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  1. #14
    Join Date
    Aug 2007
    Location
    MN
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    2,677
    Quote Originally Posted by key1cc View Post
    From your picture "178" it looks like you are suggesting that he take a measurement with the upper panel removed. Am I interpreting that correctly?
    Key1
    yes that's correct, he would put the bottom door back on then and test, the top compartment is separate from the blower compartment.
    You can't fix stupid

  2. #15
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,167
    Yours is easy to do, you got plenty of room in the back.
    Make sure the humidifier bypass is closed when he takes it. Unless you intend to let the damper open when you run the A/C in the summer.
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  3. #16
    Join Date
    Apr 2008
    Location
    Princeton, NJ
    Posts
    581
    Quote Originally Posted by beenthere View Post
    Yours is easy to do, you got plenty of room in the back.
    Make sure the humidifier bypass is closed when he takes it. Unless you intend to let the damper open when you run the A/C in the summer.
    I will keep the damper closed when I run the AC.

    I just hope he does not drill a hole and damage anything inside.

    Key1

  4. #17
    Join Date
    Aug 2007
    Location
    MN
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    Quote Originally Posted by key1cc View Post
    I will keep the damper closed when I run the AC.

    I just hope he does not drill a hole and damage anything inside.

    Key1
    that's why they have the holes there already
    You can't fix stupid

  5. #18
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304




    To me it looks like we have a 100k furnace here?? The duct work on back and front seems awful small for this big of a furnace....?? Does anyone else see this?

  6. #19
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,167
    To me, it looks like 18x10, and maybe 14x10, which would give him a 55* rise at 1500CFM, at 700FPM velocity 100,000 BTU input at 90% eff.
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  7. #20
    Join Date
    Apr 2008
    Location
    Princeton, NJ
    Posts
    581
    Quote Originally Posted by beenthere View Post
    To me, it looks like 18x10, and maybe 14x10, which would give him a 55* rise at 1500CFM, at 700FPM velocity 100,000 BTU input at 90% eff.
    It is a 100k btu furnace (xV95 Trane) with 95% eff.

    There are actually 3 rectangular ducts coming out of the plenum.

    I just measured them and 8x12 comes out the front 8x9.5 comes out the back and 9x12 comes out the top (the one out the top is not viewable in the photos because in runs between the ceiling joists).

    Key1

  8. #21
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,167
    Well, your trunks are a little small for a 100,000 BTU 90%er.
    Your total static is going to be too high.
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  9. #22
    Join Date
    Apr 2008
    Location
    Princeton, NJ
    Posts
    581
    The service and facts sheets that came with the unit included a table that lists static pressures compared to CFM and wattage draw for my unit.

    It states that on my current medium low setting that static from 0.1 to 0.9 will all have 1400 plus or minus 25 CFMs but the wattage draw will increase by about 80 watts for every 0.2 increase in static pressure. The wattage draw starts at about 300 and goes up over 600.

    Hopefully the bypass humidifier helps lower it a bit.

    When I get my static pressures later this week it will give me insight on my options such as should I still pursue the 5" media filiter installation over the current 1"

    Another question, Can the system be set to run on stage 1 all the time and would that help lower the static?

    Key1

  10. #23
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,167
    You may get 1400 CFM at .9" static. But your motor is running high RPMs to do it, and it doesn't allow much of a load up on the air filter. Some where after 1.2" static, the life span of the VS motor becomes shortened.
    So if on a clean air filter you .9", you be wanting to change your filter real often to keep from killing the VS motor.

    Relying on the bypass to keep the static reasonable is not a good thing to do.

    Yes, second stage can be disabled. But that will bring your heat output down to 58,500 BTUs. Will that be enough to heat your house at design temp.
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  11. #24
    Join Date
    Apr 2008
    Location
    Princeton, NJ
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    581
    Quote Originally Posted by beenthere View Post
    You may get 1400 CFM at .9" static. But your motor is running high RPMs to do it, and it doesn't allow much of a load up on the air filter. Some where after 1.2" static, the life span of the VS motor becomes shortened.
    So if on a clean air filter you .9", you be wanting to change your filter real often to keep from killing the VS motor.

    Relying on the bypass to keep the static reasonable is not a good thing to do.

    Yes, second stage can be disabled. But that will bring your heat output down to 58,500 BTUs. Will that be enough to heat your house at design temp.
    My 1st stage has 65k btu output and my installer indicated I would need 75k according to the manual J (which he claimed he did but never let me see it).
    He said the 100k unit would be running in stage one most of the time.

    Key1

  12. #25
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,167
    If your furnace is a 100,000 BTU input. Your first stage input is 65,000 BTU. (65% of 100,000)
    Muiltiply that by .9, and you get 58,500 BTUs output.
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  13. #26
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Another question, Can the system be set to run on stage 1 all the time and would that help lower the static?
    Why would you want to do that if you paid good money for a TWO stage furnace??



    How many sq ft is the home, and where are you out of?

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