The chart above is from a Carrier heat pump, and it lists some common accessories. I have heard this common pressure switch (last on the list) called a low-pressure switch (because it opens on fall in pressure) and a high-pressure switch (because it's in the liquid line), but RARELY do I hear it called its […]

When evacuating, the FASTEST way is to use two large-diameter hoses connected to two core removal tools and the cores removed. These hoses are then connected to the pump using a tee or evacuation “tree.” However, when you only have one large hose, another acceptable method is to connect the large hose to the suction […]

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 […]