Shop Unit Dripping Near Closing: Drain Pump Float Jammed

Water appearing beneath a ceiling unit toward the end of a long trading day, with nothing wrong through the morning or the early afternoon. The unit runs continuously from opening. Shorter days pass without incident.

Water appearing only after many hours of running describes a rate rather than a failure. Condensate is produced continuously while the unit cools, and the pump has to move it away at least as fast. Where the pump has lost some of its speed, it keeps up while the tray still has spare depth and falls behind once the day is long enough to use that depth up. The useful observation is when it fails, not that it does.

A condensate pump is asked to remove water at the rate the coil produces it, and the spare depth in the tray is the only reserve. Deposit around the float slows how quickly the pump is called, so each cycle starts a little later and removes a little less. On a short day that reserve absorbs the difference. On a long one it does not, and the tray reaches its edge at roughly the same hour every time.

The float and chamber are cleaned so the pump is called promptly again, restoring the margin rather than adding capacity. The general point is about how a marginal system reports itself: it does not fail randomly, it fails at the end of demand. Anyone told a drainage fault is intermittent is worth asking when, because the answer is usually a duty pattern rather than a mystery.