Arkansas HVACR NewsMagazine November 2020

S tate, National, Chapter News Tech News

first day they were installed and 9 of 10 times airflow is the issue. So, what is the solution? Stop making repairs, changing equipment, or installing new home HVAC without understanding the fundamental requirements to make the home livable and economical. In other words, “Stop Promising what the Equipment Can’t Deliver!” Assess the issues- Our society has become so dependent upon technology, we forget the best tool we maintain for engineering purposes are our eyes. Get used to understanding what underperforming equipment looks like. When training your staff on return air sizes, cut out poster boards that represent the size grilles required for proper airflow related to nominal tonnage. Poster board cut at 22-degree angles can be used to demonstrate transition requirements to maintain air flow without robbing the system of necessary static pressure. Assess the duct system to validate whether the duct is routed carefully with sweeping turns and no reversed direction runs. On new home construction and equipment replacement think logically of how to position the furnace or air handler to minimize duct runs. In many homes a 90-degree swing of the equipment can reduce duct length significantly. We

must remember that it is easier to pull air than to push air even when ducts are sized correctly. Be sure terminal devices are pushing air toward targets for efficient and effective distribution. During cooling we push low energy air to walls and windows to displace heat. During the heating season we direct the air to those same targets, but the air is now energy laden. Tests prove high sidewall delivery of air to exterior walls, is the gold standard. Where high sidewalls are not available, curved blade ceiling devices must be employed. Contrary to popular belief, we are attempting to deliver low energy (cooing) and high energy (heating) air to contact surfaces like walls, windows, and doors. We are not cooling the air inside the home. When we deliver the appropriate amounts of air correctly run times can be reduced and likewise unit off times will enhanced due to loading the mass in construction materials. If duct replacement is a part of your scope, (and it should be) measure from inside the dwelling. Once these measurements are made move to the attic to make sure the duct is accessible to match your estimate. When we begin duct estimates in the attic, our ability to estimate accurately is hampered by a distorted view of distance due to limited views and space relations. Less wasted duct at the end of the day saves you