NCI Article Library

High-Performance HVAC Resources

How to Size a New Fan Belt

When you spin an adjustable pulley and increase its diameter to squeeze a little more air out of a belt-drive fan, there are times you'll find the old belt no longer fits. The first fix is to loosen the bolts on the motor mount and slide the motor as close to the fan...

How to Redesign an HVAC System – Part I

We've looked, but can't find it. There are mountains of information about how to design a new HVAC system, but nothing much that addresses how to redesign an HVAC system. It would take hundreds of pages to completely detail the process, but let's take a stab at the...

How to Plot Fan Airflow

How to Plot Fan Airflow by Rob Falke To be well prepared for this new level of diagnostics, begin collecting copies of the fan data found in most installation instructions for the equipment your company installs and services. The most important diagnostic truth about...

How to Measure Commercial System Efficiency

How to Measure Commercial System Efficiency by Rob "Doc" Falke, President, National Comfort Institute It’s just not fair. Some contractors have a distinct advantage in the marketplace over their competitors; they ruthlessly and knowingly measure the live operating...

How to Interpret Fan Performance Data

One test essential to successful CoolMaxx™ service reporting is interpreting fan airflow from the manufacturer's fan data after you measure total external static pressure. As with most HVAC system diagnostic testing, it takes more than textbook learning to become an...

How to Implement CoolMaxx for Maxximum Success

Since the heat has settled over most of the country we have had an increasing number of calls reporting a wide range of methods of implementing the CoolMaxx report. While many of the variations are interesting, after a discussion of how we intended CoolMaxx to be...

How to Generate Leads With HeatMaxx™

Ok, so you've trained your techs on how to test initial system performance with HeatMaxx™. You've got the forms and the right tools. So how do you generate leads form your service calls, and just as important, how do you follow up a lead from a low-scoring HeatMaxx™...

How Airflow Affects Heating Efficiency

Airflow is critical to proper heat transfer in heating and air conditioning systems. Most of us know the rule that temperature drop over a cooling coil should be 18 to 22 degrees. If the temperature drop increases, it is evidence that airflow is low. If the...

Heat Strip BTU and Performance

Since the cold has set in we have received many calls and e-mails on PerformanceTalk from contractors and technicians wresting with electric heat systems. The two main topics discussed are: How to determine and rate electric heater performance and how to figure the...

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...