Page 1 of 8 12345678 LastLast
Results 1 to 13 of 95

Thread: Petition

  1. #1
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    8,894
    Post Likes

    Petition

    Anyone interested in petitioning for a T&B forum on this site?
    As there are a number of forums here that don't get accessed much at all it seems that as there are many posts concerning T&B, it would probably be popular.
    It's an area that's ignored even though many posts ask for help about T&B.
    I know it's come up in the past but wasn't acted on by Dad.
    Give me a relay with big enough contacts, and I'll run the world!

    You can be anything you want......As long as you don't suck at it.

    If a person wants to create a machine that will be more likely to fail...Make it complicated.

    USAF 98 Bomb Wing 1960-66 SMW Lu49

  2. #2
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    8,894
    Post Likes
    Thread Starter
    I guess not???
    Give me a relay with big enough contacts, and I'll run the world!

    You can be anything you want......As long as you don't suck at it.

    If a person wants to create a machine that will be more likely to fail...Make it complicated.

    USAF 98 Bomb Wing 1960-66 SMW Lu49

  3. #3
    Join Date
    Nov 2014
    Location
    Portland, Oregon, United States
    Posts
    525
    Post Likes
    What is t&b

    Sent from my SM-G935T using Tapatalk

  4. #4
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    30,758
    Post Likes
    I think that could be a good idea.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

    AOP Forum Rules:







  5. #5
    Join Date
    Mar 2013
    Location
    Treasure coast, FL
    Posts
    7,800
    Post Likes
    Yeah, it could go right next to the the ductwork educational forum - they'll probably get about the same amount of attention. :grin:

    I'm not saying the task itself is easy, but it seems that the steps to doing the job are pretty basic. Open a damper some over here, close this one a little, adjust this sheave - voila! Balanced/corrected airflow! :grin:

    Sent from my SCH-I545 using Tapatalk

  6. #6
    Join Date
    Feb 2016
    Location
    Louisburg Kansas
    Posts
    3,156
    Post Likes
    The problem with having a T & B forum is every thinks they know all about it. I have 25 years experience as a design mechanical engineer and 20 years experience as a NEBB certified air and water balancer. There was a question on here about determining airflow from static pressure which I responded to. The smart ass response I got when I advised the guy not to use static pressure because it was unreliable stunned me. I wasn't guessing I was speaking from years of experience unfortunately to people who obviously had no experience in T & B. It is also unfortunate that the guy asking the question probably followed bogus advise given here with who knows what outcome. Most of it was from control technicians who have some understanding of the fundamentals but don't have any meaningful experience doing the work. This statement will I'm sure be responded to with examples of how good a job some of you have done with T & B so I will ask one question here that believe it or not almost half of the control techs I worked with didn't know. If you have a 1000 CFM DDC constant volume dual duct VAV box at what value do you set the Max and Min airflows on both decks and why? I hope since I retired this has become common knowledge.

  7. #7
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    8,894
    Post Likes
    Thread Starter
    Quote Originally Posted by shellkamp View Post
    Yeah, it could go right next to the the ductwork educational forum - they'll probably get about the same amount of attention. :grin:

    I'm not saying the task itself is easy, but it seems that the steps to doing the job are pretty basic. Open a damper some over here, close this one a little, adjust this sheave - voila! Balanced/corrected airflow! :grin:

    Sent from my SCH-I545 using Tapatalk
    Your not even close.
    Give me a relay with big enough contacts, and I'll run the world!

    You can be anything you want......As long as you don't suck at it.

    If a person wants to create a machine that will be more likely to fail...Make it complicated.

    USAF 98 Bomb Wing 1960-66 SMW Lu49

  8. #8
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    8,894
    Post Likes
    Thread Starter
    Quote Originally Posted by WAYNE3298 View Post
    The problem with having a T & B forum is every thinks they know all about it. I have 25 years experience as a design mechanical engineer and 20 years experience as a NEBB certified air and water balancer. There was a question on here about determining airflow from static pressure which I responded to. The smart ass response I got when I advised the guy not to use static pressure because it was unreliable stunned me. I wasn't guessing I was speaking from years of experience unfortunately to people who obviously had no experience in T & B. It is also unfortunate that the guy asking the question probably followed bogus advise given here with who knows what outcome. Most of it was from control technicians who have some understanding of the fundamentals but don't have any meaningful experience doing the work. This statement will I'm sure be responded to with examples of how good a job some of you have done with T & B so I will ask one question here that believe it or not almost half of the control techs I worked with didn't know. If you have a 1000 CFM DDC constant volume dual duct VAV box at what value do you set the Max and Min airflows on both decks and why? I hope since I retired this has become common knowledge.

