The most common method to defrost appropriately in refrigeration involves both time for initiation and a combination of time and temperature for defrost termination (ending defrost). But why can't we just use temperature or time alone? (You may wonder.) Imagine a common freezer with a designed box temperature of -10°F and a coil temperature of […]

Every now and then, a tech will call me and give me the same story of woe. They're working on a system and have the following readings: Low superheat Low suction pressure Low head pressure They'll reassure me that the system airflow is correct. So, what could possibly be wrong? I'll ask how they could […]

Full disclosure: as a technician, I was guilty of setting the fan to “on” at the thermostat for many years. I never really thought of any of the negative impacts that could happen. I wanted to circulate the air and keep air moving through the high-efficiency air filter that most of our houses had. Later, I […]