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Constant flow systems do not require a bypass. Variable flow systems do.

Calculate the heat load. There are books that help with knowing how to do it. Size for slightly more cooling than needed.

Compare readings with a duct traverse. In residents stable airflow at any location is the hardest thing to find. Airflow readings at diffusers in many cases vary more than you like, even with top...

Artrose is right this is an odd ball system. That is why my comment was limited. To know how it should be designed we need to know what the fans need to do.

This type of system should use the variable speed fan to maintain a constant static pressure.

You got a lot of sound advice. That is normal here. I can only add that to me if a job doesn't present a challenge you enjoy it isn't worth doing. If you think the same, and it appears to me you do,...

I agree with Artrose. Controls should be a natural and would be a career change within your present level of expertise. Learning test and balance would help your understanding of how the controls...

Hire a balance contractor and watch what they do.

Based on your stated level of responsibility all you have to do is tell the chiller supplier to get their tail out there and make the building comfortable. Tell them if they want paid they have to...

Leaving water is too high.

We can't answer that without all the pertinent information. You should have the engineering data.

Good explanation Lahrs.

You are wrong seee. Per your statement the pressure at any point on a pressurized system would be the same except maybe the pump inlet and outlet and it isn't.

You need to include pressure drop as a result of flow.

I've seen some bad situations BBeerme but nothing screwed up that way. It had to take forever to get the air balance completed. Good job!!

One piece of advice sw21 keep calibration of your equipment up to date. I'm not saying you haven't just a reminder.

[QUOTE] We need to pass on accurate information, and unfortunately a lot of this stuff is not easily learned from books, or by simply talking about it......

Much of this requires hands on with a...

The first thing I did was drive all the boxes to full cool because I wanted to traverse the main duct first. If low on airflow I drove the freg drive to where ever needed above 60 hz to determine if...

Artrose You gave him as good advice as I can. There is too much to cover to advise him in this thread as to how balance should be done on a VAV system. He has to calibrate the VAV's and how to do...

This guy sictech will eventually be worth something. A good start was calling you for help and he followed that up by admitting you were right. Help him when he needs it and you will both come out...

They are pretty as long as they hold.

I had an excellant reputation for doing good design work. One lead engineer tried to set me up. He called a meeting with me and the project engineer to review my design about half way through the...

I was a mechanical design engineer for 25 years. I learned to despise most engineers. I worked as a steel fitter prior to deciding I wanted to become an engineer. By tack welding the steel as I put...

I have really enjoyed talking to you BBeerMe. I have been retired long enough that my stories are from the past but I'll gladly share them with anyone that will listen. I also enjoy you guys stories...

If you are talking to me BBeerme you or anyone else here can call me anytime.

I wouldn't run if a bear was going to get me. I'm in good enough shape but would forget to think of it.

Check the pump curve submittal for characteristics. It will tell you the NPSH needed.

The test is right out of the study guide. If you don't understand any part of a question ask the moderator to explain.

There are small pitot tubes that have connections for both tube sizes. You can't accurately pitot traverse a flex duct.

Considering your stated goals a BS degree in mechanical engineering is the best bet. After graduating get a job with a consulting engineering company. You should be good at not only equipment...

As you know the purpose of the dampers is to restrict airflow to within design parameters. By collapsing the flex duct you can do the same thing. You collapse the flex by crushing it the amount...

I hesitated telling you how to balance this because it's best done by someone with balance experience. If you do this don't hurry and don't over adjust.
We used chicken chokers (band straps) on the...

Measure the airflows with a flow hood and adjust the individual diffuser dampers to obtain diffuser airflow to within +/- 10% of design airflow.

I have a friend that wanted to get a degree in mechanical engineering. He had trouble with what most of us thought were the easiest courses. Yes he flunked some of them but give up was not in him. He...

Don't be nervous. Liking the work indicates you are good at it so far. Be confident and the nerves will all but go away.

These systems can work well but are often not set up (calibrated) properly. I balanced a courthouse several years back that had never worked right since installed. I was called to balance it after...

I'm retired and old but enjoy this site. My skills and knowledge haven't kept up with the times and as a result my participation has decreased. There are a lot of sharp techs here.

The subject of being a good teacher deserves it's own thread. I taught a lot of young engineers and loved every minute of it. They liked having someone they trusted to look to when they needed help.

I have worked with a lot of Taco pumps etc. but not familiar with this one. Having said that there are ways the pump can be feed enough info to control total flow but the system is not self...

Those that take liberties with definitions don't change the true meaning of words. Tertiary is a British term that has a specific meaning. If the pump is not the third in order it isn't tertiary. Has...

In the design world primary/secondary is clearly defined. Not saying you are wrong because it is common for some to take liberty with definitions. Tertiary because of the meaning can correctly be...

Tertiary means third in order. That should be a clue as to what pumps can be called tertiary. This thread can get interesting.

I argued with engineers when doing design and when doing TAB. You can only reason with 1 out of 50.

He had more OA than the system could heat at zero OA temperature. I suggested they add carbon monoxide control to the AHU'S and make building static pressure control permissive to that. If they...

Simple design error VTP99 that the engineer didn't want to admit and tried to blame me for when it happened.

I didn't mention the design and/or installation problems you can encounter so I'm glad Artrose did. I didn't want to make this anymore involved than it is but, in my words it's simple but complex....

I'm reluctant to get too far into this because there are several parts of this process that I have seen several TAB certified techs screw up. You start with what is the duct designed to handle. Then...

You got some good comments but get someone to help you on site or you will either fight this for a long time or set the static pressure higher than needed and waste energy or worse. This is not...

I no longer have a dog.

I looked out in my west field and saw a herd of wild turkeys. I thought they knew it was close to thanks giving. They did disappear real fast.