Open Forum

Direction of Home

  • 1.  Direction of Home

    Posted 20 days ago
    The Compass in my load calc program has eight points of direction. Residential projects. "A good amount of glazing"  I have  one project facing 210 degrees SW and one facing 53 degrees NE. These projects are just into SW and NE. I took the loads at South and North, then at SW and NE and averaged them out. With one unit it's the difference in a 3 Ton to 4 ton. Encapsulated homes and windows are at U. 28, SHGC.17-.14,
    The 4 Ton meets the load on low stage at 95 outdoor and 75 indoor. My problem is I think I'll be oversized when not at design temperature. I have a Dehumidifier included.

    First post,
    Much appreciated.

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    Ronald Newcomb

    Airmasters HVAC
    Mechanicsville VA
    804-539-2215
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  • 2.  RE: Direction of Home

    Posted 17 days ago
    So how far undersized is the 3 ton... whats the heat load? I take it this is a residence??

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    Pete Prydybasz

    PSP Consulting
    Mohnton PA
    610-775-3182
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  • 3.  RE: Direction of Home

    Posted 17 days ago
    The three ton will just meet the load at 95' Outdoor and 73' indoor. Heat load at 18 degrees is 43,000. 15,000 is infiltration. Home is semi tight but I usually set at average. Residence yes.

    Thanks a bunch.

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    Ronald Newcomb

    Airmasters HVAC
    Mechanicsville VA
    804-539-2215
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  • 4.  RE: Direction of Home

    Posted 17 days ago
    When u looked at the outputs of the units what loop temperature values did you use?
    Hopefully the worst conditions .. 
    I m leaning towards the 4

    Sent from my cell
    Please excuse any errors





  • 5.  RE: Direction of Home

    Posted 17 days ago
    I use EWT of 90 degrees.

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    Ronald Newcomb

    Airmasters HVAC
    Mechanicsville VA
    804-539-2215
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  • 6.  RE: Direction of Home

    Posted 17 days ago
    If that is the max your loop gets then you are good.... I suppose 30 wet heating.  
    From what you told me I would think the 3 ton would run a lot.. the 4 would cycle.. I am leaning towards the 4. If it's too much air you can dump some air maybe in the basement. The other thought is how much less cost would the install be with the 3 and how much back up would you need in the winter with the 3. How's the contractor requirement in the home?

    Sent from my cell
    Please excuse any errors





  • 7.  RE: Direction of Home

    Posted 17 days ago
    You can add back up heating but not cooling

    Sent from my cell
    Please excuse any errors





  • 8.  RE: Direction of Home

    Posted 17 days ago
    Much appreciated,
    I will go with the 4Ton. It is two zone with the basement. Basement will be wired on low stage only. Level one above, duct is sized for 1260 CFM,Carrier indoor unit on low CFM adjust. I'll use the modulating automatic round damper with static sensor off the plenum in case I get caught and need more heat in Basement I'll use the basement as a dump zone.
    Appreciate your help!!!!!

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    Ronald Newcomb

    Airmasters HVAC
    Mechanicsville VA
    804-539-2215
    ------------------------------