During the past several years, new-style silicon nitride igniters for furnaces and boilers have taken over the industry. Virtually all new residential gas furnaces now feature the new technology.

Measuring the electrical resistance (ohms) of motors, compressors, and other electrical devices in HVAC systems may seem straightforward. But when the measurements of zero (0) or “OL” (overload) come up in discussions, it becomes clear that there is quite a bit of confusion around this topic.