Tech Tips

Belly band crankcase heater When I first started in the trade as an apprentice, we worked on many Trane heat pumps that used crankcase heaters. These crankcase heaters slid into the compressor sump on the big orange Tyler reciprocating compressors. They looked like the one in the picture below. It was very common for these […]

Microchannel is a coil type used in many evaporator and condenser coils. You can easily identify it by its flat tubes, and its fins look like waves between the tubes. The technology was developed for use in the automotive industry and is used for radiators and automotive A/C condenser coils. These coils are made of […]

We've all heard some version of the phrase “heat rises,” but is that really true? First, we need to remember that heat is energy, not matter. Heat is a force, not a thing. So, while heat may result in changes to matter (stuff), it isn't matter itself. When we add heat to stuff, the molecules […]

A refrigerant is anything we use to move heat from one place to another using the compression refrigeration circuit. However, the history of refrigerants and the different kinds is quite diverse and interesting. Have you ever noticed how your skin feels cool after you apply some rubbing alcohol to it? For a long time, scientists […]

Sometimes, we can focus on the more complicated aspects of a system and parts installation—like evacuation and flowing nitrogen—and forget the simple and critical common-sense steps to keep contaminants out of the system. One of these is pre-cleaning the tubing and connection before cutting or unsweating. For example: If you are replacing a coil, use […]

The photo above is of a real condenser coil we cleaned. The outer fins looked OK, but dirt and lint were packed deep inside. We also had sky-high head pressure and condensing temperature; those are telltale signs of an impacted condenser. That situation illustrates that a coil can sometimes look OK at first glance but […]

We've all been new at one time or another. So, there is no need to get all judgy about some of the mistakes new techs make just because they are inexperienced. However… These are some very preventable mistakes that occur due to simple oversights and carelessness that need to happen 0% of the time. 1. […]

To answer the question in the title, we use it as a measurement of pressure. REALLY, it is a measurement of distance. First, any scale CAN be used to measure vacuum (negative pressure) and positive pressure. The trick is knowing which is best suited for which and the size of the scale. Larger units of […]

The piston (fixed orifice) and TXV (thermostatic expansion valve) are the two most common metering devices in use today, though some modern systems utilize an electronically-controlled metering device called an EEV (electronic expansion valve). It should be noted that there are other types of fixed-orifice metering devices, like capillary tubes; however, their use is not […]