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  1. #1
    Join Date
    Jan 2008
    Posts
    120

    What is static pressure?

    Guys about got my Infinity furnace system installed and watched the thermostat do a static pressure check.

    Have seen this on several other threads.

    Well what is it? Whats a good number to have?

    Thanks

  2. #2
    Join Date
    Jan 2008
    Location
    Hells Kitchen, Phoenix Arizona
    Posts
    318
    static pressure is exerted on a duct in all directions and is something that velocity pressure(air moving down the duct) has to overcome...The higher the number the lower the airflow...
    "Overkill is an often underrated achievement", Will Hayden -- Red Jacket Firearms

  3. #3
    Join Date
    Apr 2002
    Posts
    11,808
    Quote Originally Posted by Hrdworkingacguy View Post
    static pressure is exerted on a duct in all directions and is something that velocity pressure(air moving down the duct) has to overcome...The higher the number the lower the airflow...
    velocity pressure does not have to over come static pressure

  4. #4
    Join Date
    Jan 2008
    Posts
    120
    Fair enough, thanks

  5. #5

    Cool definition

    Its what I felt when i came home with no roses or chocolates-can lead to cold feet.

  6. #6
    Join Date
    Jan 2008
    Location
    phoenix, AZ
    Posts
    29
    take a five gallon water bottle with a 1/2" hose on the outlet. full of water, and turn it upside down. the amount of water coming out is like cfm. and the pressure in the bottle itself would relate to static pressure

  7. #7
    Join Date
    Dec 2007
    Location
    Oregon
    Posts
    525
    Static pressure is the pressure on the discharge side of your ductwork or fan system. Typically you would measure this with a magnahelic that reads in inches of water column. The high side port would be inserted through the side of the duct.....same as reading the pressure of air inside of a balloon.

    Total static pressure would be the pressure across a fan system or AC unit.
    High side probe would be inserted on the discharge side of the system and the low side inserted on the return or negative side of the system.

    Example 2 inches discharge pressure + .5 inches negative pressure = 2.5 inces total static pressure

  8. #8
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,001

    Question Long Enough ?

    Quote Originally Posted by Pegsmi98 View Post
    Fair enough, thanks
    http://www.udarrell.com/external_sta..._readings.html
    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

  9. #9
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Airflow is likely different between heating and cooling cfms,so both need to be checked.

  10. #10
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,001

    Thumbs down

    Quote Originally Posted by dash View Post
    Airflow is likely different between heating and cooling cfms,so both need to be checked.
    simply ain't gonna happen
    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

  11. #11
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,031
    A good number to have...

    0.5 IWC or less.
    Perhaps you should have read the instructions before calling.

  12. #12
    Join Date
    Jul 2007
    Location
    SA
    Posts
    127
    Quote Originally Posted by chillerfreak View Post
    Static pressure is the pressure on the discharge side of your ductwork or fan system. Typically you would measure this with a magnahelic that reads in inches of water column. The high side port would be inserted through the side of the duct.....same as reading the pressure of air inside of a balloon.

    Total static pressure would be the pressure across a fan system or AC unit.
    High side probe would be inserted on the discharge side of the system and the low side inserted on the return or negative side of the system.

    Example 2 inches discharge pressure + .5 inches negative pressure = 2.5 inces total static pressure
    never seen 2 inches on "discharge" supply side

    the data plate will let you know what to shoot for. checking static pressure should be done every time before checking charge in my opinion.

  13. #13
    Join Date
    Jan 2002
    Location
    Ft.Worth,Tx
    Posts
    4,581
    Infinity system would let you know if the static pressure was to high, because it would shut -down . Most run between .50 and .75 @ the measure cfm of ductwork. Static can be checked with Magnahelic.
    "Everyday above ground, is a good day".
    "But everyday that you have made a difference in someones life, may insure you stay above ground a little longer".<aircooled>

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