If you work in large commercial offices or mixed-use buildings, you almost certainly work with VAV systems regularly. If you aren't familiar with VAV, this is a quick intro to the basics so that they won't seem so overwhelming. VAV stands for variable air volume; this means that the AHU (air handling unit) can vary […]

Airflow, airflow, airflow… When we set up and commission comfort cooling and heating systems, we need to pay more attention to airflow before worrying about the fancy controls or the refrigerant circuit. So, as a thought exercise, let's consider a typical 2-ton, straight cool, TXV residential system and think through what happens when we alter […]

Does setting a thermostat too low cause an air conditioning system set in cool mode to freeze? The answer is no, at least not directly. However, low evaporator load (low return temperature or low airflow) and low outdoor ambient temperature can lead to evaporator coil freezing. Low indoor setpoint can lead to low return air […]