Arkansas HVACR NewsMagazine January 2023

HVACR NewsMagazine January 2023

Tech News

a note of caution. About 80% of material on the internet regarding HVAC information, is either dated or in error. Many HVAC forums on the internet come up with inaccurate solutions to everyday problems. Measuring static pressure, air flow, humidity, and BTU performance is the only way to be sure your company delivers a quality product. National Comfort Institute has a two relatively new classes. One titled “System Design and Redesign” and “Refrigerant Side Performance”. Both classes focus on correcting bad duct and performance installs. Stepping back to Carrier Industries, some of their product lines today, require a wireless connection and a pin to access the controls on board. Soon to be gone, are the days of blaming another tech for setting up operation incorrectly. There are common identifiers that call out poor performance for us if we understand the issue. Large grilles and adequate surface area for filters is a first step. Static across the intake grille and filter media should not move past .15 psi. In most instances two media filters are required to keep velocities at or below 300 FPM. During sales and technician training display pieces of cardboard or posterboard cut to represent two square inches for every CFM a system will require to flow proper amounts of air. A nominal three-ton system will require 600 square inches of grille area. This will train your staff to immediately recognize inadequately sized returns. Air intake for the furnace or air handler should not be restricted in any manner. A reminder of performance in comparing square to round duct may be helpful. Once again, an internet web site can

help again. Engineering Toolbox has every possible calculator you might need understanding limitations of round duct vs. square, air velocity, air density and other common calculations. Setup of equipment with the correct fans speeds and timer selection must be followed to the letter of the manufacturer along with thermostat setup. The engineering team that builds furnaces and air handlers know how the system will perform, so trust and follow the setup instructions. Design and construction of distribution system is a point generally overlooked on sales or service calls. Understanding proper plenum design must incorporate an adequate takeoff area and rebound zone is important. The idea you can force air to differing points in duct system is downright foolish and wastes huge amounts of energy. We must remember we deliver air with low resistance and specific targets. We displace energy to cool the structure. We do not cool the air. The process is not hard; however, you must educate yourself and the folks on your team installing the equipment. You can’t singularly depend on hiring experience, because experience is retiring, and the overall industry has failed with few exceptions. Otherwise, we would not have 80% of systems underperforming at 60% of rated capacity. So, make a New Year’s resolution that’s worth keeping. Installing systems that perform at 90% or more of rated capacity is a game changer for you and your company. The year 2023 is the year to understand how to immediately identify shortfalls for duct and distribution systems and learn how to extend the life of evaporators with filters that perform.