#condenser

Tech Tips:

This is a basic overview of the refrigeration circuit and how it works. It isn't a COMPLETE description by any means, but it is designed to assist a new technician or HVAC/R apprentice in understanding the fundamentals. First, let's address some areas of possible confusion: 1. The word “condenser” can mean two different things. Many […]

Condenser Fan Blade Placement

In a previous article, I talked about wiring permanent split capacitor (PSC) condenser fan motors. While researching the topic, I realized that there isn’t as much information available on condenser motors as there is on their counterpart—the indoor blower motor. I had never really given it much thought, as I assumed that the condenser motor […]

Universal Condenser Fan Wiring Options

Assessing the Situation It is fairly common for a service technician to come across a failed condenser fan motor in the field. It doesn’t matter if we are talking about really old or fairly new equipment—condenser fan motors sometimes fail. The issue is deciding whether to use an OEM (Original Equipment Manufacturer) or a universal […]

How to Replace a Condensing Fan Motor

Service calls about condensing fan motor failure are quite common. Even though fan motor replacement is a standard procedure for residential split systems, it requires careful attention to safety and detail. This article will give you a step-by-step guide to replacing condensing fan motors. Along the way, we will also explain a few best practices […]

Condensing Temperature, Condenser Split, and Subcool

In this podcast, Bryan talks about condensing temperature, condenser split, and subcooling. All three of the values are proportional. If one changes, all three of them will change. Saturation is also a critical concept that relates to all three of those, so we also cover those relationships. As you remember, a condenser rejects heat and […]

The Basic Refrigeration Circuit

In this episode of HVAC School, we discuss the entire basic refrigerant/compression refrigeration circuit. We are in the business of moving heat. Heat refers to motion in the molecules. Temperature is the average velocity of those molecules. Heat needs a temperature differential to move. So, HVAC systems absorb heat when the refrigerant is colder than […]

Heat Pump Refrigeration Cycle

How to Evacuate an AC system, Full Vacuum Procedure

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In this short podcast episode, Bryan talks about crankcase heaters, including their different types, what they do, and when we need to use them.

Crankcase heaters usually come in belly band varieties, but some can be inserted into the sump of the compressor. As their name suggests, crankcase heaters heat the crankcase when the compressor is off. They prevent flooded starts since the heat keeps refrigerant from condensing to a liquid in the compressor when the system isn’t running.

Long off times, long line sets, and cold temperatures all increase a system’s risk of flooded starts. Hard shutoff TXVs, liquid line solenoid valves, and crankcase heaters are all ways to reduce these risks; the valves hold liquid refrigerant back, and crankcase heaters merely prevent refrigerant from condensing.

Crankcase heaters have to be wired to the line side of the contactor or starter. They’re often wired around one of the contacts (with a single-pole contactor). When the contact opens, there is a circuit from one leg, through the crankcase heater and compressor windings, to the other leg. This method does NOT use the compressor winding itself as a crankcase heater. When you use a crankcase heater on a compressor with a seam, you want the part of the heater that does the tensioning near the seam. Crankcase heaters should be installed at the base of the compressor, and you’ll usually use OEM crankcase heaters.

“Crankcase Heaters and Single-Pole Contactors” tech tip: https://www.hvacrschool.com/crankcase-heaters-and-single-pole-contactors/

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