keep the first floor at 68 down to about 30F outside.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • GW
    GW Member Posts: 4,736
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    Chris, you did a manual J but you did not account for the ducks in the Attic? Can you redo the manual J? That is all a part of the whole process
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • ChrisJ
    ChrisJ Member Posts: 15,913
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    GW said:

    Chris, you did a manual J but you did not account for the ducks in the Attic? Can you redo the manual J? That is all a part of the whole process

    I wasn't planning on any ducks.
    Do I have to have ducks in the attic? :)


    A friend from the forum did it with me, I don't think his program allowed compensation for that, but I can surely ask. He helped out a lot and I don't want to outstay my welcome.

    @BobC
    I had a 12,000 btu/h window shaker doing 800sqft on the first floor.

    It did ok except for during very hot days.

    Second floor had 19,000 which did ok most of the time as well, except we weren't cooling a big center area.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • JUGHNE
    JUGHNE Member Posts: 11,102
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    PTAC's, which are expensive wall shakers, seem to be the single largest heat loss if not running. Go to any hotel when they are off and it is like a metal ice cube stuck on the wall. Turn them on and there seems to be no heat loss.
    I realize these are in the heating mode......but the point is that any wall penetration is both a conductive and air infiltration heat gain/loss factor. Any window AC has to devote part of its cooling to overcome the losses incurred by the fact of it's installation thru the wall/window.

    Also, there is the psychological effect of the noise that lets you know it is cooling your body off. Most of the ones I have been around seems that when they cycle off, you start to feel hot again.
    So adding up the total cooling Btus of window AC's may not be a good indicator of what you need for central AC. FWIW

    BTY, ducks in your attic only add to the R-value of insulation by virtue of their feathers. ;)
  • BobC
    BobC Member Posts: 5,480
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    Down is great insulation, not sure about the duck poop.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • GW
    GW Member Posts: 4,736
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    My apologies, I was voicing the text and didn't proof my efforts.

    Yes the manual J process must account for where the ducts are, what level of duct sealing is present and how much insulation in on the ducts
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • ChrisJ
    ChrisJ Member Posts: 15,913
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    GW said:

    My apologies, I was voicing the text and didn't proof my efforts.



    Yes the manual J process must account for where the ducts are, what level of duct sealing is present and how much insulation in on the ducts

    I asked, his program doesn't offer that, nor did the manual J sheet I got from someone here, may have been @JUGHNE.

    The ducts will be sealed most likely primarily with clear RTV, I doubt there will be much leakage if I can help it.

    Truth is, if anything, adding the attic losses is going to make the system even bigger and I'm not going to a 3.5 ton.


    Perhaps we can trade the window shaker losses for the attic duct losses @JUGHNE ? :)

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • njtommy
    njtommy Member Posts: 1,105
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    Just go duckless and be done already. Lol.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,829
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    I agree with @JUGHNE about the window units. They have their place, I am not putting them down but central air (properly done ) has better air distribution. I have yet to see a job where central air couldn't do the job with less tonnage.

    Me, I find I am perfectly happy @74-76 if the humidity is being controlled.

    The lower the evap. temp the more your efficiency drops due to the increased compression ratio which will happen with 70 deg room air.

    Also your still going to be able to make 70 deg with the 2 1/2ton just not on a design day. On a design day the unit will be running constantly (2 1/2ton) and will be dehumidifying better because it is running. Unless you stare at the thermometer you will never know that the sensible temp is creeping up a few degrees.

    How many design days are there anyhow?? And when the sun goes down the unit can catch up, same thing in the morning just because it's 90 out the heat hasent been absorbed into the house yet.

    Guess if your staying with 3 tons I would go 2 stage
  • njtommy
    njtommy Member Posts: 1,105
    edited January 2017
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    Here's some of the info from my area of Nj this past summer. It was pretty consistent. Chris's is probably pretty similar.
  • njtommy
    njtommy Member Posts: 1,105
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    Here's my data logs from this past summer.
    1800 sqft rancher
    3 ton single stage unit.
    ChrisJ
  • ChrisJ
    ChrisJ Member Posts: 15,913
    edited January 2017
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    So after tightening the hose connectors into the aluminum manifold and dunking in water again and then pressure testing two, or 3 more times, I can't remember, I'm confident in my Brute II set from 2008.

    It seems there's always a slight drop in the beginning, but they held pressure for 90 minutes with no drop after the initial slight drop. I assume the hoses stretch, or something. This is done using dry nitrogen of course.

    I'm not used to dealing with this, the highest I've ever gone pressure testing a Monitor Top was 20 or 30 PSI and that's pushing the limits.





    So, onto the next step.


    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • ChrisJ
    ChrisJ Member Posts: 15,913
    edited January 2017
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    So,

    The project I started back in August of 2016 is finally starting up. Just ordered the rest of the parts and insulation for the ductwork.

    It's amazing how expensive duct work becomes as things add up, without labor.








    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Gordy
    Gordy Member Posts: 9,546
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    Believe me the insulation for the attic ductwork will not be a waste. Have you decided on two stage?
  • ChrisJ
    ChrisJ Member Posts: 15,913
    edited January 2017
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    Gordy said:

    Believe me the insulation for the attic ductwork will not be a waste. Have you decided on two stage?

    Not yet, no.
    Luckily, it doesn't really effect anything so I can put that off until the end.

    What I will say, is I'm still not impressed by the tiny effect the 2 stage systems have (36,000 only dropping to 28,000), and the worse SHR.

    Chances are, I'll end up with a cheap single stage outdoor unit, and a decent variable speed air handler. I really like the idea of running the blower really slow.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Gordy
    Gordy Member Posts: 9,546
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    I think you will want near constant circulation to eliminate hot blasts of warm soaked ductwork between calls.
  • ChrisJ
    ChrisJ Member Posts: 15,913
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    Gordy said:

    I think you will want near constant circulation to eliminate hot blasts of warm soaked ductwork between calls.

    Negative.
    Constant blower dries off the evaporator, into your living space.

    Bad idea.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Gordy
    Gordy Member Posts: 9,546
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    You'll see.
  • ChrisJ
    ChrisJ Member Posts: 15,913
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    I've dealt with it at work for 10 years there's nothing to see ;)
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Tinman
    Tinman Member Posts: 2,808
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    I think what you're looking for is a Liebert unit that's used for server rooms.
    Steve Minnich
    njtommyGordy
  • Tinman
    Tinman Member Posts: 2,808
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    When my wife and I bought this house, it had a 2.5 ton system in it. We buttoned up the envelope and and now cool it with 10,000 BTU/h. If it were up to me, we'd keep it cool enough to hang meat from the ceiling. But there's no need for that if you size the equipment properly and control the humidity.
    Steve Minnich
    GordyChrisJ