The Mechanical Room

Real commercial HVAC knowledge. No fluff.

Chillers, boilers, cogen, controls, hydronics — from a Local 30 Operating Engineer working in NYC.

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Why Is My Chiller Plant Running All Chillers on a Mild Day? Low Delta-T Explained

Why Is My Chiller Plant Running All Chillers on a Mild Day? Low Delta-T Explained

Your chiller plant is running more chillers than it should for the load. Nine times out of ten, it's low delta-T. This covers how to find it, what causes it, and how to fix it.

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Plate Heat Exchanger Not Performing? How to Diagnose Fouling, Leaks, and High Approach Temps

Plate Heat Exchanger Not Performing? How to Diagnose Fouling, Leaks, and High Approach Temps

Plate heat exchangers are everywhere in commercial HVAC, and when they go bad, they go bad fast. This covers how to read the signs and what to check before it becomes an emergency.

What Is Static Pressure in Commercial HVAC? A Field Tech's Guide to Measuring It Right

What Is Static Pressure in Commercial HVAC? A Field Tech's Guide to Measuring It Right

Static pressure comes up constantly in commercial air handling, but a lot of techs learn just enough to get by. This covers what it actually means, how to measure it correctly, and how it connects to everything else in the system.

How to Read Chiller Approach Temperatures (And Why They're the Most Important Number in Your Plant)

How to Read Chiller Approach Temperatures (And Why They're the Most Important Number in Your Plant)

If you're not trending approach temperatures on your chillers, you're flying blind. This is the single most important metric in your plant — and most guys aren't even looking at it.

Boiler Water Treatment 101: The $8,000/Year Program That Saves You $65,000 in Repairs

Boiler Water Treatment 101: The $8,000/Year Program That Saves You $65,000 in Repairs

A boiler with proper water treatment lasts 30 years. Without it, you'll be lucky to get 10. This covers what every operating engineer needs to know about keeping your water right.

Cogeneration Plant Operations: A Local 30 Engineer's Real-World Guide to Running CHP

Kyle Pozen · Feb 2026
Cogeneration Plant Operations: A Local 30 Engineer's Real-World Guide to Running CHP

Why Your Building Automation System Isn't Working: Overrides, Bad Sensors, and How to Fix It

Kyle Pozen · Mar 2026
Why Your Building Automation System Isn't Working: Overrides, Bad Sensors, and How to Fix It

Is VRF Worth It for Commercial Buildings? An Honest Breakdown of Pros, Cons, and Hidden Costs

Kyle Pozen · Mar 2026
Is VRF Worth It for Commercial Buildings? An Honest Breakdown of Pros, Cons, and Hidden Costs

Condensing Boiler Not Condensing? Why Your 95% Efficient Boiler Is Running at 85%

Kyle Pozen · Mar 2026
Condensing Boiler Not Condensing? Why Your 95% Efficient Boiler Is Running at 85%

Why We Use Computrols for Building Automation

Kyle Pozen · Mar 2026
Why We Use Computrols for Building Automation
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Field Scenarios & Quizzes

Field Scenarios

The same way I'd quiz a new tech on the job. Every question has an explanation.

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On-The-Job Training Modules

Structured deep-dives into specific commercial HVAC systems. Move beyond basic troubleshooting and learn how to actually commission and optimize plant equipment from the ground up.

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Browse by Topic
Hydronics
Chilled water, hot water, steam, pumps, and piping systems
Airside
RTUs, AHUs, VAVs, and air distribution systems
Controls & BMS
Building automation, DDC, BACnet, and control sequences
Plant Systems
Chillers, boilers, cogen, cooling towers, and central plants
Diagnostics & Troubleshooting
Systematic approaches to finding and fixing problems
PM & Reliability
Preventive maintenance, water treatment, and equipment longevity
VRF / DX Systems
Variable refrigerant flow and direct expansion systems
Kyle Pozen

About Kyle Pozen

My grandfather started his own shop in Manhattan. My dad followed him into the trade, and I followed my dad. 20 years later, I now run my own business called C&S Service and Controls and get to work with some awesome people, including my best friend and my brother. Commercial HVAC, BMS, and controls across NYC.

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