HVAC engineer, 8 years of experience in consulting. Recently moved into construction.

I have been arguing with my manager (who is very much a construction guy, not a consultant) that we cannot install a CAV air handling unit on a system with VAVs and expect it to work correctly. He flat out refuses to listen to me. Myself and HIS boss insist that the AHU needs to be equipped with a VFD to compensate for the operation of the VAVs, he is insistent that this is not the case and that we can still operate a CAV system with VAVs.

Can I get a sanity check here? Am I being gaslit by my manager or have I somehow spent my entire career misunderstanding how AHUs work?

Why do engineers have to do some much marketing in this economy? Is the marketing department that inefficient? What’s going on?

# Intro

​

Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

​

* Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

​

* Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

​

* Feedback on your résumé, CV, cover letter, etc.

​

* The job market, compensation, relocation, and other topics on the economics of engineering.

​

> [Archive of past threads](https://www.reddit.com/r/engineering/search?q=flair%3A%22weekly+discussion%22&restrict_sr=on&sort=new&t=all)

​

---

​

## Guidelines

​

1. **Before asking any questions, consult [the AskEngineers wiki.](https://new.reddit.com/r/askengineers/wiki/faq)** There are detailed answers to common questions on:

* Job compensation

* Cost of Living adjustments

* Advice for how to decide on an engineering major

* How to choose which university to attend

​

1. Most subreddit rules still apply and will be enforced, especially R7 and R9 (with the obvious exceptions of R1 and R3)

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1. Job POSTINGS must go into the latest [**Monthly Hiring Thread.**]((https://www.reddit.com/r/engineering/search?q=flair%3A%22hiring+thread%22&restrict_sr=on&sort=new&t=all)) Any that are posted here will be removed, and you'll be kindly redirected to the hiring thread.

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1. **Do not request interviews in this thread!** If you need to interview an engineer for your school assignment, use the list in the sidebar.

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## Resources

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* [The AskEngineers wiki](https://new.reddit.com/r/askengineers/wiki/faq)

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* [The AskEngineers Quarterly Salary Survey](https://www.reddit.com/r/AskEngineers/search/?q=flair%3A%22salary+survey%22&include_over_18=on&restrict_sr=on&t=all&sort=new)

​

* **For students:** [*"What's your average day like as an engineer?"*](https://www.reddit.com/r/AskEngineers/wiki/faq#wiki_what.27s_your_average_day_like_as_an_engineer.3F) We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.

​

* For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.

Have an electric winch on my boat. Uses small 1/8 rope and 2 ft of 1/8 chain. About 8 inches, or 1 wrap of chain will wrap around rope, on drum in housing, when stowed. I want to add 5 ft of 3/8 chain to the end. Note... A davit is 1 roller to allow anchor line to drop in water off top of bow. Allowing 90° drop, and also holds anchor when stored, keeps it from swinging in the wind.

Can I install 2 statationary pulleys to more or less, store 3/8 chain, make up the difference in length of new 3/8 chain, keep the 3/8 from winding on my rope drum ?

Instead of running in a straight line, from winch to davit, I'll have,

1 pulley in front of winch, where davit is now. 1 pulley next to winch. Move davit to in front of 2nd pulley, to the tip of the bow.

I'll have an " N shaped path. Winch and davit for anchor, would be mounted at each point on the "N". The 2 points of diagonal line on the "N" would be stationary pulleys. Which would "store" larger 3/8 chain. Allow 1/8 chain and rope to pass thru rollers.

Would that affect lifting capacity ? If...proper chain roller pulleys are used. I'm not introducing mechanical advantage, or snatch blocks, only using pulleys to allow a bigger chain at the end, between current 1/8 chain and anchor. Increase distance between Davit and winch drum. I DO have a basic drawing, but didn't know how to post a picture in this post. Will this work ? Thanks !

Any tips or guidelines for designing a facility with a self destruct sequence? I've scoured the local and national codes and can't find anything. Has to be ADA compliant too. I've reached out to local demo contractors to determine where the charges should be placed already to provide space in the walls to make sure the architect is pleased with the way they look.

Specifically looking for timer length recommendations.

I'm a tradesperson turned mechanical technologist. I work in design for a late stage startup. Our shop floor and tool situation is... Chaotic. I joined up the the terminal phase of a failed 5s environment, where it’s too late to save it without chucking it all and starting over. Plundered drill indexes, wrenches disappear, etc.

I'm from a shop floor background, I've been a part of and know what a successful 5S environment for production looks like. I know what works when it’s all trades and production cells, but an R&D environment is different. More fast paced, more variety, it’s much much harder to begin the 1st stage of a 5S, the “sort”. We need a wide variety of hand, power, fabrication and measuring tools available in a fairly unpredictable pattern.

