Leaking Air Handler – Air Leaks
Leaking Air Handler- Air Leaks - Dear Richard… my partner and I moved into a brand new mill conversion/rehab condo last year that we absolutely love, but after the summer was over, I went into the utility closet (where the air handler/gas furnace are) and noticed that there was copper corrosion crust/rust that had run down from the air handler (not sure from where, but somewhere fairly high up on the AHU). It had dried up, and didn’t seem to be enough to run down the sides of the burner even–no streaks). (more…)
Air Handlers - An air handler is usually located in the garage, a closet, or in the attic (unless you have a package unit then the air handler is incorporated into one system). It is essential to any AC unit and heating forced air system. All AC units need an air handler or way to move air. It can be a part of your furnace and houses the 
This is an air conditioner condensation drainpipe that drains the condensation from the evaporator coil. The evaporator coil operates below the dew point when the system is in air conditioning mode. As humid air passes over the cold evaporator coil the humidity or moisture in the air condenses. The condensation runs down the coil and into a condensation drain pan. 
York VAV Air Handlers | HVAC Zoning - This York air handling unit serves several VAV boxes and runs on a static pressure control set point determined by a 
Air Handler Blower Motor - All air handling units have a blower located inside the air handler cabinet. The air handler blower motor has a motor that drives it. Some air handling unit blowers are direct drive and some are belt driven.
York Air Handling Unit Chilled Water Coil - This coil is a cooling coil in a large commercial York air handling unit. The air handler serves approximately 80 VAV boxes and is responsible for providing cool conditioned air to all the zones the VAV boxes serve based on a set point determined in a DDC program and the chilled water coil seen here. 
This photo shows the air handler blower compartment. This is how the air handler is opened when the blower needs service or repair. The evaporator coil is on top of the blower which makes this an upflow air handling unit. The supply air ductwork will be above the AHU. Since this air handler is installed in a closet then the ductwork is installed in the ceiling and makes this an ideal installation for AC since cool air falls. 
This is a horizontal flow air handler installed in the attic. Notice the drain pan under the air handling unit to catch condensation if the primary pan were to overflow. This is the secondary condensation pan which is installed under the air handler to save a ceiling.