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  1. #1
    Join Date
    Sep 2004
    Posts
    26

    Modulating compressor (Nordyne - iQ Drive)

    Hi all,

    I'm in the Philadelphia area, having the HVAC upgraded in my existing home. Large house, 4 systems. Trying to decide on a contractor and evaluate their different brands. I like it very cool in the summer. Like it 68 degrees inside no matter how hot it is outside. So I need a lot of capacity. But, don't want systems to short-cycle and not remove enough humidity when it's mild out. Figured 2-stage A/Cs with VS blowers was the way to go. But then I see that Nordyne (Westinghouse, Frigidaire, Maytag, etc.) offers this new 23 SEER system with a modulating compressor ("iQ Drive System") - reminiscent of the old Trane XV15 from the late '80s. (Yes, I have done my homework.) In theory, I should be able to oversize the hell out of the systems so that even mid-afternoon if it's 100 degrees and sunny out, the house can maintain 68, but it should modulate down so that in the evening if it's 70 degrees outside and muggy, it runs steadily and doesn't short-cycle, and removes enough humidity. Am I correct in this assumption? Anyone have any experience with these units? I've been considering Rheem/Ruud 2-stage, ICP (Comfortmaker/Arcoaire/Heil/Tempstar) 2-stage, etc. but this Nordyne stuff seems like far superior technology. Anything I need to watch out for?

    Dave

  2. #2
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    those trane units were IMO way ahead of thier time. Alot of techs didnt like them but they were great units if installed right and set up properly

    to bad trane did away with them because in todays market they would outsell any other brand hands down

    remember the bigest draw back is the time it can take to diagnos one. With out the book you are lost in space no matter how good a tech you are

    this will hold true with what you have in mind. If you go this route then make dam sure you get all the booklets and paper work because with out it you will find techs walking away or recomending replacing them just like happened to trane

  3. #3
    Join Date
    Sep 2006
    Posts
    1,253
    Do a search on this site for Nordyne, Maytag, 23 SEER and such and you will see that there have been several discussions about these units. I think you are heading in the right direction. Personally, I'm waiting for the heat pump version as I will be able to size closer to my heat load and and still not be over cooled.

  4. #4
    Join Date
    Sep 2004
    Posts
    26
    Thank you, I did search through and find the other threads on this topic and read them thoroughly.

    One question that comes to mind now is, does anyone know where I can find a spec sheet of the different sizes offered, and what the dimensions of the condensing units are - I need to know the physical size of each different capacity offered to see if these units will fit beneath a window.

    Thanks again everyone,

    Dave

  5. #5
    Join Date
    Jan 2006
    Location
    Near Atlanta, GA.
    Posts
    14,562
    Quote Originally Posted by dp563 View Post
    Thank you, I did search through and find the other threads on this topic and read them thoroughly.

    One question that comes to mind now is, does anyone know where I can find a spec sheet of the different sizes offered, and what the dimensions of the condensing units are - I need to know the physical size of each different capacity offered to see if these units will fit beneath a window.

    Thanks again everyone,

    Dave
    www.nordyne.com

    The IQ Drive is offered in the Westinghouse, Tappen, and Frigidare line I think.

  6. #6
    Join Date
    Jan 2002
    Location
    Ft.Worth,Tx
    Posts
    4,584
    Quote Originally Posted by dp563 View Post
    Thank you, I did search through and find the other threads on this topic and read them thoroughly.

    One question that comes to mind now is, does anyone know where I can find a spec sheet of the different sizes offered, and what the dimensions of the condensing units are - I need to know the physical size of each different capacity offered to see if these units will fit beneath a window.

    Thanks again everyone,

    Dave
    35 1/2x31x40
    w d h
    2,3,4 ton split systems and they are coming out with heat pump soon.
    With 12 years parts and labor warranty and durability replacement if compressor fails new unit will be installed.
    Also if you install 90% furnace you will get 1200.00 rebate from Maytag.
    "Everyday above ground, is a good day".
    "But everyday that you have made a difference in someones life, may insure you stay above ground a little longer".<aircooled>

  7. #7
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    68Ί inside the house in the summer? Yer crazy!

    Seriously though, that will be harsh on any residential HVAC equipment.
    If more government is the answer, then it's a really stupid question.

  8. #8
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    Quote Originally Posted by mark beiser View Post
    68Ί inside the house in the summer? Yer crazy!