Our main issue is tools disappearing. My usual approach to that is to “flood” and “identify”. People steal tools when they can’t find what they need, and don’t return them when they both forget to return, and forget where the tool came from.

I want to have enough tools to have them readily available, and have the tools so obviously identifiable that you can see from 10 feet away if that tool needs to go back to its home.

I don’t like tools in drawers. I want to see everything fast. If I can’t find my tool, as someone new, in less than 15-30 seconds, it’s a failed system. The problem here is 5S boards aren’t usually very dense, without putting incredible amounts of work into a careful layout that inevitably becomes out of date when your tool requirements change. Maybe a “see through” drawer? Does that exist?

So how do I solve the 2 main issues:

1- Storage in a visual shadowboarded way for large amounts of unique tooling,

-Multiple vertical leaf through panels? Like they used for flipping through posters

• I am not a fan of the traditional pegboard. The hooks fall out and the board falls apart too fast.

  -I actually like screws or bolts in thick plywood, but that has lots of other issues. Main advantage is easy to reconfigure.

  -Shadowboard tracing I have had luck with simple paint marker outlines. The main problem with shadowboarding is it is so labour intensive to setup.

2- Tool identification. -words are not obvious enough

-tape doesn’t last

-spray paint is ugly (but an option)

-I’ve seen nail polish enamel used with success

I’m just hoping for some examples and advice here… A pretty shadow board example where they have pliers, cutters, a wrench set, and a couple sockets isn’t going to cut it.

Any tips on how to go about learning PV Design.

I been digging thru a bit but havent structured in compress.

How much can we expect to lesrn in the firdt year. Im 6 months in and want to show some progress.

Hi folks, I have a vessel working at mawp. I am a little worried about overpressure. By law, does this require a PSV?

The code is a little confusing for me.

Hi everyone, I am designing a system where I need to measure flow in order to regulate it close to but not exceeding 0.5gpm. I already have the flow regulator I will use the McMaster-Carr precision flow adjustment valve 1/4 inch with a 0.51 max flow coefficient (https://www.mcmaster.com/46425K12/).

In order to measure precisely the flow so I stay close to 0.5gpm I am considering using the Swissflow low pressure flowmeter, (https://www.daitron.com/sf-800) since it is the only reasonably affordable flow meter I could find that is able to measure flows under 3gpm.

I am trying to keep the design as simple and affordable as possible. This will be an external standalone design.
What display could I use with the Swissflow flowmeter in order to get a reading? Would the display be enough to get it to function?

Am I over-engineering this? Is there a simpler solution for staying close-to but not exceeding 0.5gpm?

TLDR: What display could I use with a sf-800 Swiss flow flowmeter?

any feedback is appreciated 🙏

# Intro

​

Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

​

* Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

​

* Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

​

* Feedback on your résumé, CV, cover letter, etc.

​

* The job market, compensation, relocation, and other topics on the economics of engineering.

​

> [Archive of past threads](https://www.reddit.com/r/engineering/search?q=flair%3A%22weekly+discussion%22&restrict_sr=on&sort=new&t=all)

​

---

​

## Guidelines

​

1. **Before asking any questions, consult [the AskEngineers wiki.](https://new.reddit.com/r/askengineers/wiki/faq)** There are detailed answers to common questions on:

* Job compensation

* Cost of Living adjustments

* Advice for how to decide on an engineering major

* How to choose which university to attend

​

1. Most subreddit rules still apply and will be enforced, especially R7 and R9 (with the obvious exceptions of R1 and R3)

​

1. Job POSTINGS must go into the latest [**Monthly Hiring Thread.**]((https://www.reddit.com/r/engineering/search?q=flair%3A%22hiring+thread%22&restrict_sr=on&sort=new&t=all)) Any that are posted here will be removed, and you'll be kindly redirected to the hiring thread.

​

1. **Do not request interviews in this thread!** If you need to interview an engineer for your school assignment, use the list in the sidebar.

​

## Resources

​

* [The AskEngineers wiki](https://new.reddit.com/r/askengineers/wiki/faq)

​

* [The AskEngineers Quarterly Salary Survey](https://www.reddit.com/r/AskEngineers/search/?q=flair%3A%22salary+survey%22&include_over_18=on&restrict_sr=on&t=all&sort=new)

​

* **For students:** [*"What's your average day like as an engineer?"*](https://www.reddit.com/r/AskEngineers/wiki/faq#wiki_what.27s_your_average_day_like_as_an_engineer.3F) We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.

​

* For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.

Hi everyone,

I’m currently working on a project involving PLS-Tower for the analysis of transmission line structures. A significant part of my work includes creating and managing Angle Group files, but manually inputting this data is quite time-consuming.

