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  1. #1

    New Maytag IQ Drive System

    Hello all,

    Firstly I wanted to let you all know what a great Forum this is. To be able to follow indepth discussions regarding HVAC topics from half way around the world is absolutely wonderful! I am currently in Afghanistan and am a 1st time homeowner. I have the Misses back home handeling everything but it is this Forum which allows me to do my DD while not physically being home. THANK YOU ALL FOR THIS!

    On to my questions.... First a little backround - My current unit is a 1988 Carrier 5 Ton unit that consumes 9.1 KW as soon as it comes on. I plan on installing solar by this next summer and a 9.1 KWH draw is unacceptable. My home is in Lake Elsinore CA. The avrege ambient outside air temps in the summer is 110 - 118* respectively.

    I have been reading a lot about the I.Q. Drive system and have recently received a quote for the system. All the documentation I have received and can find from Nordyne is on the PS4Bi systems which only go as far a 4 ton. My rep said that this year they have made a 23 SEER AC unit which is a 5 ton but I cannot get any information on it.

    I also will be getting a Maytag PGC2MQ - 120 - D - VD iQ Drive 97% AFUE M1200 Furnace. I have attached a PDF that gives further details of the 2, 3 and 4 ton additional specifications my rep received from Nordyne and has passed on to me which I hope some of you will find informational with regards to current darw.

    On page 8 of the attached document you will see how the KW draw at different tempatures with wet and dry bulb conditions. What I am inturpeting is that from what I can tell is the system is sort of cheating when it is factoring it's SEER rating. By that I mean that if you look at the very bottom chart "4 Ton iQ Air Conditioner, with G7 Gas Furnace, D’ Cabinet" and look at current draw for outside ambient air temps of 110* to 120* (which is our hottest temps n our area in the summer) of the 4 speeds available the system will only run in "intermediate and minimum mode" and aove 120* the system will only run in intermediate mode darwing only 2.43 to 2.48 KW respectively. Given that they do not give the CFM of the fan in the heater cabinate I can only assume that the fan speed will be reduced along with the compressor speed.

    To me this is sort of cheating if a system is designed to NOT be able to run at it's MAXIMUM capacity which accoring to the chart this system is unable to do at temps in excess of temps as low as 90* plus... Of course your going to get a great SEER rating if your system is "limited". Maytag has a video on YouTube that explains the Varieable drive motor comparing it's effiency with that of a car with cruise control. If we were to take that same analogy and apply it to the in-ability of the system to ramp up to maximum speed during the hottest ambient air temps, it would be equilivent to buying a car which would be capeable of doing 55 MPH in residential areas and only capeable of 35 MPH when ever it approached a Freeway. Sure you will get great gas milage because you A) Will not be going 55 in a residential area (or atleast I hope you wouldn't) and B) Youd be going slow in the interstate without stopping.

    However if you only travel at 35 MPH on the Freeway you'd get runover by normal traffic speed. Very much the same as the outside heat over running the CFM of the fan and lower speed compressor at high tempatures.

    If I am understanding this right it just does not make sense. When I asked my rep he called Nordyne and told me thy said that in higher temps the system does not have to work as hard thus it is only required to run in "intermediate mode". They said the once the system was installed and it did not "keep up" Nordyne reps would fly out from Missouri and replace the system with any system I wanted.

    I am not trying to seel my rep short here and he did not say that the attached document was propritary to Nordyne so I see no problem with asking the question... If anyone has info on the New May tag 23 SEER 5 Ton AC I would greatly appreciate it.
    Attached Images Attached Images

  2. #2
    Additionaly attached is the Maytag 16 SEER Model CSA4BF-K(A,B) Series Techinal chart as a comparison which DOES show CFM in addition to it's capeability to run at maximum speed under hotter temps....
    Attached Images Attached Images

  3. #3
    Join Date
    Dec 2007
    Location
    houston, texas
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    3,787
    Personally I think a lot depends on the building envelope, how tight it is and how well insulated. The 23 seer is very expensive up front and not without it's share of issues. Have installed 3 systems and had some issues with each although nothing major yet.
    I'm not tolerating Political Correctness anymore, from now on it's tell it like it is.

    Veto Pro Pak - The best tool bag you'll ever own






  4. #4
    Thannk you Texas Tech for reminding me about the envelope!

    The house was built in 1988 / 1989 by Pardee homes. They appear to have skimped on everything and I am now addressing those issues.

    The house is approximatly 2349 Sq Ft. 2 story. The lower level is open only divided by the stairs and the kitchen behind the stairs. The upper level consists of 4 bedrooms and 2 bathrooms all at the back of the house.

    Windows are single pane though I have taken steps to make them more efficient. I have outfitted the entire upstairs windows with Haylecon Shades which reduce heat gain. I have tinted all the upstairs windows with reflective heat gain tint and applied thermal curtains. There has been a significant heat reduction since the introduction of these items as compared to before when Aleve Gel Capsules melted in their containers and the varnish on new furniture recently purchased began to melt on a dresser when objects were left on it!

    In addition the master bedroom has a vaulted ceiling with no attic. Heat would transfer right in. I cintacted a roofing company and had Low E radiant barrier applied across the entire portion of the roof above the master bedroom. Now it is the coolest room upstairs.