    I understand what your saying. I too am certified T&B since 1985. For those that think T&B is easy proves they are ignorant of the science behind it. I know the smart a$$ remarks seem to appear in lots of places but that's the internet.
    What had me post this question was to see if there is any interest because of how many questions come up that apply to airflow and some wet side issues also. A recent post had 3 out of 4 pumps running and asked how running the forth pump would effect the pressures.Stuff like that come up all the time.
    An understanding of the problems of using static pressure to determine air flow could be helpful especially for those that think a fan curve is telling the truth. An explanation of how those curves are developed might change how a system is approached as far as problems go.
    With being certified you could offer explanations for problems that would not be a hip shot like so many are. Like shellkamp posted above illustrates the lack of knowledge T&B has in general and what a great tool T&B is.
    I'm sure you as I have seen a building suffering from all things bad concerning air/water balance and how that building does a turn around when a T&B tech applies their knowledge.
    There are a bunch of people working with air flow that don't really know what one CFM is capable of. When I got into this trade I knew what CFM stood for but I didn't know what it could do. Like your example of a VAV box rated at 1000 CFM and asking someone in the trade what can 1000CFM do as far as heat/cool given these parameters. Space size, windows, insulation and all the rest.
    I wasn't thinking of a prep for becoming a T&B tech, just having an understanding of what affects different changes have.
    Give me a relay with big enough contacts, and I'll run the world!

    You can be anything you want......As long as you don't suck at it.

    If a person wants to create a machine that will be more likely to fail...Make it complicated.

    USAF 98 Bomb Wing 1960-66 SMW Lu49

  9. #9
    Join Date
    Mar 2013
    Location
    Treasure coast, FL
    Posts
    7,800
    Post Likes
    Quote Originally Posted by hvacker View Post
    I understand what your saying. I too am certified T&B since 1985. For those that think T&B is easy proves they are ignorant of the science behind it. I know the smart a$$ remarks seem to appear in lots of places but that's the internet.
    What had me post this question was to see if there is any interest because of how many questions come up that apply to airflow and some wet side issues also. A recent post had 3 out of 4 pumps running and asked how running the forth pump would effect the pressures.Stuff like that come up all the time.
    An understanding of the problems of using static pressure to determine air flow could be helpful especially for those that think a fan curve is telling the truth. An explanation of how those curves are developed might change how a system is approached as far as problems go.
    With being certified you could offer explanations for problems that would not be a hip shot like so many are. Like shellkamp posted above illustrates the lack of knowledge T&B has in general and what a great tool T&B is.
    I'm sure you as I have seen a building suffering from all things bad concerning air/water balance and how that building does a turn around when a T&B tech applies their knowledge.
    There are a bunch of people working with air flow that don't really know what one CFM is capable of. When I got into this trade I knew what CFM stood for but I didn't know what it could do. Like your example of a VAV box rated at 1000 CFM and asking someone in the trade what can 1000CFM do as far as heat/cool given these parameters. Space size, windows, insulation and all the rest.
    I wasn't thinking of a prep for becoming a T&B tech, just having an understanding of what affects different changes have.
    Yes I was being a smart a$$, but I don't really think the job is "easy".

    I just think it will end up like the building science or educational forums - nobody seems to be interested in learning the concepts behind anything, just the "tricks of the trade"

    I'd like to see a T&B forum, personally. My cynicism just doubts its success.

    Sent from my SCH-I545 using Tapatalk

  10. Likes hvacker liked this post
  11. #10
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    6,782
    Post Likes
    Maybe it would bring in a more t@b oriented crowd ive done a couple of jobs on start ups going off blue prints, get it close. ...


    The issue lies in for every 1000 capacitor changers their is 1 t&b guy.

    My questions would consist of...

    how close is close enough to appease an inspector?
    6
    How do measure airflow from an economiser without using a fan curve chart?