I’m looking for ways to automate the creation of these files using tools like Python or any other scripting language. Here are the key points I’d like advice on: 1. Is it possible to automate the generation of .pls or .lca files for Angle Groups? 2. Are there specific formats or requirements I need to follow for PLS-Tower to accept these files? 3. Has anyone here worked on similar automation tasks with PLS-Tower and could share examples or useful resources?

I’d appreciate any suggestions, documentation, or guidance that could help me move forward on this topic. Thanks in advance for your help!

Best regards,

I work for a tech start-up. We have teams whose work is composed of administrative, labor-intensive, manual work. Our engineering team is working on ML and automation models to alleviate the need for humans to do this work. Some of the engineers are anxious that the work they are doing will eliminate the need for their co-workers jobs on the other teams. Have any of you felt this way in your jobs, i.e. that your work might mean fewer employees are needed and you are torn/anxious about that? If yes, what has helped you work through this?

I am designing something that will probably use a roller chain with extended pins on one side only to actuate something, but I have never worked with extended pin roller chains before (also not had much to do with roller chains either).

As the force is on one side of chain and therefore induces a moment on the chain along the rigid axis, it seems that there should be some special design considerations that need to be made, but I'm not found anything.

Google has not been much use (not that's it's good these days) and I've tried looking at the manufacturers guides and catalogues hoping for some starting place, but not everyone carries them and those that do don't seem to include any special data specific to them. I can't even find things like basic maximum load data for double sided extended pins!

I'm hoping someone might be able to point me the right way.

Solidworks or Inventor?

Hello, my boss wants me to build a system I'm not very confident with. He has pictures from his previous job where they had a RBF inside a residential microwave with a condenser attached coming out through a hole drilled into the lid of the microwave. Supposedly that ran fine for a while without issue. Before I joined, he had another facility within our org make one without the column but with a glass thermometer instead and that worked (though the operator said using the thing always scared him). I've found two papers that use this method in a similar application but neither mention how to set up the microwave.

I tried setting this up but whenever I run the microwave it'll shut off in 2-30 seconds, occasionally giving me one of a few error codes. There's no documentation for this $55 Walmart microwave but I suspect it's shorting out various components. I drilled it out a rubber stopper and it's moderately snug but there's not much more I can think to try aside from buying another microwave and crossing my fingers that one works.

Any idea how to make this work?

Lots of 304 eye screws, but google search is annoyingly inconsistent and does not filter despite using the minus shortcut. Any recommendations for manufactures would be greatly appreciated.

Hi

i'm to use some threaded rod like a lead screw - just normal M20 thread not trapezoidal - and want to have the lowest coefficient of friction between surfaces - probably choosing between zinc plated (not hot dip galv) and black oxide. it will be greased, moderate humidity climate and no weather exposure. but i cant find decent data.

can anyone advise or suggest between the two?

thanks!

Hello everyone,

I am asking if anyone out there has any idea where I can purchase more venturi pumps. We use them in our steel mill on a regular basis and the normal supplier we use (Fischer Scientific) has discontinued the product.

The product in question is: https://www.fishersci.com/shop/products/airejector-aspirator-pump/11474208?

I have found other "venturi pumps" but a lot of them are getting stupidly complicated for the application, and many of them are less robust than a fully metal piece (lots of them are plastic from what I see). The environment it would be in is greasy, hot, and full of abrasive dusts. I worry about the longevity of polyethylene parts compared to nickel plated brass.

I hopefully need a new supplier (so not just someone who has a couple left that they want to get rid of so they can discontinue the listing), but I will take any leads I can find right now.

I have searched Mcmaster-Carr, Schmalz, sciencekitstore (found 3 here, but that's all they have and will ever have), and Humboldt (I think they have parts that we could work with).

I want to ask if anyone out there has any idea where I can find these things in the U.S. I would have thought it shouldn't be hard considering every chem lab I was in through school had these on the sinks so that you can draw a vacuum for filtration, but apparently these things are becoming hard to find from what I am finding.

Picture of what I am talking about (this is from humboldt, I can't find a picture of the one from fischer scientific): https://prolabscientific.com/images/product/P-5565.jpg

Also, they are sometimes called air ejectors on these websites, not only venturi pumps

Thank you for any help you are able to provide!

Hi all. I am trying to design a fixture that essentially rocks a flat plane back and forth. I was going to do a lever type deal but the torque is like >50kFtLbs. I moved the fulcrum to the center and reduced torque a lot but now I want to use smaller pistons instead of a single double acting. I tried researching online to find info about common design practices for having this setup but I can't find anything. Basically, I'd need to set it up such that one is pushing while the other is pulling and vise versa. I know you can hook up opposing ports but I don't know much about parts selection and such. Anyway, I am just looking for any texts yall may have that I could reference to design the system. Thanks.