    The rest of the upstairs is under the attic. I have had 2 30 Watt 1500 CFM Solar Attic Fans by Natural Light installed. Attic temps have dropped 30 to 35* respectively and are just outside of 1* difference of outside ambient air temperature. I am hoping cooler attic temps will help the AC system and not make the AC work so hard. In the near future I will be outfitting the attic with Low E radiant barrier attic foil both on rafted and attic floor (floor foil is perforated to allow moisture to pass through) and applying radiant barrier to the rest of the roof which does not have an attic and is vaulted as well as address the downstairs windows.

    The walls are fairly insulated but it is not economically possible to have the walls wrapped. I intend to have a home energy audit conducted to address leaky wall sockets and such. Eventually have the whole ceiling sealed

    The ducting is in that attic and in fairly good shape but has never been cleaned. Though well insulated the return for the AC is located right by the front door and is sharing the wall space. My AC rep will address this by moving the return to a different wall further within the house. The ducts will be cleaned prior to the install of the new system.

    The issues I have found online so far with the IQ drive is the card goes out due to fluxuation of electricity. My understanding is that it is a DC system converted from AC. With that said I would think that installing some capacitors inline with this system should help perhaps in the 20 Farad range? Also being that it is a DC driven system I am surprised that they have not added a module such as Lennox has to make it able to run off solar without the need for the efficacy loss of the internal AC inverter. DC to DC would work exceptionally well with this system because there essentially would be no efficiency loss. For a grid tied system the only requirement of the AC inverter would be at night when power has to be drawn back from the grid.

    Were the issues you encountered electrical or mechanical if I may ask?

  5. #5
    Join Date
    Dec 2007
    Location
    houston, texas
    Posts
    3,787
    The problems I had were all due to failure of different parts such as transformers and limit switches. One thing I did notice was the actual construction of the unit didn't seem to be up to snuff.

    What part of the country is the home in?
    I'm not tolerating Political Correctness anymore, from now on it's tell it like it is.

    Veto Pro Pak - The best tool bag you'll ever own






  6. #6
    The home is in Lake Elsinore CA. The temps are similar to those of Palm Desert CA. Could surge / spikes be the reason for the Transformes failing?

  7. #7
    Join Date
    Jan 2007
    Location
    USA
    Posts
    13
    The airflow created by the condenser fan motor is necessary to reject heat from the ac unit coil into the air.
    The ratings chart show 'X' (meaning outside unit capability) at high ambient temperatures because the ambient air is to hot and too thin to hold the amount of heat generated by your load.
    Or, the amount of heat in your condensing unit at high outdoor temperature is too much for the condensing unit fan to draw out of the system. The refrigerant temperature will remain too high and the result will be compressor trips (alarms) on high head pressure.

  8. #8
    Thank you Desuperheater for your explanation. I appreciate your response. So the system is indeed "limited" and my understanding is that the compressor talks to the fan motor inside the home and lowers it's CFM a the same time or is this not the case?

  9. #9
    Join Date
    Dec 2007
    Location
    houston, texas
    Posts
    3,787
    It is a communicating system, when there is any kind of a problem the first place you go to is the controller. All system info is there, comp rpm, temp etc, fan rpm, it's the starting point for diagnostics.

    I wouldn't think your temps would be that dramatic in Calif, could be wrong.
    I'm not tolerating Political Correctness anymore, from now on it's tell it like it is.

    Veto Pro Pak - The best tool bag you'll ever own






  10. #10
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,025
    A major concern of mine with variable speed compressors is returning oil to the compressor.

    Especially if the evaporator is much lower than the condenser/compressor, it takes a certain vapor velocity to bring oil on inside of pipes back to the compressor; I'd like to know how they handle that situation when vapor velocities would be dropping so low.

    How do they pipe those refrigerant lines on differing applications to achieve proper oil return on IQ systems?

  11. #11
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    799
    Quote Originally Posted by udarrell View Post
    A major concern of mine with variable speed compressors is returning oil to the compressor.

    Especially if the evaporator is much lower than the condenser/compressor, it takes a certain vapor velocity to bring oil on inside of pipes back to the compressor; I'd like to know how they handle that situation when vapor velocities would be dropping so low.

    How do they pipe those refrigerant lines on differing applications to achieve proper oil return on IQ systems?
    Nordyne iq drive periodically runs at 118% nom cap as a oil return feature. The iq stuff is great... If u know how to put it in

  12. #12
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    799
    Wow, didn't know it got that hot. Iq systems shut off if they see outside temps of 125 or higher, it probably wouldn't be a good choice

    That's read at the unit so it will pick up radiant heat from the condenser

  13. #13
    Join Date
    Jan 2010
    Location
    Surprise, AZ
    Posts
    271
    I personally would stick with a carrier, Goodamnan or mabey a trane unit.


    Carriers green speed is coming out i think that might be worth a try. Not sure what your budget is but i would by a 15 or 16 seer unit from goodman and have it installed.


    I would find a Good contrator that knows what he is doing and stands behind his work.

    I would have an energy audit done on the house and have then do a blower door test.


    Also air flow is very inportant too, so if you have duck work that is restrictive to the system then u will want to have that addresed as it will cause the effciancy to diminish.


    If it were me i would stay away from the Iq drive system due to the amount of people who know the system and im sure if you buy mid grade and not top of the line seer you might save enough to purchase another unit in 12 years.

    just my two cents!

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