Results 1 to 11 of 11
  1. #1
    Join Date
    Jul 2008
    Posts
    433

    "gapping" filter and airflow (plz read for clarification)

    Dont know if "gapping" is the word im looking for but read on. Consider the following; a filter rack with 2 oh say 18X18X1 filters. The return size is pinched down for what ever reason through the wall where the filter rack is. With the filters in place it makes a whisiling noise (yes all that said is a whole issue in itself but one question at a time) bothers the gal in the adjacent office so the staff routinley pulls the filters up to relieve the noise leaving about a 5-6" "gap" between the bottom of the rack and the bottom of the filter. My question is in theroy would (aside from the obvious reduction in return size) this also reduce the airflow since the air would enter in through the 5-6 inch gap of un-filtered space by virtue of the fact that its taking the path of least resistance as opposed to having the filters totally in place? Does that make sense what im trying to say here? Thoughts?
    "It's just like it doesn't work. I mean it seems to be ok now, but it usually like never works"

    "Never an always and always a maybe"

  2. #2
    Join Date
    Jul 2011
    Location
    East coast USA
    Posts
    967
    That gap over time will dirty a coil pretty fast. The whisiling noise could be coming from the air sucking between the filters like wax paper over a comb. In some cases i will use a link filter so you would have a 18 x 36. But you are correct that its not good to restrict return air. I would check the pressure drop with a clean filter and again with out a filter. that will tell you pretty quick you have issues.

  3. #3
    Join Date
    Jul 2008
    Posts
    433
    Much agreed but the partial removal of the filters stops the whistle. My question is does the majority of the air just use that clear unfiltered space say 6x36 since it'll naturally seek path of least resistance rather then using the whole 36x36 return path does that make sense?

  4. #4
    Join Date
    Jan 2003
    Location
    Kansas City
    Posts
    1,482
    you reduce the return static pressure by pulling the filters up. if you are using pleated filters try using standard filters. proper air flow is more important then filtered air

  5. #5
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    If your stacking 2 together and pleated that's not good, try a single 2" thick filter.


    Sent from my iPhone using Tapatalk

  6. #6
    Join Date
    Jul 2008
    Posts
    433
    Quote Originally Posted by james mo View Post
    you reduce the return static pressure by pulling the filters up. if you are using pleated filters try using standard filters. proper air flow is more important then filtered air
    Interesting could you please expand on that
    "It's just like it doesn't work. I mean it seems to be ok now, but it usually like never works"

    "Never an always and always a maybe"

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,048
    It increases air flow.
    Contractor locator map

    How-to-apply-for-Professional

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

  8. #8
    Join Date
    Jul 2008
    Posts
    433
    How does increasing airflow reduce static pressure?

  9. #9
    Join Date
    Jun 2009
    Location
    Upstate SC
    Posts
    1,439
    Quote Originally Posted by dave1234 View Post
    How does increasing airflow reduce static pressure?
    They are one in the same. The filters restrict airflow which increases your static pressure because the blower is working harder to pull air through the filters.



    Sent from my ERIS using Tapatalk 2

  10. #10
    Join Date
    Dec 2011
    Location
    San Antonio, TX
    Posts
    381
    Static measures resistance against airflow. The lower the number, the less resistance.

  11. #11
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Quote Originally Posted by jdblack View Post
    They are one in the same. The filters restrict airflow which increases your static pressure because the blower is working harder to pull air through the filters.



    Sent from my ERIS using Tapatalk 2
    I thought Learned on here it works the same just runs hot from low air flow.


    Sent from my iPhone using Tapatalk

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event