Why Defrost? Let's start with the basics and move on from there. Defrost is necessary when the coil temperature drops below 32°F. Defrost can be as simple as turning the compressor off for a period of time or as elaborate as reversing the flow of refrigerant for the whole system or just parts of the […]

Proper sizing and orientation of grilles, registers, and diffusers may seem like such a simple thing, but it's an area where confusion and mistakes are commonly made. First, let's define some terms. Return  A return draws air into a return duct system with negative pressure compared to the space, usually via a fixed “grille” (also […]

In commercial HVAC, you will find several different types of multi-stage evaporator coils: intertwined (shown above), horizontal face split (one coil on top of another), and vertical (side by side). When staging a horizontal evaporator, pay attention to ensure that stage #1 is on the bottom and stage #2 is on the top. If stage […]