NCI Article Library

High-Performance HVAC Resources

Current Category: Tech Tips

Getting a Diagnostic Test From a Service Call

Besides the valuable information the reading provides to help resolve the service call issue, it can be a prime lead-in to selling a complete system diagnostic and potential duct renovation work. To provide your customers with air conditioning systems that perform as...

Gas Pressure Adjustments Done Right

by Jim Davis

Whether starting up new equipment or servicing existing equipment you should never assume that the recommended gas pressure of an appliance will assure safe or adequate operation. Performance cannot be determined until combustion testing has been completed. There are...

Flue Restrictors-Neutral Pressure Point

by National Comfort Institute, Inc.

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

by National Comfort Institute, Inc.

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...

Duct System Installation Don’ts

by National Comfort Institute, Inc.

"Air doesn't do that!" is a common phrase uttered at NCI during seminars and tech support calls. When it comes to delivering the required airflow there are several field conditions that will cut the airflow short every time. Lonnie Robnett of Nevada Heating has...

Dress Up Your Duct Sealing

by National Comfort Institute, Inc.

Most of us who seal metal ducts using mastic know how hard it is to neatly brush the mastic on joints. This is no big deal on ducts in attics or crawl spaces, where they'll never be seen, but can look kind of sloppy on exposed ducts in basements and equipment rooms....

Does CO Certification Impact Your Liability?

by Jim Davis

What's my liability when I make the job right? This is a commonly asked question once contractors are taught how to diagnose and fix combustion safety and efficiency problems. My first response is another question: "Does ignoring or not diagnosing problems reduce your...

Diagnosing Water Heater Pilot Defects

by Jim Davis

Trying to solve water heater pilot problems is one sure way to experience feelings of frustration and uncertainty. The challenge is to learn to recognize all the conditions that can cause them to go out and then quickly bring to mind the host of repairs available to...

Diagnosing Cooling Systems

by Rob "Doc" Falke

Compared to the majority of the service techs in our industry, airheads have a distinct advantage when it comes to diagnosing cooling systems. The general idea that the system is "working" means it's typically only producing 60% or less of the equipment rated BTU...

Diagnosing a Long-standing Water Heater Pilot Problem

by Jim Davis

It appears that certain water heater pilots may have been undersized in the field for the last 15 years or more. For over a decade we have received reports from NCI technicians working on pilot outage problems finding pilot orifices sized for propane pilots on natural...