Stacking Evaporator Coil Stages
In commercial HVAC you will find several different types of multi-stage evaporator coils, intertwined (like shown above), horizontal face split (one coil on top of another), and vertical (side by side).
Pay attention when staging a horizontal evaporator to ensure that stage #1 is on the bottom and stage #2 is on the top. If stage #1 is on top you risk condensate being pulled off of the coil when the water runs down the wet fins and then hits the dry second stage on the bottom.
By keeping stage #1 on the bottom the moisture adhesion will stay consistent as condensate drops no matter if one or both stages are calling.
You can also have this same effect when stage #1 fails and stage #2 keeps running on a stacked horizontal coil.
Bryan Orr is a lifelong learner, proud technician and advocate for the HVAC/R Trade