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  1. #1

    Is Carrier 59MN7A060... really a modulating furnace?

    I am looking at installing a Carrier furnace: 59MN7A060V17-14.

    The product booklet says ‘Fully Modulating Gas Valve — When paired with the InfinityR control, this furnace improves comfort by adjusting heating output in 1% increments from 40% to 100% capacity to meet the heating needs of the home.’

    'M' in the furnace model number stands for modulating but this 'When paired with the InfinityR control' has me 'worried'.

    Is the furnace modulating only with this control?

    The contractor told me the control would cost extra, the improvement in efficiency would be negligible and the furnace would be still modulating without it.

    I would like to confirm it.

  2. #2
    Join Date
    Jan 2004
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    Lancaster PA
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    I believe its only 3 stages without he Infinity controller.
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  3. #3
    Join Date
    Feb 2010
    Location
    Metro Atlanta, GA
    Posts
    475
    From the installation guide

    "A single stage or two--stage heating and
    cooling thermostat can be used with the furnace. The furnace control board CPU will control the furnace and outdoor unit staging. A two stage heating and cooling thermostat can also be used to control the staging. However, full modulating capability will not be available when the furnace staging is controlled by the thermostat. Furnace staging will be limited to Minimum and Maximum inputs or Intermediate and Maximum inputs depending
    on the configuration of set-up switches SW1-2 and SW4-2."

  4. #4
    Join Date
    Nov 2004
    Location
    SW FL
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    6,271
    EVEN brochure say$ Infinity control required.
    So, pay for the Infinity Control.

    http://www.docs.hvacpartners.com/idc...858-581-25.pdf

    The problem is it seems to have been written by a lawyer.

    "Our modulating gas valve helps the Infinity 98 efficiently
    deliver the ideal heating capacity for current conditions
    when the Infinity control is included with your system.
    By continuously adjusting heating output up and down
    through multiple stages in 1% increments, this furnace
    precisely matches your comfort needs. Most other
    furnaces can provide only one or two stages of heating
    and must start a new heating cycle to reduce heating
    capacity as conditions change."
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  5. #5
    Thank you for the answers.

    I got offers from a other contractors and all of the furnaces were 2 stage (Trane, American Standard, KeepRite). I was surprised that the modulating Carrier 59MN7A… was not more expensive than the competitors’ and I wondered why would anyone go with a 2 stage furnace?

    I don’t mind paying more for better efficiency? But I do mind paying even 1 penny more if the furnace does not do what I was told it would do.

    ‘The problem is it seems to have been written by a lawyer.’ So true .
    59MN7A has the ‘M’ for modulating, but it is not unless this control is added, they should specify this very clearly.

    Now I don’t know to believe about the contractor I was very much inclined to go with.

    1. Either he did not know – even if he should – that the 59MN7A… is not modulating without the control so unknowingly he tried to sell me functionality that couldn’t be achieved. I would kind of ‘accept’ it and let it go if this was the case.

    2. This was a marketing ploy to buy a more expensive one as in he (i.e. me) would not mind paying $ more than the quoted 2 stage Carrier 59TNA6A for the perceived extra efficiency but I would lose him as a customer if I asked extra $ (the controller is around $). And in this case I would not want to work with them. Tell me frankly all the options and let me choose but don’t play ‘tricks’ on me.

    And once installed I would not have been in a position to determine whether the furnace is modulating or not.
    The contractor told me that most of their clients go with the 5MN7A but I am sure they have no idea that their furnace is not really modulating as they do not have the controller. And I wish I was like them. The less you know the happier you are .
    Last edited by beenthere; 12-23-2012 at 11:12 PM. Reason: prices

  6. #6
    Join Date
    Dec 2002
    Location
    Houston,Tx.
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    15,907
    Quote Originally Posted by CurbYourEnthusiasm View Post
    And once installed I would not have been in a position to determine whether the furnace is modulating or not. The contractor told me that most of their clients go with the 5MN7A but I am sure they have no idea that their furnace is not really modulating as they do not have the controller. And I wish I was like them. The less you know the happier you are .
    Maybe this is the contractors motto "what the customer don't know don't hurt me"
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  7. #7
    Join Date
    Jan 2004
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    Lancaster PA
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    Prices are not permitted here.
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    How many times must one fix something before it is fixed?

  8. #8
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,040
    The best control of anybody's top system is their matching thermostat. Trane's will modulate but only by timer on a basic thermostat. Rheem's will become a timed 3 stage, only modulates with their special stats. If you don't want to buy the Infinity control, get a 2 stage furnace and a 2 stage stat for lots less.

  9. #9
    Join Date
    Jul 2001
    Location
    Gold Coast of Connecticut
    Posts
    4,578
    Even with a single stage thermostat most modulating furnace do modulate and work very well.

    We install many on old zoning systems that are single stage and I am always surprised how well the built in logic works even with zoning.
    Aire Serv of SW Connecticut- Gas heat, dual fuel and central a/c systems installed and serviced

  10. #10
    Join Date
    Jan 2009
    Location
    Keokuk, IA
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    5,520
    S without a communicating thermostat a a modulating furnace will modulate up on a timer but won't modulate back down and hold a steady for rate. A 2 stage furnace with a good 2 stage thermostat will stage back down to 1st stage and remain there.

    I think there are very few circumstances where you wasn't an infinity furnace without Assn infinity control. Better to stick with the performance series.

    Sent from my DROID RAZR using Tapatalk 2

  11. #11
    Called Carrier - yes, this is how I spend the day after Christmas - and they confirmed that I would need the control to make the furnace ‘modulate’. The 1st CSR could not answer to my question so I was transferred to a senior CSR who in fact read from the product data that I also had.

    However, now after talking to Carrier I know for sure the Infinity control is a thermostat. I had thought before it was something you install on the furnace itself not something that replaces the thermostat (programmable or not) that you put it up the wall.
    My idea was to just install the furnace without this control and later on add the control as now I know that the ‘M’ in 59MN7A stands for ‘Can Modulate’ not ‘Modulate’ but the CSR told me to put it this at the beginning as to make sure everything works ok.

  12. #12
    Join Date
    Nov 2004
    Location
    SW FL
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    6,271
    Quote Originally Posted by CurbYourEnthusiasm View Post

    Called Carrier - yes, this is how I spend the day after Christmas -
    and they confirmed that I would need the control to make the furnace ‘modulate’.
    The 1st CSR could not answer to my question so I was transferred to a senior CSR who in fact read from the product data that I also had.

    However, now after talking to Carrier
    I know for sure the Infinity control is a thermostat.
    I had thought before it was something you install on the furnace itself not something that replaces the thermostat (programmable or not) that you put it up the wall.

    My idea was to just install the furnace without this control and later on
    add the control as now I know that the ‘M’ in 59MN7A stands for ‘Can Modulate’
    not ‘Modulate’ but the CSR told me to put it this at the beginning as to make sure everything works ok.
    So after EIGHT (8) confirmations ( & rereading same sheet), it's Clear that it takes a Specific Thermostat to modulate,
    +
    You get what You pay for!

    I guess now the issue is to
    find a Carrier contractor who knows how to install a Specific Thermostat.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  13. #13
    Join Date
    Dec 2012
    Location
    Westerville, Ohio, United States
    Posts
    24
    This is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

    You can find the rules for posting and qualifications here.

    Further infractions may result in loss of posting privileges.
    Last edited by beenthere; 12-29-2012 at 01:13 PM. Reason: Non Pro * Member

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