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  1. #1
    Join Date
    Mar 2006
    Posts
    5

    How to tell if two stage heating is two stage?

    This is going to sound pretty stupid, but I can't tell if there really are two stages of heat coming from my unit. I have the Lennox G61MPV, and have checked the dip switches and jumpers and all looks correct for 2 stage operation. However, it seems like whenever heat is on, it is on full. Should I be able to tell a noticable difference from first stage heating vs second stage heating, either in blower speed or air temp exiting the vents?

    Sorry for such a basic question, but it really has me questioning if I'm getting the benefits of a dual stage heating unit.

    Thanks,
    Dave

  2. #2
    Join Date
    Aug 2006
    Location
    Columbus Ohio
    Posts
    2,011
    Hire a professional, it involves gas pressure readings and low voltage control meter readings.

  3. #3
    Join Date
    Jan 2007
    Location
    N.E. Ok.
    Posts
    1,370
    Being a 2 stage homeowner in my spare time, i can tell increas in airflow in 2nd. stage

  4. #4
    Join Date
    Nov 2008
    Posts
    1,673
    "A two-stage furnace requires all or some of the following components: a two-stage gas valve, two-stage controls, a
    multiple speed blower motor, and two-speed inducer motor.

    A two-stage control is any control
    that uses a two-stage adjustment of the furnace input rate in response to changes in the heating
    load. Based on thermostat demand, the two-stage control cycles the burners between a reduced
    heat input rate and off or between the maximum heat input rate and off. "

    I guess if you ask for 1F or 10F above the current ambient you'll the low or high rate.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,113
    It can be hard to determine if a furnace is in first or second stage.

    You may want to try this.

    Turn your heat up one degree above room temp.

    Then go to the furnace, and have your wife turn the stat up another 5 or 6 degrees.
    And see if you hear a change in its operating noise.

    If not.
    Its possible your contractor wired it wrong.
    And you'll just need them to come out and correct the wiring.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Jun 2006
    Location
    New Jersey
    Posts
    4,337
    Quote Originally Posted by beenthere View Post
    It can be hard to determine if a furnace is in first or second stage.

    You may want to try this.

    Turn your heat up one degree above room temp.

    Then go to the furnace, and have your wife turn the stat up another 5 or 6 degrees.
    And see if you hear a change in its operating noise.

    If not.
    Its possible your contractor wired it wrong.
    And you'll just need them to come out and correct the wiring.
    That will work if it has a 2 stage thermostat and has the jumpers set correct. That furnace also has the option of a single stage stat and timed secound stage. Again, you should notice a change in blower speed when changing from 1st to 2nd stage. I would have a pro come out and double check what you have and if the wiring and jumpers are set correctly.

  7. #7
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    You should notice a change in blower speed and the speed of the inducer fan as well as "louder" flame as it increases in intensity.... if it's audible. Some cabinets are pretty quiet. You might also hear the gas valve open to the higher setting.

    The bad news, is that you might have to sit there a while.

    On my unit, it goes from somewhere around 750CFM to 900CFM, so to me it's a pretty noticeable increase in airflow comming form the vents. Although... my humidifier bypass pipe has a damper on it so it also can increase or decrease the air flow by almost 150 CFM.

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