NCI Article Library

High-Performance HVAC Resources

Current Category: Tech Tips

Measure Fresh Air BTU Gain

Have you ever found an economizer with the louvers screwed closed or the linkage disconnected? There's a reason for that. There are days in the heat of the summer when the heat load of the fresh air makes it impossible for the system to keep up. The logical and...

Mark Damper Handles For Easy Rebalancing

by National Comfort Institute, Inc.

Ever balance a job only to come back and find out the homeowner or tenant decided to "rebalance" the system for one reason or another? By marking your damper positions when the job is complete you can easily tell if they were moved and easily rebalance the system by...

Magnehelic® Fundamentals

by David Richardson

The Magnehelic® is the go-to test instrument for many NCI-trained technicians for measuring static pressure. This test instrument has been around the HVAC industry for decades and is still the test instrument of choice for many. In this article, we explore the basics...

Learning How to Test

by Rob "Doc" Falke

The last couple of days I've been on a number of phone conversations with a great HVAC contractor who is just learning to balance kitchen exhaust systems. He's new to air balancing, but committed and eager to be good at it. I've been impressed with the learning...

Know Your Flue Temperatures

by National Comfort Institute, Inc.

Whenever you're servicing or starting up heating equipment, it's important to know what discharge temperatures should be in the outlet or flue. Our industry often teaches that the lower the flue temperature, the more efficient the equipment will be. Most combustion...

Keep Your Techs Safe During the Summer Heat

by National Comfort Institute, Inc.

Do you have a program in place to make sure your techs and installers protect themselves from heat exhaustion or worse in the steadily climbing summer temperatures? Here are a few tips to keep your crews healthy and productive this summer: Provide temporary cooling in...

Installing Dampers in Finished Ceilings

by National Comfort Institute, Inc.

There's nothing more frustrating than not being able to balance a system when it was built without balancing dampers, and the plenum and take-offs are behind a finished ceiling. Here's a little trick we use to install dampers on critical ducts in finished basement...

Induced Draft & Atmospheric Common Venting Interference

by Jim Davis

When an Induced Draft Appliance (Furnace, Boiler, Water Heater) is "Common Vented" with an Atmospheric Appliance, venting interference can occur. This procedure is the proper method to evaluate this situation and take all precautions to verify safety. Necessary tools...

Increase Temperature Measurement Accuracy

by National Comfort Institute, Inc.

When measuring system or equipment temperatures, take your measurements as soon as the system stabilizes. This will allow your performance calculations to resemble (as close as possible), normal operating conditions. In order to keep the system running during testing,...

How to Select Your First Water Balancing Gauge

by National Comfort Institute, Inc.

When it's time to take your first try at measuring the performance of a hydronic system, you might want to begin with some starter instruments. A hydro- manometer like the big boys use normally costs over $3000.00 each. Although well worth it, you may not want to part...