The System That Ran Constantly and Never Hit Temperature

"Topped off refrigerant" is not a diagnosis.

It's a treatment. Sometimes the right one — systems can lose a small amount of refrigerant over many years and a charge gets them back where they need to be. But refrigerant doesn't evaporate. If a system is consistently low, something is leaking. Topping it off and leaving is the HVAC equivalent of adding oil to an engine that's burning it and telling the owner the car is fine.

She'd been through it once the summer before. AC couldn't keep up on hot days — set the thermostat to 74, house sat at 80, system ran from morning until late evening. Company came out, found it low on refrigerant, charged it, charged her for it. The system ran better for a few weeks. Same problem returned.

Her bill from that call was the one she showed us. Another refrigerant charge. The next call would have been another one.

She called us skeptical. Said the word "skeptical" on the phone, which we respected — at least she knew what she was coming into.

The refrigerant was part of it. There was a small leak, and we found it — not on the first pass, but on a thorough search with electronic detection. But the refrigerant alone didn't explain the scale of the problem. A system a little low on refrigerant loses efficiency. A system losing 30% of its conditioned air before it reaches the rooms isn't a refrigerant problem.

We inspected the duct system. The crawl had four sections with compromised connections — two fully separated, two with collars that had pulled loose at the trunk and were venting into the crawl space below the floor. The system was conditioning air, and then about a third of it was disappearing into the ground before it reached a single register. That's why refrigerant charges helped briefly: a freshly charged, efficient system can almost overcome a 30% duct loss on a mild day. But when the temperature climbed, it couldn't.

We sealed the duct connections — mastic compound and proper tape on every joint we touched. We also fixed the refrigerant leak, replaced the service valve that was the source, evacuated, and recharged correctly.

The house hit temperature. First time that summer.

She called two weeks later to say it had been 97 outside and the house was sitting at 73 without the system running constantly. We told her that was what correctly working felt like.

That was the whole diagnosis. Find out where the air is actually going.