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  1. #53
    I have one last question, Obviously the 16 seer units from Trane and Amana are both 2-stage compressors but I have downloaded HVAC-Calc and completed a load analysis and the recomendation is 2.5 tons. (Below are the actual gains/losses) My question is going with a 3-Ton 2 stage compressor going to be overkill? I beleive in both applications the matching proposed coil is about 40,000 BTUH. The proposal for a 14 seer sytem from either brand was for 2.5 ton Heat Pump and 31,000 BTUH Coil. Both application will use a Variable Speed blower.

    Sensible Gain 23,586
    Latent Gain 4,247
    Total Heat Gain 27,833
    Total Heat Loss 64,284

    [Edited by ifucdseeme on 10-25-2005 at 10:56 PM]

  2. #54
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    There is a XL16i equipment matchup that will very closely match your sensable cooling requirement if the blower is set at 350 CFM per ton. Even at 400 CFM per ton it wouldn't be considdered oversized.



    Amana has a matchup with almost exactly the same ratings.

    [Edited by mark beiser on 10-25-2005 at 11:27 PM]
    If more government is the answer, then it's a really stupid question.

  3. #55
    Originally posted by mark beiser
    There is a XL16i equipment matchup that will very closely match your sensable cooling requirement if the blower is set at 350 CFM per ton. Even at 400 CFM per ton it wouldn't be considdered oversized.

    Amana has a matchup with almost exactly the same ratings.

    [Edited by mark beiser on 10-25-2005 at 11:27 PM]
    I think you might be onto something Mark! I am not sure why the both quoted the larger 3.0 ton coils with their proposal. I will try and give both a call tommorrow to discuss the smaller 37,000 BTUH coil. I also think setting the blower to 350 CFM makes alot of sense here in PA, as it can get very humid in the summer and that should work a little better for pulling some moisture out of the air. Thank you!

    BTW - Why are all Heat Pumps rated at nominal cooling capacity instead of Heating which by my load calcs seems to be over double the BTUH of the cooling requirements of the system.

  4. #56
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,964
    Indoor coil never determines capacity of the system, only the compressor and configuration of the outdoor coil as related to the indoor coil determines capacity.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  5. #57
    I have read so many post disguraging oversizing. I just want to make sure I get the proper equiptment to be comfortable year round. So assuming a 3ton 2 stage outdoor compressor, variable speed blower and my above Load Calculations. Which indoor coil will be best matched the 37,000 BTUH or 40,000 BTUH, and why?

    I am really getting into this, I have learned so much, this is really a great place, Thanks to everyone who has contributed!

  6. #58
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Originally posted by ifucdseeme BTW - Why are all Heat Pumps rated at nominal cooling capacity instead of Heating which by my load calcs seems to be over double the BTUH of the cooling requirements of the system. [/B]
    Because enough electric auxiliary heat gets installed to make up the difference in heating capacity.
    If you sized the heat pump for the heat loss of the house, it would be grossly oversized in the cooling mode, wich is a whole other can of worms.

    Always size a heat pump to the cooling load.

    Ideally the auxiliary electric heat should be sized to the total heat loss. Then an outdoor thermostat installed to keep one or more of the heating elements off, unless it gets below the setpoint of the outdoor thermostat.

    The outdoor temperature where the heat loss of the house is higher than the heating capacity of the heat pump is called the ballance point. In the case of a 2 stage heat pump there are 2 ballance points.

    When the outdoor temperature is above the first ballance point, the system will cycle on and off on 1st stage heat.

    When the outdoor temperature is between the ballance points, the system will run in 1st stage heat constantly, and cycle 2nd stage heat on as needed to maintain the setpoint.

    When the outdoor temperature is below the 2nd ballance point, the system will run constantly in 2nd stage and cycle the auxiliary heat as needed to maintain the set point.

    By the time it is cold enough for the auxiliary heat to be cycled, the indoor temperature may be as much as 2º below the desired setpoint. A lot of people will bump the set temperature up a degree or two to maintain thier comfort level, I know I do.

    If your installing contractor is controls savy, and you don't mind a little higher energy usage to maintain comfort, the system can be set up with an outdoor thermostat and a relay to run one of the heating elements when there is a 1st stage call for heat when it is below the temperature the outdoor thermostat is set for.
    I have done that a few times for people who couldn't stand the mild heat from the heat pump running constanly. I wire the NC contacts of a relay in series with the outdoor thermostat and energize it with O from the indoor thermostat. This prevents a heating element from coming on with a call for cooling if the outdoor thermostat fails closed or the system is run in the cooling mode when the outdoor temperature is lower than the set point of the outdoor thermostat.

    [Edited by mark beiser on 10-26-2005 at 12:24 AM]
    If more government is the answer, then it's a really stupid question.

  7. #59
    Join Date
    Oct 2005
    Posts
    1

    Salt water?

    Howdy everyone,
    This forum has been very helpful, we need a new unit and were looking at the Amana 3.5 ton 14 Seer but we do live on salt water, why is the Trane better?

  8. #60
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Where?There's a difference only if you are close by and there's a lot of surf,so salt spray is a factor.

  9. #61
    Join Date
    Sep 2005
    Location
    Central PA
    Posts
    9
    ifucdseeme...

    I completely forgot to get pics of my install. Let me knwo if you still want them, and I will grab some tomorrow after work.


  10. #62
    Originally posted by novadude
    ifucdseeme...

    I completely forgot to get pics of my install. Let me knwo if you still want them, and I will grab some tomorrow after work.

    If I choose the Trane system, which is where I am currently leaning, I will not be using the same contractor as you did. Not because I am worried about the quality of the install but there prices on the exact equiptment was sugnifficantly higher then the other two Trane quotes I got. I would still like to see some picture of your indoor and outdoor install. Thanks you.

  11. #63
    Join Date
    Sep 2005
    Location
    Central PA
    Posts
    9
    Check your e-mail... I sent pics of the outdoor unit. I'll get some indoor pics this weekend.

  12. #64
    Join Date
    Jun 2003
    Location
    Hell Hole Swamp
    Posts
    4,180

    Re: Salt water?

    Originally posted by cmdgk
    Howdy everyone,
    This forum has been very helpful, we need a new unit and were looking at the Amana 3.5 ton 14 Seer but we do live on salt water, why is the Trane better?
    All aluminum coil instead of copper/aluminum, therefore greatly reduced galvanic corrosion which is accelerated by the salt, In my experience Amana does poorly in a salt air environment

    [/threadhijack]

  13. #65
    Originally posted by novadude
    Check your e-mail... I sent pics of the outdoor unit. I'll get some indoor pics this weekend.
    I got you email and pics, Thank you. Sent you an email back

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