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  1. #27
    Join Date
    Dec 2002
    Location
    Houston,Tx.
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    16,000
    Well if your furnace requires a 3/4 hp motor and he has a 1/3 hp in there, and I can see from here he has it running on the lowest speed in heat mode "red" your in trouble.
    __________________________________________________ _______________________
    “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

  2. #28
    Regarding motor Replacement. No, I did not replace the motor. It was done by an HVAC company in Olathe, KS with "star" in the name. Then they quoted me a cost to replace the entire furnace which after giving me credit for the blower motor replacment was over $ more than the next closest "tentative" bid that I got over the phone when giving specifications to several other companies. The last HVAC tech that came out said that my furnace and heat exchanger was iin good shape. He did a burner cleaning and cleaned up that area of the furnace and said that I was set for the winter. I signed up for their annual furnace and A/C cleanings at the time.
    Last edited by beenthere; 12-30-2012 at 03:26 PM. Reason: price difference

  3. #29
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,000
    Quote Originally Posted by jimdavisjr View Post
    The last HVAC tech that came out said that my furnace and heat exchanger was iin good shape. He did a burner cleaning and cleaned up that area of the furnace and said that I was set for the winter. I signed up for their annual furnace and A/C cleanings at the time.
    So you have had another tech come out since the motor was installed? and he did not address checking out the wiring just to see if it was correct, and he just left the service panel laying on the bottom?

    Was this one of the company's you called?

    __________________________________________________ _______________________
    “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

  4. #30
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Quote Originally Posted by Mr Bill View Post
    So you have had another tech come out since the motor was installed? and he did not address checking out the wiring just to see if it was correct, and he just left the service panel laying on the bottom?

    Was this one of the company's you called?

    Wow that's one funny picture lol

  5. #31
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,989
    Lennox G23 Q3/4 - 125 - 4
    Looks like the air handler is rated to handle 4-Tons of cooling or 1600-CFM.
    At say, 125,000-Btuh output(?) (or Input?) / (temp-rise 70-F *1.1 is 77) *77, (if required temp-rise limit CFM is 70-F; could be 60-F) that is 1623-CFM.

    That blower in heating mode should be operating on high speed &, you said it is on a lower speed. Also, are you using a large pressure drop 1" pleated filter, along with duct system problems, it won't move nearly enough air past the heat-exchanger; possibly not even on high to keep temp-rise, over Return Temp, within 70-F at closest register.

    The replacement motor may not be an exact Original Equipment replacement or accurate cross-referenced motor; also the motor & capacitor may NOT be wired correctly. Seems like the tech may have screwed-up...?

    Twilli is OKAY; JUST A FUN PUN...

  6. #32
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,000
    Quote Originally Posted by udarrell View Post
    Looks like the air handler is rated to handle 4-Tons of cooling or 1600-CFM.
    At say, 125,000-Btuh output.
    Darrell, if that's the case, I know that furnace requires a 3/4 hp motor, and if it has a 7.5 cap, I doubt it's a 3/4 hp probably a 1/3 hp.
    __________________________________________________ _______________________
    “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. #33
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,279
    Quote Originally Posted by udarrell View Post
    Looks like the air handler is rated to handle 4-Tons of cooling or 1600-CFM.
    At say, 125,000-Btuh output(?) (or Input?) / (temp-rise 70-F *1.1 is 77) *77, (if required temp-rise limit CFM is 70-F; could be 60-F) that is 1623-CFM.

    That blower in heating mode should be operating on high speed &, you said it is on a lower speed. Also, are you using a large pressure drop 1" pleated filter, along with duct system problems, it won't move nearly enough air past the heat-exchanger; possibly not even on high to keep temp-rise, over Return Temp, within 70-F at closest register.

    The replacement motor may not be an exact Original Equipment replacement or accurate cross-referenced motor; also the motor & capacitor may NOT be wired correctly. Seems like the tech may have screwed-up...?
    If ID temps is 70, plus a 77 degree rise that's a 147F air coming from the registers. 1,600 CFM of nearly 150F air is a LOT of heat !!!

  8. #34
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,989
    Quote Originally Posted by Mr Bill View Post
    Darrell, if that's the case, I know that furnace requires a 3/4 hp motor, and if it has a 7.5 cap, I doubt it's a 3/4 hp probably a 1/3 hp.
    Yep, Right-On Mr Bill - looks like a real mess...!

  9. #35
    I don't remember if the second tech even opened up the bottom compartmetn of the furnace. But if he did, then yes he did leave it like this. He was there about thirty minutes and cleaned out the burners vacuumed out that compartment and used the flashlight to look around at the heat exchanger. It sounds like maybe I should look for Twilli! LOL

    Seriously, at this point I am thinking that I will call back the company that installed the blower and ask them to take a look at it and fix the problem. I don't understand the technical talk on the temp rise/drop, etc. But it sounds like my motor is either undersized or perhaps is running on low speed when high speed is needed.

    I remember the first tech sitting in the floor studying the wiring diagram on the panel. And he made a comment something along the lines of, "the circuit board must control the fan speeds". Then he finished up the wiring and it seemed to work at the time.

    Mr. Bill says that it will only run on low speed. Is that due to the yellow, brown and blue motor wires being tied together?

    It definitely does not cycle when I turn on the fan full time from the thermostat ... high speed. When the furnace ignites and fires up it only runs at one slower speed.

    BTW, I left the A frame coil panel off just as a check to see if it allowed enough air to pass through the system to prevent cycling. It did not work. I will be putting that back into place. It was only a test.

  10. #36
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,000
    Quote Originally Posted by jimdavisjr View Post
    I remember the first tech sitting in the floor studying the wiring diagram on the panel. And he made a comment something along the lines of, "the circuit board must control the fan speeds".
    __________________________________________________ _______________________
    “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

  11. #37
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,989
    Quote Originally Posted by 54regcab View Post
    If ID temps is 70, plus a 77 degree rise that's a 147F air coming from the registers. 1,600 CFM of nearly 150F air is a LOT of heat !!!
    Right-on CAB, though some of the larger 120,000 Btuh Output furnaces have a 40 to 70-F temp-rise with an absolute temporary MAX outlet temp of 170-F; and the larger 130,000-output, even up to 75-F temp-rise; temporary absolute MAX outlet 175-F.

    Of course, that MAX Outlet-Temp would damage a gas furnace heat exchanger if allowed to continue operating that high...!

  12. #38
    Forgot to mention that the reason I left the panel off of the A frame to test the air flow.

    When we had the basement area remodeled to add more square footage last winter there was some sheetrock dust around for a few days. I was worried that some of it might have collected on the evaporator coil and could be clogging up the flow. It looks pretty clean, but I was not sure if the sheetrock dust would be a problem that might not be too visible.

    The filter is a simple pleated filter that I bought from Home Depot/Lowes type store. It has wire on one that faces the blower. It has a very gentle pleated wave to it. It is not too heavy. It is the smae kind of filter I have been using for years. I don't think that this is the kind of problem filter that is mentioned above.

  13. #39
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,989
    The filter is a simple pleated filter that I bought from Home Depot/Lowes type store. It has wire on one that faces the blower. It has a very gentle pleated wave to it. It is not too heavy. It is the same kind of filter I have been using for years. I don't think that this is the kind of problem filter that is mentioned above.
    Sorry, but that is exactly the kind of 1" thick pleated filter I was referring to, that has a lot of airflow resistance & will lower the air flow CFM...

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