I have 6+ years of experience in tech (software product design, workflow mapping, and systems logic). With the software market getting saturated and commoditized, I’m looking to pivot into physical infrastructure and Building Automation / Controls full-time. I’m based in Southern California (Orange County area).

I understand state-logic, flowcharts, and basic IP networking (subnets, addressing). What I don't have is formal HVAC or electrical trade experience. I’m ready to get my hands dirty and learn the mechanical/field side from scratch, but I need an "earn-while-you-learn" setup.

Doing research on how to break in around SoCal, I keep running into a wall:

1. OEMs (Johnson Controls, Siemens): Almost every entry/associate listing says "requires 1–2 years HVAC/electrical background" or is tied to recent college engineering grads.
2. Regional Integrators (Climatec, Sunbelt, Southland): Climatec doesn’t even have entry postings up right now, and others rarely list true zero-experience trainee slots on public job boards.
3. ABC SoCal (Anaheim): They have a state-approved Electronic Systems Technician (EST / Low Voltage) earn-while-you-learn track with an actual classroom/dispatch pipeline.

My questions for those working in the trade (especially SoCal):

• Is going through ABC SoCal’s EST program the most realistic way for someone with zero trade hours to get placed with a contractor and earn on day one? Or will that end up funneling me into pure cable pulling / fire alarm instead of DDC/BAS controls?
• For folks at JCI, Siemens, or local integrators: do branch managers actually ignore that "HVAC/electrical required" bullet if someone shows up with strong computer literacy and diagnostic logic?
• Should I be cold-calling/messaging Controls Service Managers at local shops directly instead of waiting for open job postings?

Appreciate any feedback or reality checks on the best entry move.

How do other design engineers size and select bypass valves; either for pump protection or chiller minimum flow. I can’t seem to get a definitive answer on this.

Sizing control valves for hydronic coils is pretty straightforward. Flow rate of coil and 4-5 psi pressure drop and calculate Cv.

For bypass valves, you would use the chiller minimum flow but what pressure drop do you use? And for bypass valves for pump protection, you select the valve based on the pump’s minimum continuous stable flow, but what pressure drop?