    Seriously though, that will be harsh on any residential HVAC equipment.
    I can get an approximately 800 square foot room down to 60 degrees with chilled water. This has come up more than once...somebody wanting to keep their house unusually cold...and the first thought that pops into my mind is, "Get a chiller". I'm not talking about some 100 ton centrifugal; there are air cooled chillers made specifically for the residential market.

    For a sixty-eight degree house temp, get an air cooled chiller and treat the chilled water loop with glycol (the less toxic variety) for outdoor freeze protection and to protect the heat exchanger. At the air handler put a three way valve on the chilled water coil and then modulate it by space temperature deviance from setpoint. Put a true variable speed blower on it (works off an inverter or VFD responding to a control signal vs. dip switch logic) and blower speed is controlled by cooling demand, shifting the load toward sensible during the heat of the day and toward latent in evening and morning times, and during shoulder seasons.

    I would bet, with a set-up like this, that the homeowner would find quickly that he could keep the temperature a bit higher, because a coil set up this way will dehumidify very well.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  9. #9
    Join Date
    Sep 2004
    Posts
    26
    Which manufacturer(s) make smaller-sized, residential, air-cooled chillers, and which manufacturer(s) make appropriate VS air-handlers? And how would I find a competent contractor? Look for a commercial refrigeration contractor? Cost isn't really a concern; quality and comfort is... I don't ever plan on moving from this house, ever...

    Dave

  10. #10
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    Quote Originally Posted by mark beiser View Post
    68Ί inside the house in the summer? Yer crazy!

    Seriously though, that will be harsh on any residential HVAC equipment.
    Why would that be tough on a resi HVAC system? I'm using a 4 ton TWE AH + 3 ton XL12 condensing unit at a commercial building to cool off a ~10'x12' room to ~55F. Been running 24/7 for the past 5 or so years without a problem. Replaced the TXV, added a freezestat, (de)humidistat, and have the airflow set substantially higher than normal due to the lack of latent load in room, but it's been running fine, even during 2 hurricanes.

    Yes, I'll admit that this is the REVERSE of the way I normally do AC in Florida, but when you've got a room with an equipment load that draws ~20,000 watts at full-throttle, latent heat isn't an issue.

  11. #11
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by tpa-fl View Post
    Why would that be tough on a resi HVAC system? I'm using a 4 ton TWE AH + 3 ton XL12 condensing unit at a commercial building to cool off a ~10'x12' room to ~55F. Been running 24/7 for the past 5 or so years without a problem. Replaced the TXV, added a freezestat, (de)humidistat, and have the airflow set substantially higher than normal due to the lack of latent load in room, but it's been running fine, even during 2 hurricanes.
    Yeap, with modifications, you can do lots of things that normally would kill the equipment.
    If more government is the answer, then it's a really stupid question.

  12. #12
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    Quote Originally Posted by tpa-fl View Post
    Why would that be tough on a resi HVAC system? I'm using a 4 ton TWE AH + 3 ton XL12 condensing unit at a commercial building to cool off a ~10'x12' room to ~55F. Been running 24/7 for the past 5 or so years without a problem. Replaced the TXV, added a freezestat, (de)humidistat, and have the airflow set substantially higher than normal due to the lack of latent load in room, but it's been running fine, even during 2 hurricanes.

    Yes, I'll admit that this is the REVERSE of the way I normally do AC in Florida, but when you've got a room with an equipment load that draws ~20,000 watts at full-throttle, latent heat isn't an issue.
    All that is true, but Mark's comment was likely based on an average residential installation being asked to do an unusual task...hold a space temperature, with no modifications to structure or equipment, considerably below average. Residences will always have a considerable latent load, particulary in humid climates, but even in dry climates if the house is tight it will have an interior latent load. Pushing lots of air through the coil to keep it above freezing would kill latent capacity, and the average homeowner would find the noise levels unacceptable.

    Overall, I think those who think they must run a house that cold (68 or lower) have not really quantified what range of parameters they would be comfortable at. They have a temperature number fixed in their head and that's the end of it. Realistically, if they lived in a humid climate, they might find they could be comfortable at a higher temperature if not only their system had good latent capacity, but that the house itself had infiltration under control and was insulated well. Get infiltration and the mean radiant temperature of the structure's interior surfaces under control, and it won't have to be so friggin' cool to be comfy.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  13. #13
    Join Date
    Mar 2007
    Location
    Phoenix, AZ
    Posts
    574
    68&#186;F is a friggin' ICE BOX! I get cold in our house with our new system running at 74&#186; after a coupla hours not moving, like watching a movie.

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