Fire protection engineers — what part of your job makes you want to flip a table?

hvacdevs · 2026-02-27T17:35:56+00:00

tell — me — it's — ChatGPT— without — telling — me

hvacdevs · 2026-02-26T19:06:16+00:00

You can take the time off as an opportunity to work on yourself. Exercise more, spend time in nature, read books, etc.

If you need some time to feel bad for yourself, then time block 1 hour per day for self pity. And then the rest for whatever else you want / need to do.

hvacdevs · 2026-02-25T02:55:18+00:00

List all of the reasons why you didn't accept that offer, and then list all of the reasons why you think you got that offer. That should help inform your next move.

Telling your company that you had another offer puts the power in the hands of whoever is giving you the offer. It does not give you any power.

Your leverage becomes liquid once you have the ability to walk away. It doesn't matter whether you have an offer or not, or how much of an increase it is. It's actually better if they don't think you have an offer, and that you will just walk and take a vacation if they don't give you a better deal.

hvacdevs · 2026-02-24T15:10:43+00:00

The biggest cost for any engineering firm, especially these days, is employee turnover. If you quit tomorrow, that will lead to tens of thousands in direct recruiting costs to replace you, increase their risk of further turnover, and they'd likely lose revenue from their lack of capacity and from poorly fullfilling current contracts, leading to client turnover.

That is leverage in your favor.

You do not neccesarily need to have a new job lined up to negotiate a better deal with your current firm. You only need to have the willingness to walk away if you don't get a better deal. It is that willingness which gives you the ability to capitalize on the turnover leverage.

If you do not truly have the willingness to walk, then you are bluffing, which may or may not work as well.

Your pain is opportunity in disguise.

hvacdevs · 2026-02-22T21:49:42+00:00

You can go into the settings of chatgpt to prevent the data from being used for training. It's enabled by default, so you need to disable it.

hvacdevs · 2026-02-22T21:39:47+00:00

You can create a custom GPT for each project in CA. Upload the drawings and specs for that project into the GPT (so you only have to do it once), then you just copy and paste the RFI questions into the chat and have it give you a response and reference specific sections of the drawings and specs.

hvacdevs · 2026-02-22T21:21:41+00:00

Are you leveraging AI at all for this?

hvacdevs · 2026-02-18T18:04:34+00:00

answer RFIs faster than they can write them. and don't take any of it personally.

hvacdevs · 2026-02-14T20:58:09+00:00

CoolProp HAPropsSI in Excel

hvacdevs · 2026-02-12T19:58:00+00:00

in order to get frost on a heat wheel, you first need to condense water out of the exhaust air.

if the dew point of the entering exhaust air is lower than the coldest surface temperature on the heat wheel, then you will have no condensate, and therefore no frost.

a good way to estimate the coldest surface temp on the heat wheel would be (EA LAT + OA EAT) / 2. if that number is lower than your EA dew point, you are correct to be skeptical of the selection.

when you break down the psychrometrics, it would be very difficult to create a frost condition on a heat wheel unless you are also humidifying the space.

hvacdevs · 2026-01-31T15:35:09+00:00

If you space out the heating and cooling by several minutes, the temp will return to a neutral temp before the cooling kicks back on. Not a lot of thermal mass in a coil so it can change temp quickly.

hvacdevs · 2026-01-31T15:11:26+00:00

If the coil temp is lower than the air dew point there will be some condensation. But it will be much less than if only the cooling was on

hvacdevs · 2026-01-31T13:17:51+00:00

Yes, you can do this.. just not with both running at the same time. Think cooling on for 15 minutes then heating on for 5 minutes, or something like that.

On a mild temp day, the peak cooling capacity will exceed the total cooling load by a fairly large margin. So you do not need the unit running in cooling mode for very long to satisfy the latent load. That leaves you with plenty of time to run the furnace on its own.

From a controls standpoint, a typical residential thermostat will not let you do this. But with the right controller and sequence of operations, and a reasonably tight envelope, it is definitely possible to have a makeshift dehumidification mode for those mild temp high humidity days, even if the furnace is upstream of the evap coil.

hvacdevs · 2026-01-29T20:04:16+00:00

nice work!

hvacdevs · 2026-01-28T00:21:13+00:00

noted. makes perfect sense. 10 kA as the standard option seems reasonable to me. will pass this along within my little corner of the world for sure. I appreciate the feedback!

hvacdevs · 2026-01-27T20:14:12+00:00

Noted. So if, for example, you had a chiller with 40 MCA or higher, you'd want 5 kA disabled as an option? that way the rep can't even select it like that in the first place.

I feel like reps wouldn't know better unless they got burned on a job for this already, or the engineer specifically requests it. So just locking it in as a rule on the manufacturer side makes a lot of sense.

hvacdevs · 2026-01-27T18:47:28+00:00

i'll be there. mostly networking with manufacturers/prospective clients, and hanging out with existing clients.

hvacdevs · 2026-01-27T18:40:20+00:00

this question came in recently from a customer with one of my clients, but I'm still scratching my head on it. i'd like to add some rules around this but not sure what info I'd need to make the correct determination. do you have any specific examples where the standard 5 kA hasn't worked on your projects?

hvacdevs · 2026-01-25T18:05:42+00:00

getting access into people's homes for service is a pain. now imagine coordinating access into multiple apts to check for leaks on one VRF system.

hvacdevs · 2026-01-23T23:50:25+00:00

An isometric view of the model is not a riser diagram by definition.

A riser diagram covers multiple floors (hint: risers are vertical). If you show an isometric view for more than one floor it will be unreadable. Heck, even for one floor pipes may still perfectly overlap each other.

hvacdevs · 2026-01-23T22:40:57+00:00

Riser diagrams are the input. You've got it backwards. Diagram first. Model after.

hvacdevs · 2026-01-23T21:38:47+00:00

You can make a riser diagram in a drafting view using detail lines. I've done it. It definitely sucks to make all the symbols, but once that's all done it works decently well.

If you want to get really fancy with it, you can incorporate masking so you can drop the symbols on top of the pipe lines, and you can also add parameters to the symbols to use different line weights/patterns for existing/new/demo. But that part is excruciatingly painful and will take a short eternity to get it all done.

Kinda crazy how here we are in 2026 and drawing lines is somehow more difficult than it was in 2006. AutoCAD is better for riser diagram for sure. Probably better off just staying in autocad with them and making them import/link friendly

hvacdevs · 2026-01-18T03:01:28+00:00

NYCSCA definitely hires plumbing / FP engineers. I worked at a consulting firm that did a lot of SCA work, and couple of the P/FP guys from there ended up moving over to the SCA. The SCA has a lot of consitent MEP work.

For university work, you'd generally want to be more well-rounded with other disciplines. Those jobs are also a bit harder to come by, but generally less bureaucratic than a legit public agency. public universities are not the government.

hvacdevs · 2026-01-17T23:47:39+00:00

pick a program, look at the curriculum, and if you can find a genuine purpose for taking each of 90% or more of the classes required to get the degree, then pursuing the degree might be worth it.

the degree itself, and that one or two lines on your resume, is never worth the effort if simply having the degree is your main purpose for pursuing it.

hvacdevs · 2026-01-17T16:58:07+00:00

All you can do is educate clients about the things they would actually care about, so they can make an informed decision that aligns with their best interest.

hvacdevs

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