Modulating compressor (Nordyne - iQ Drive)

[dp563]

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

[tinknocker service tech]

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

[mchild]

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.

[dp563]

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

[k-fridge]

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.

[aircooled53]

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.

[mark beiser]

68º inside the house in the summer? Yer crazy!

Seriously though, that will be harsh on any residential HVAC equipment.

[Shophound]

68º 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.

[dp563]

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

[tpa-fl]

68º 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.

[mark beiser]

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.

[Shophound]

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.

[CottyGee]

68ºF is a friggin' ICE BOX! I get cold in our house with our new system running at 74º after a coupla hours not moving, like watching a movie.