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Discover the 5 Main Types of HVAC Fittings

Variety of fittings on a wooden table - types of HVAC fittings

Anyone who’s worked on HVAC systems knows they’re not as simple as they appear at first glance. Among having to navigate the labyrinth of ductwork, layouts, designs and their subsequent pros and cons, there are a variety of variables that can negatively impact the system’s efficiency and performance if the right connections aren’t made at critical conjunction points. 

Technicians must possess a firm understanding of the ins and outs of the different types of HVAC fittings, the materials they're made out of and what situations call for one type over the other. Parts Town will help chart your shortcut through the confusing world of HVAC, outlining the characteristics of each type of fitting and when you might use them. 

What Is a Fitting in HVAC?

Fittings are designed to attach and secure piping and ductwork in HVAC. They are especially important in maintaining the structural integrity and energy efficiency of the heating, cooling and ventilation systems. Each type of HVAC fitting is designed to rectify a specific design flaw, fill a gap in engineering or simplify installation and repairs. Let’s check out the different types of HVAC fittings and their functions, pros and cons below!

Types of HVAC Fittings

Deciding which type of fitting to use can quickly become overwhelming when considering the sheer number of categories and subcategories and their overlapping applications. In this guide, we’ll learn why some are used in favor of others based on the location, accessibility, material of piping or ductwork, space restrictions, building codes, etc. This isn’t an exhaustive list, but we’ll cover some common types of HVAC fittings you’ll find when installing, repairing and maintaining your unit.

Union Fittings 

Union femal fitting on white background - types of HVAC fittings

Union fittings are especially nifty in applications that need to be easily accessed for frequent maintenance and repairs, such as busting a stubborn clog while cleaning an AC drain line. For that reason, you’ll often find them in high-pressure situations, like valves, pumps, sight glasses, filters, etc. Unlike a coupling, union fittings don’t need to be cut to access the system. Instead, all you have to do is unscrew the collar, making them ideal for service.

Reducer Fittings 

Galvanized steel reducer T - 5 main types of HVAC fittings 1

Reducer fittings are used to connect ductwork or piping that are of incompatible diameters. In other words, we want to attach a bigger pipe to a smaller one without restricting airflow or creating too much turbulence. Since sizing in HVAC can vary widely based on design and space constraints, reducer fittings help fill the gaps without compromising system pressure, ensuring airflow remains steady and the HVAC unit is efficient. There are two main types of reducer fittings:

  • Concentric reducers – In layman's terms, concentric is just a fancy way of saying that it is conically symmetrical. In this context, concentric reducers look a little bit like a funnel, where the wider end gradually tapers in on a symmetrical, well-balanced axis. They are typically found in vertical installations. 
  • Eccentric reducers – Less common of the two, eccentric reducers, on the other hand, are not symmetrical, favoring one straight edge side that offsets a tapered side. These types of HVAC reducers are typically seen in horizontal installations. 

Press Fittings

Tool for press fitting - 5 main types of hvac fittings

Press fittings are used when the need for convenience is high. They work by sealing the fitting around a pipe with the pressure exerted by an electric press tool. They can quickly connect and disconnect sections of piping with ease instead of relying on welding, soldering and brazing to complete the same task. As you can imagine, this saves countless time and money on the job, making them a modern alternative to old-school laborious techniques.

Tee Fittings 

Brass adapter tee fitting - 5 main types of HVAC fittings

Another type of HVAC fitting is tee fittings, which get their name because they are shaped like the letter “T.” These fittings are used in situations where pipes or ductwork must branch off in different directions, allowing air or fluid to travel to separate rooms or areas within the HVAC system. Let’s go into a little more detail about the different types of tee fittings used in HVAC and where you might use them:

  • Standard tee – The standard tee is the most common type of tee fitting used in HVAC. It uses straight lines to create that signature “T” shape. These are used when connecting two points that are evenly matched in size. 
  • Reducing tee – Reducing tees work in much the same premise as reducers fittings, but the branch tapers in to connect to a smaller outlet. You’ll find these in applications with pressure differences, such as zoned HVAC systems or retrofitting.
  • Bullhead tee – On the other hand, bullhead tees are leveraged in systems where the branch is larger than the run connections. Bullhead tees can be used in place of reducers when less flow needs to run in two different directions.
  • Wye tee – Wye tees angle off at a 45 or 60-degree angle rather than the 90 degrees found in other types of tees. These fittings are chosen to reduce turbulence and resistance or when space constraints prevent the use of standard tees.

Flare Fittings 

Copper pipe flare fitting - 5 main types of HVAC fittings

A flare fitting is another type of HVAC fitting typically seen connecting refrigerant lines where thermal expansion and contraction, high pressure and vibration are present. The design incorporates one end that’s flared at a 45-degree angle. The flared end is attached to the tubing with a flared nut and sleeve and secured to create an airtight seal. Not only does this provide a reliable seal, but its convenient design makes it easy to dismantle and reassemble for easy access for maintenance and repairs. 

Please contact a local authorized service agent who can help with this specific unit and all your heating and cooling needs.