Lies, Damned Lies, and Manometer Readings

“It just knows.”

The senior HVAC technician I’d been working with on a home remodel answered with the conviction of decades of experience. I, on the other hand, was less certain. How could a new furnace “know” that it had just been connected to a 20-year-old air conditioner (from a competing brand), somehow read that unit’s cooling capacity, and then calibrate its own output to the precisely required airflow? In a bid to reconcile the reading on my manometer with the tech’s supposed savvy, I asked whether he was certain. He was, he told me, quite positive. “Tell you what,” he said. “If I’m wrong, then there’s probably 200 air conditioners in Princeton with bad airflow. And that can’t be right.”