Ever hear of a two- or three-ton central air conditioner? Does this mean a two-ton air conditioner weighs 4,000 pounds? Or is it a random term that tech folks use to impress us?
No, furnaces should not leak – but they do. Water and forced air furnaces just don’t mix. Furnaces in cold climates often have water flowing through humidifiers in the plenum. These humidifiers can leak. A modern high-efficiency furnace (over 90%) works by condensing steam from the products of combustion; this produces water that must be drained from the furnace.