    How many times do you check each register? I go thru no more than twice.




    Sent from my SM-G550T2 using Tapatalk

  12. #11
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    22,670
    Post Likes
    For me, it doesn't matter if it is DDC or pneumatic, I just set things where the prints say to set them. Because that's what some engineer said to do. And if he or she did their job correctly, then things usually work out pretty good. As the use changes, then we field guys make adjustments up or down from the original design specs.

    If there are no prints, then I just wing it.

    But it could be a trick question. I have worked on dual boxes that were constant volume, and I never considered them to be a VAV box. If you're asking where do you set the min and max on a dual constant volume box, then I'm not sure why you threw VAV in there.


    Quote Originally Posted by WAYNE3298 View Post
    The problem with having a T & B forum is every thinks they know all about it. I have 25 years experience as a design mechanical engineer and 20 years experience as a NEBB certified air and water balancer. There was a question on here about determining airflow from static pressure which I responded to. The smart ass response I got when I advised the guy not to use static pressure because it was unreliable stunned me. I wasn't guessing I was speaking from years of experience unfortunately to people who obviously had no experience in T & B. It is also unfortunate that the guy asking the question probably followed bogus advise given here with who knows what outcome. Most of it was from control technicians who have some understanding of the fundamentals but don't have any meaningful experience doing the work. This statement will I'm sure be responded to with examples of how good a job some of you have done with T & B so I will ask one question here that believe it or not almost half of the control techs I worked with didn't know. If you have a 1000 CFM DDC constant volume dual duct VAV box at what value do you set the Max and Min airflows on both decks and why? I hope since I retired this has become common knowledge.

  13. #12
    Join Date
    Feb 2016
    Location
    Louisburg Kansas
    Posts
    3,156
    Post Likes
    To hvacker I'm really not criticizing you or your suggestion. As you well know calculating airflow using static pressure is in accordance with the fan laws and the fan curve. The catch is measured static pressure is approximate and is the least reliable method of determining airflow which is why as you said values plotted on the fan curve seldom fall where they should. I would love to discuss T & B but without the kind of comments some people like to make. I was a specialist in TAB and was often called in to fix problems others could not. It doesn't bother me if others don't agree but in the case I mentioned the guy asking for the advice in the end stated he was going to use static pressure. He was done an injustice by comments that if made from a stand point of mere opinion would have been OK.
    To BBeerme this is not a trick question. The engineers do not put min airflows on the drawings for these boxes. The boxes are called VAV because they do have variable volume capability even if you chose to operate as constant volume. The dampers on constant volume boxes have the ability to modulate in response to the average velocity pressure measured by the flow ring.
    Again I'm not being critical of anyone's opinion but when you give advice in a forceful manner as if you know the sublect you should be absolutely certain you know what you are talking about.

  14. Likes kdean1 liked this post
  15. #13
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    22,670
    Post Likes
    The units I was working on did have a minimum setting for the cold deck. The hot deck could close down all the way. I just figured it had to do with the fresh air requirement. Since the heating equipment never brought in fresh air, but the cooling side did have fresh air.


    Quote Originally Posted by WAYNE3298 View Post
    To hvacker I'm really not criticizing you or your suggestion. As you well know calculating airflow using static pressure is in accordance with the fan laws and the fan curve. The catch is measured static pressure is approximate and is the least reliable method of determining airflow which is why as you said values plotted on the fan curve seldom fall where they should. I would love to discuss T & B but without the kind of comments some people like to make. I was a specialist in TAB and was often called in to fix problems others could not. It doesn't bother me if others don't agree but in the case I mentioned the guy asking for the advice in the end stated he was going to use static pressure. He was done an injustice by comments that if made from a stand point of mere opinion would have been OK.
    To BBeerme this is not a trick question. The engineers do not put min airflows on the drawings for these boxes. The boxes are called VAV because they do have variable volume capability even if you chose to operate as constant volume. The dampers on constant volume boxes have the ability to modulate in response to the average velocity pressure measured by the flow ring.
    Again I'm not being critical of anyone's opinion but when you give advice in a forceful manner as if you know the sublect you should be absolutely certain you know what you are talking about.

Page 1 of 8 12345678 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •