NCI Article Library

High-Performance HVAC Resources

Flush the Tech Talk

Our customers are different creatures than they were a decade ago; and they're a whole new species than what they were in the 80's. Some of us old timers remember scribbling a model number and a price on a proposal, pushing it across the table and hearing them mumble,...

Flue Restrictors-Neutral Pressure Point

Let's say you are working on a furnace, boiler or water heater, and when you take a draft reading the draft goes off scale. This is a good sign you have plenty of combustion air but the excess draft can cause poor fuel-air mixture or increased loss of energy. Using...

Flow Hood Calibration Quick Check

From time to time you may question whether your flow hood is reading accurately. Most of the time, when you're using a quality hood like the TSI 8371, you'll find that even though you might be getting a questionable reading, the problem is not the hood, but the outlet...

Flex Duct Suspension Done Right

There's a time-tested method for suspending flexible ducting that's been gaining popularity around the country recently. It's quick, cheap and extremely effective. To multiply the effectiveness of your flex duct suspension, simply take a moment to slip a 12"x 12"...

Five Minute Duct BTU Loss/Gain Procedure

We've all heard our customers describe how their air conditioning system works O.K. in the morning, but doesn't deliver enough cooling in the afternoon. We send out a service tech, he services the unit and reports it's working pretty well. End of story, except our...

FisherAir Heating & Air Conditioning Services, Brea, CA

Alan Fisher, President of FisherAir Heating and Air Conditioning Services in Brea, California, was one of the first technicians certified by the National Balancing Institute (now National Comfort Institute) in the early 1990’s. His company has kept the flame burning ever since.

Finding Heat Pump BTU Output

It's 30 degrees outside and the heat pump is running. Let's say it's a 3 ton unit. What airflow should the equipment deliver through the system and what should the BTU output of that system be under current weather conditions? Last month, NCT included a HeatMaxx...

Finding Good Pulley and Belt Information

Two things are necessary to be effective in changing power transmission components. First is a good counter man at your local pulley and belt distributor. Second is accurate model numbers off of the components that you are replacing. Counter Man Forming and keeping a...

Find CFM By Measuring Coil Drop on New Installs

There's a fast test for a new installation that is highly accurate and takes just a few minutes. You can get system CFM by measuring pressure drop over a new coil. You simply plot the pressure drop on the coil engineering data sheet and read the airflow passing...

Do You Know How External Filter Racks Impact Total External Static Pressure?

Do You Know How External Filter Racks Impact Total External Static Pressure? A few weeks ago I was asked a question about finding the proper location to obtain the entering static pressure reading on an upflow gas furnace using an external filter rack. This is one of...