How do you connect a flexible duct to a rigid duct?
Quote from the video:
Quote from Youtube video: So what you're going to do then you're going to set the duct down grab a zip tie. You're going to feed it through up. And under the jacket. So it's up against.
What happens if you oversize duct?
The Ducts Are Too Large
Eventually water will fill the hose entirely and start flowing out the other end, but the flow will be weak. Even then, it can take an hour or more for the hose to fill up entirely to the point where water will eventually be forced out.
How do you size a flexible duct?
Measure the length and width of the room where the flex duct will be supplying the air. Multiply the length and width together to get the square footage of the room. For example, a 10-by-10 room will be 100 square feet.
Can you join flexible ducting?
In order to join two lengths of flexible ducting together, you will need to use a male connection piece. There are different flexible duct connector sizes available, you will need to use the corresponding size to suit the size of your duct.
What is the max recommended length of flexible duct?
5 ft
The ASHRAE 2009 Fundamentals Handbook (page 21.7 and 21.18) reads that “for commercial systems, flexible ducts should be… no more than 5 ft in length, full stretched.” 2. This is also included in the more recent 2013 handbook; however, the limiting length recommendation was changed to 6 feet.
Is rigid or flexible duct better?
Flex ducts are better for existing trunk-and-branch heating and cooling systems. This is because they’re more versatile and flexible. Metal ducts are more rigid due to the nature of steel, making them ideal to build an entire HVAC system.
Is it better to undersize or oversize ductwork?
Using oversized ducts will erode the system’s efficiency, while undersized ducts won’t carry the necessary volume of air. Balanced airflow. To maintain neutral pressure in the HVAC system and throughout the house, the duct system must deliver and return a matching volume of air.
Can duct work be too big?
Too big – Oversized ducts will give the heated or cooled air they carry more time to come to room temperature before they get through the vents and into the room, so you’ll end up with less heating or cooling where you want it, and the system being overworked to meet demand.
Does reducing duct size increase pressure?
If you reduce the opening of one register, you increase the resistance of the whole system. This increases the pressure of the whole system and reduces the volume of the whole system.
What is the disadvantage of flex duct?
The downside of flex ducting is that it is considered temporary with an acknowledged lifespan of only about 15 years. Another major disadvantage is that they are a little too flexible, so they are often incorrectly installed. And with greater friction than metal ducts, proper sizing is critical.
How do you join a rigid duct?
Quote from the video:
Quote from Youtube video: Side is good and what we need to do is you need to crimp this side. So that we need to put an elbow on well as you can see factory.
Does Flex duct reduce airflow?
If you’ve ever seen kinked or sagging flex duct and wondered whether that was a problem, you were onto something! Since flex duct, by definition, is flexible, it often flexes in ways we don’t want it to. The result is poor airflow and ineffective HVAC systems.
What are some of the limitations on the use of flexible air connectors?
The proposed code language
It says, “Length limitation: Factory-made flexible air ducts and connectors should not be more than 5 feet (1,524 mm) in length and shall not be used in lieu of rigid elbows or fittings.”
How often should flex duct be supported?
every once 4 feet
Supports should be installed at least every once 4 feet. The maximum allowable sag in flexible duct is one-half inch per foot. (Source: Calcs Plus.) Place supports at each connection between flex duct and rigid metal duct.
Can you run flex duct vertically?
5. Vertically installed duct shall be stabilized by support straps at a maximum of 6 feet on center. NOTE: Factory-made air ducts may not be used for vertical risers in air duct systems serving more than two stories.
What is the maximum length for flexible air connectors?
The length of a “flexible air connector” is limited to 14 feet maximum. The length of a “flexible air duct” is not limited in length. For a complete listing of the limitations of use of flexible air ducts and flexible air connectors, refer to the manufacturer’s installation instructions.
Should flex duct be insulated?
When flexible ducts are located outside the conditioned space, they should be sealed to prevent loss of conditioned air and also insulated to prevent thermal loss or gain from the ambient air. All ducts, whether rigid or flexible, should be sealed with UL-181–rated duct mastic.
Can you splice flex duct?
Two pieces of flex duct can be spliced together with a metal sleeve. Pull the ducts over the raised beads at each end of the connector, fasten the inner coils with nylon draw bands, mastic the seams, then pull together the insulation and outer liners, tape the seams together, and cover the tape with more mastic.
Can you use flex duct for cold air return?
Yes, you can use flex ducts for your return air.
