If you live in a dry climate, a humidistat is pretty straightforward; it just turns a humidifier on and off. That's about as simple as it gets. If you are in a humid climate, some people have taken to wiring in humidistats as dehumidistats to help control humidity when they are away. The first thing […]

Proving flame is an important part of the gas firing sequence. Without proof of flame, you risk dumping unspent gas into the heat exchanger, resulting in an explosion. There are many ways to “prove flame,” but we are focusing on the flame sensing rod (flame rectification) method here. Here are the facts: Flame sensing rods, […]

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 […]