He hears a sound and
knows where
it hurts
A seventeen-year-old with no diploma, no license —
how he became a heating·cooling meister with 20 years' experience.
Our first meeting was on a villa rooftop in midsummer. The temperature was 36°C. He sat alone with the outdoor unit's panel disassembled, listening. There was no sound at all. The machine was off.
"What are you listening to?"
He didn't even take out his diagnostic gear. He knew from a single sound.
He left school at seventeen
He first held a tool at eighteen. When he was a high-school junior, his father collapsed. It was a stroke.
"I couldn't keep going to school. I had an older brother, but he had to work too, and I had to look after my younger siblings."
He got a job at a neighborhood heating·cooling company. There was only one reason.
That was 1989. Now it's 2025.
At first it was work I took to survive.
At some point I didn't notice,
this work became my reason to live.
He knows the language of machines
When 20 years pile up, the ear changes. He said he distinguishes the sounds an AC makes into 47 kinds. I asked if he was joking.
"Can all this be memorized?" I asked.
What he says about being an expert
"Isn't not having a license a complex for you?" I asked carefully.
He was silent longer than I expected. Then he spoke slowly.
- 01Machines don't lie. If there's a symptom, there's always a reason. I never wrap up until I find that reason.
- 02Fixing it isn't the end. It's only real if, after fixing, you explain to the customer why it broke. Being called back for the same reason is my failure.
- 03The field is the classroom. I couldn't finish high school, but I've been to 4,000 sites. What I learned there is more than any textbook.
- 04Accurate comes before fast. A job finished in 30 minutes that breaks again a month later is worse than one that took an hour.
We asked Partner Ko directly
Three years ago, he was dispatched to an elementary school
It was about an hour into the interview. I asked, "Is there a job that stays with you most?"
He lowered his head for a moment. Then he took out his wallet.
It was July three years ago. An urgent call came from an elementary school in Eunpyeong-gu, Seoul. Three ACs in the 6th-grade classrooms stopped at once. It was two days before final exams.
The temperature that day was 38°C.
The electrical load hit all at once, tripping the compressor protection circuits. All three had the same cause, but each needed a leak check, a wiring inspection, and a resetting of the sequential-startup circuit. He handled all three, one by one, alone. It took three and a half hours.
When cool air began to circulate in the classrooms again, the children waiting in the hallway came in.
The next day the school's admin office called. The homeroom teacher wanted to pass something along.
Inside the envelope was a small note.
It was the handwriting of a 6th-grader. Pressed firmly with a pencil.
"Thanks to you, sir, I took my exam in the cool. I'll study really hard. Thank you."
He put that note in his wallet. Three years later, it's still there.
I took my exam in the cool.
I'll study really hard.
Thank you ๐
"Why do you still have it?" I asked.
He slowly folded the note again and put it back in his wallet. Then he said,
I couldn't finish school,
but this child's exam was cool.
That's enough.
We asked a final question
As the interview neared its end, I asked one last thing.
He smiled. For the first time today, he smiled.
He'll be up on some rooftop today too.
With his ear turned to it.
A man who hears the sound a machine makes
and makes a home breathe again.
With one worn note in his wallet.
An expert like Partner Ko
is near you right now
4,200 jobs of experience · an expert who knows just by listening · completely free during beta
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