There was a story that came out recently based on an ASHRAE study performed by David Yuill from the University of Nebraska. The study appeared to indicate that condenser coil cleanliness makes no difference on system performance and efficiency. Those of us who have worked in the field know that coil cleaning matters because most […]

Disconnects walk the fine line of being HVAC or electrical, but the HVAC technician is allowed to repair and replace disconnects in most places. Even if you work at a place where it isn't allowed, finding problems is a diagnostic skill you will want to have. As always, work safely with proper safety gear and […]

Relays can be used for many different control applications, including controlling fans, blowers, other relays, or contactors, valves, dampers, pumps, and much more. A 90-340 is a very common, versatile relay that many techs have on their truck. So, we will use it as an example. A relay is just a remotely controlled switch that […]