Most modern vehicles use either an orifice tube or an expansion valve depending on your make and model. While you may have a personal preference of a blue orifice tube going on your truck rather than a yellow or brown one, the colors do matter. Orifice tube colors correspond to the orifice diameters of different makes and models of trucks. So when you need to replace this part, not just any color will do.
One of the benefits of having an orifice tube instead of an expansion valve is the minimal maintenance that these parts require. Since an expansion valve has moving parts, it can experience loss of proper metering or sticking open or closed after time.
An orifice tube does not have these issues, but it can become clogged with debris over time, at which time a replacement is necessary. Shop our online catalog or call today for top quality orifice tubes from Red Dot, a trusted brand with over 65 years of HVAC experience. With strategic distribution centers across the country, we can get you your Red Dot orifice tube where you need it and when you need it.
Create your account with us and get your new Red Dot orifice tubes today with our fast and easy shipping. Posted: September 23, Author: Becky Greiner.
What is an Orifice Tube? How an Orifice Tube Works To understand and appreciate the hard work of the orifice tube , we have to start with the AC evaporator.
When To Replace an Orifice Tube One of the benefits of having an orifice tube instead of an expansion valve is the minimal maintenance that these parts require. How to Flush : Remove Refrigerant. Dismantle AC system and remove components not being flushed. Dismantle the system components being flushed. Start flushing. Purge the system. Vacuum, leak test and recharge.
What is an Orphis? An orifice is an opening or a hole, most often in the body, such as your mouth or your nostril. We most often use orifice to describe a natural opening in our bodies, but it can an opening into any cavity, such as a hollowed out tree trunk, or the vent of a heating system.
How do you test an expansion valve? Use the manual to locate the thermostatic expansion valve. Lift the sensing bulb from the suction bulb well. Hold the sensing bulb in your hands for two minutes or place it in warm water. What are the symptoms of a bad evaporator core? How do you adjust an expansion valve? To adjust the static superheat, turn the valve's setting stem. Turning clockwise increases static superheat and effectively reduces refrigerant flow through the valve.
Turning counterclockwise reduces static superheat and increases refrigerant flow. The can gets cold and the longer you hold down the button the colder it gets. In a nutshell, that's how an orifice tube makes the air conditioning system cold. On the other side of the orifice the low pressure liquid flows into the evaporator core.
This looks like a mini radiator with aluminum fins. This device gets in the low 30 degree range. Ambient temperature air passes through the cabin air filter and through the cold aluminum evaporator fins. Then finally out into the interior cabin for people to enjoy. That's how an air conditioning system makes the inside of a car cold.
And we owe a great deal of thanks to the hard work of the orifice tube. As I mentioned this part fails due to other problems internally in the automotive air conditioning system. In a perfect world this part would never need servicing. But because of its construction it can become a blockage point and mess up the pressure balance of the system.
Since the hole in the brass tube is small the manufacturer had to protect it by placing screens around it. There are no other filters or screens in a factory installed automotive system. This means that any debris from damage to internal parts will collect around the orifice tube screens. When enough debris builds up the orifice will not meter the correct amount of Freon into the evaporator.
Therefore, a malfunctioning orifice tube is a sign of a larger internal problem occurring. Symptoms reported from the driver will often include an air conditioning system that cools when first turned on but quickly warms up as the vehicle continues operation. When a mechanic installs a manifold gauge set and takes pressure readings they will often find an automotive air conditioning system with unusual pressure readings. The readings might be consistent with a blockage or a defective compressor.
More specifically the low side will show below normal low pressure readings. An inexperienced mechanic just reading the low pressure side might think that the Freon level is low.
However, when you have a high side gauge connected and the tube is blocked you'll see higher than normal high side pressure readings. This means the system must be recovered and the part physically removed.
On General Motors vehicles the five inch long plastic and brass part is installed in the high pressure line after the condenser. There are little crimp marks on the aluminum pressure line that can help you find exactly where it's located.
On other vehicles they can be just about anywhere in the high pressure side. However, the component is usually not far away from the evaporator core on many models. The not so funny thing about removing this part is sometimes it's difficult.
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