May 20, 2007, 6:38 PM
Post #9 of 10
Rolly, when you get into ductwork, there are many things to know about that are not obvious to the layman. It is a trade, and like most of them it takes special training and education to do the work properly.
Moving air, unlike water or electricity does not take the path of least resistance. Turning vanes, and balancing dampers must be used inside the ducts to direct the direction the air moves in. Sometimes a simple scoop will be fabricated to catch some of the air and direct it into a side duct.
When a square, or rectangular duct makes a 90° turn, turning vanes must always be used to direct the air around the turn. If the turning vane is not used, some of the air will get around the turn, but backpressure will be created, and the flow rate of the air will be reduced.
A balancing vane looks like a heavy duty metal Venetian blind, with unmovable vanes. A balancing damper is a type of valve for the air that can be partially closed or opened.
There is a profession that specializes in balancing the air and heat flow in buildings. They usually only will be seen working on very large projects after all construction has been completed. They are called by the not surprising name of “balancers”; it is a very specialized occupation. They adjust the flow rates of all the heating and cooling pumps, duct systems, and the air handlers. An air handler is a large fan system used in large HVAC systems. Often, the air handlers are so big that you can open an access door and walk inside of them.
Next to a bird feeder, a house is about the simplest structure you can build. Mistakes and shortcomings are often not noticeable to a layman. If the airflow problem in your Las Casas project is troublesome enough, it might be wise to have the contractor that did the ductwork at Doña Martha’s house look at the work to possibly correct any shortcomings.
It is very hard to find a truly qualified tradesman or contractor in México. I have yet to find one that didn’t claim to know how to do anything I wanted done. Some of them have been pitifully lacking in knowledge, experience and ability.
"The supreme happiness of life is the conviction that we are loved" - Victor Hugo