Service Install / MEP learning library

Understand the system before you touch the system.

Free, interactive MEP lessons across mechanical, electrical, and plumbing systems for technicians, apprentices, shop owners, and anyone who wants to understand the work behind reliable service.

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A free starting point

Practical, visual, no login required.

Use the demos to build intuition, then take the questions back to the truck, the classroom, or the shop floor.

Machines

See compression, expansion, and heat movement instead of memorizing a diagram.

Power

Build intuition for frequency, voltage, motors, and the measurements technicians trust.

Diagnostics

Practice the concepts that turn a symptom into a safe next move.

Field craft

Short visual lessons for installs, service conversations, and the work around the work.

Interactive lessons

Start with the moving parts.

Pause, change a variable, and see why the system responds. These are teaching tools, not black boxes.

01 / Machines

How a scroll compressor moves refrigerant

Watch the orbiting scrolls create suction, compression, and discharge in one continuous motion.

Two spirals nested together. One stays still, the other orbits — squeezing gas from the outside in.

Cool suction vaporCompressingHot discharge vapor

Suction (outer edge)

Vapor is drawn into the outer pockets

Cool low-pressure suction vapor enters at the outer edge of the scroll set. As the orbiting scroll moves, it seals off crescent-shaped gas pockets against the fixed scroll. Nothing is squeezed yet — the gas is simply trapped, ready to be carried inward.

Gas's journey

Why techs like scrolls

• Far fewer moving parts than a reciprocating compressor — only one orbiting part.
• Smooth, near-continuous flow means quieter operation and less vibration.
• Tolerant of small amounts of liquid and very efficient at part load.

Simplified for training. Real scrolls use precisely machined involute profiles and tip seals; never operate one backwards (reverse rotation) as it will not pump and can be damaged.

02 / Diagnostics

The refrigeration cycle, component by component

Follow the state change through compressor, condenser, metering device, and evaporator.

Tap a component to learn its job. Color shows the refrigerant state.

Hot high-pressure vaporHigh-pressure liquidCold low-pressure mixCool suction vapor

Compressor

Raises pressure & moves refrigerant

Low-pressure vapor in → hot high-pressure vapor out

The pump of the system. It draws in low-pressure cool vapor from the suction line and compresses it into a hot, high-pressure vapor, pushing it toward the condenser. This is what circulates refrigerant around the loop.

Cycle order

Simplified for training. Real systems add accessories (receivers, accumulators, driers) and the four core processes — compression, condensation, expansion, and evaporation — always repeat in this order.

03 / Power

Three-phase power you can see

Change frequency and watch the waveform and motor response move together.

It's all about frequency

Frequency just means: how many times the electricity wiggles back and forth every second. We measure it in hertz (Hz). 60 Hz = 60 wiggles a second!

Try:

Frequency60 Hz

Slow (5 Hz)Fast (90 Hz)

Motor speedFaster wiggle = faster spin. This 4-pole motor turns about 1,800 RPM at 60 Hz.Region for 60 Hz: USA, Canada, much of the Americas

Think of clapping

Frequency = how fast something repeats

Clap your hands slowly — that's low frequency. Clap super fast — that's high frequency! Electricity does the same thing: it pushes one way, then the other, over and over. Each full push-and-pull is one cycle, and the number of cycles per second is the frequency.

50 Hz vs 60 Hz

Two speeds the world runs on

Long ago, different countries picked different speeds and never changed. The USA and most of the Americas use 60 Hz. Europe, most of Asia, Africa and Australia use 50 Hz. Same electricity — it just wiggles a little faster or slower. Because motor speed follows frequency, a fan built for 60 Hz spins a bit slower on 50 Hz.

60 Hz motor

≈ 1,800 RPM

50 Hz motor

≈ 1,500 RPM

What is a VFD?

Variable Frequency Drive — a speed knob for motors

A VFD is like a gas pedal for a motor. Normal power is stuck at one speed (50 or 60 Hz). A VFD takes that power and changes the frequencyto whatever it wants — so it can make the motor go slow, medium, or fast. Slide the frequency above and watch the fan change speed: that's exactly what a VFD does!

Saves energy: slowing a fan or pump a little saves a LOT of electricity.

Gentle start: the motor eases up to speed instead of slamming on, so parts last longer.

Just-right comfort: a chiller can run slow on a mild day and fast on a hot one.

Simplified for training. Real RPM is slightly below synchronous speed (slip), and VFDs also adjust voltage with frequency. Always follow manufacturer specs and lockout/tagout.

Pick a path

What are you curious about?

Start with a story, try a lesson, and follow the next question. Nothing is graded and you can always try again.

Try a check-in

Teach it back

One quick question. Your answer stays in this session and is never used as a certificate score.

What does a refrigeration system move?

The growing library

More ways to get sharper.

Short lessons for the concepts that show up in the field, in the classroom, and in the office.

machines

Refrigeration cycle

Compressor, condenser, metering device, evaporator

machines

Scroll compressor

Orbiting scrolls, suction, compression, discharge

power

Three-phase power

Frequency, waveform, and what a VFD changes

diagnostics

Superheat and subcooling

Two measurements that tell a richer story

diagnostics

Psychrometrics

Temperature, moisture, and comfort in one picture

field craft

Electrical safety

Meters, capacitors, switching devices, and fundamentals

For shop owners

Free learning earns attention. Better workflows earn trust.

Service Install connects the calls, texts, web inquiries, and field work that learning eventually has to support.

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