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  1. #1
    Join Date
    Feb 2007
    Posts
    999

    VisionPRO IAQ question

    In the Product Data (.pdf) for the thermostat, it states:

    "INTERSTAGE DIFFERENTIAL:

    VP IAQ comfort systems operate with droopless control. Once the thermostat senses that 1st stage is running at 90% capacity, the thermostat energizes 2nd stage."

    As a home owner, this is confusing. My understanding is that each stage has a 'fixed' capacity. What is being referred to (90% of what)?

    I'll take a guess (probably wrong). Is it when the home's heat loss is equal to 90% of 1st stage heating capacity? Whatever it is, how does the thermostat sense it?

    Thanks.

    AM

  2. #2
    Join Date
    Nov 2004
    Location
    NJ
    Posts
    1,187
    My guess is your guess is correct. And it could be doing it based on previous operating experience.

    We could be 100% wrong though, someone here knows I'd guess.
    Ed J

  3. #3
    Thats kind of what the Intelligence Adaptive Recovery does, other than being used by the programming. It learns the cycles of the system. Also, it should only operate the second stage when theres more than a 3 degree difference or more.

  4. #4
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Honeywell's Vision lines are a learning t-stat, it learns your home's load everyday, and when it see that your heating reaches 90% of it's first stage load, the 2nd stage will fire in and help keep up on a very cold day.

    You will not see any drop in temp on the t-stat reading, it will keep the house's temp close to set point.

    I have one myself, and when we had our -15˚ temps, my furnace pretty much ran non stop in 1st stage, and will cycle in and out of 2nd stage every now and then, the house temp was with in +/- 1˚ in each room from the t-stat in the hall.

  5. #5
    Join Date
    Feb 2007
    Posts
    999
    Quote Originally Posted by mayguy View Post
    Honeywell's Vision lines are a learning t-stat, it learns your home's load everyday, and when it see that your heating reaches 90% of it's first stage load, the 2nd stage will fire in and help keep up on a very cold day.

    You will not see any drop in temp on the t-stat reading, it will keep the house's temp close to set point.

    I have one myself, and when we had our -15˚ temps, my furnace pretty much ran non stop in 1st stage, and will cycle in and out of 2nd stage every now and then, the house temp was with in +/- 1˚ in each room from the t-stat in the hall.
    Thanks. I don't envy your OD temps.

    How about when recovering from a set back (programmed or manual adjustment of TS)? Does the number of degrees make a difference?

    AM

  6. #6
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by ampulman View Post
    Thanks. I don't envy your OD temps.
    Aww come on.. A few years ago, we had -20˚ to -27˚ for a few days.. Things were just starting to stiffen up! :-)

    How about when recovering from a set back (programmed or manual adjustment of TS)? Does the number of degrees make a difference?
    With manual turn of the temp say I am home early where the set back has already taken place, I bump the temp up, the t-stat will fire off 2nd stage right away, and when it's a couple of degrees near my setting, the furnace then will go into 1st stage and slowly bring up the temp, may cycle back into 2nd stage if the t-stat see that 1st stage isn't recovering.

    As for programed set back, as said earlier, it's a learning t-stat, and learns your home everday.. With a cool morning, the furnace takes about 1/2hr to recover, the t-stat will start it at 5:30, and be to temp at 6 when we wake up.

    If it's colder, say 0˚ may take an hour or so, and again it will start off an hour early. The recovery is the same thing as the recovery in manual.

  7. #7
    Join Date
    Feb 2007
    Posts
    999
    Quote Originally Posted by mayguy View Post
    Aww come on.. A few years ago, we had -20˚ to -27˚ for a few days.. Things were just starting to stiffen up! :-)



    With manual turn of the temp say I am home early where the set back has already taken place, I bump the temp up, the t-stat will fire off 2nd stage right away, and when it's a couple of degrees near my setting, the furnace then will go into 1st stage and slowly bring up the temp, may cycle back into 2nd stage if the t-stat see that 1st stage isn't recovering.

    As for programed set back, as said earlier, it's a learning t-stat, and learns your home everday.. With a cool morning, the furnace takes about 1/2hr to recover, the t-stat will start it at 5:30, and be to temp at 6 when we wake up.

    If it's colder, say 0˚ may take an hour or so, and again it will start off an hour early. The recovery is the same thing as the recovery in manual.
    Thanks, I believe you've covered my questions nicely.

    AM

  8. #8
    Join Date
    Oct 2007
    Location
    Toronto
    Posts
    9
    Just had one of these installed and starting to learn how to use it. Basic question...is there anyway for a (non-tech) layman to verify that the contractor properly wired up the unit to work with the humidifier?

  9. #9
    Join Date
    Jun 2007
    Location
    Metro St. Louis
    Posts
    181
    Quote Originally Posted by gevaltech View Post
    Just had one of these installed and starting to learn how to use it. Basic question...is there anyway for a (non-tech) layman to verify that the contractor properly wired up the unit to work with the humidifier?
    Sure - take the humidity setting down to the lowest level (1). Go to your furnace and make sure that there's no water flow (depending upon model, that could be as simple as checking to see that no water flows down the drain).

    Then, turn the setting all the way to the top. Now there should be water flowing.

    Of course, the furnace has to be running...

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