NCI Article Library

High-Performance HVAC Resources

How to Red Tag a Defective System

How to Red Tag a Defective System When following National Comfort Institute Carbon Monoxide and Combustion Efficiency Protocols and procedures there is a chance a dangerous or potentially dangerous condition will be uncovered. If this happens, there are times when...

How to Determine Combustion Air Performance

Combustion air testing is performed using a draft gauge and a CO analyzer. When the draft in the flue of an appliance is low or below -.01" to -.02" W.C. and when CO reading are rising, combustion air problems are present. Carbon Monoxide diagnostics consistently...

How to Adjust Barometric Dampers on Gas-Fired Appliances

The procedure and purpose for adjusting barometric dampers for gas appliances is completely different from the reason you adjust barometric dampers on oil equipment. Let's take a look at each method to get a clearer picture of what we're trying to accomplish. OIL...

Hard to Pinpoint CO Problem? Narrow It Down

Have you ever noticed a distinct change in CO readings when the blower comes on? Most technicians believe this indicates a cracked heat exchanger. But could it be something else? There are at least three scenarios that could cause this situation on Natural Draft and...

Generate New Work With CO & Combustion Testing

In addition to keeping your customers safe and saving them money, CO and Combustion Testing can be a very lucrative source of revenue for your contracting company. One of the main benefits of testing is the repair work it generates. These repairs are offered by few of...

Gas Pressure Adjustments Done Right

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...

Introducing NCI’s New Service Proposal

How many times in a week is your service technician placed in a situation where he or she finds a problem with a customer's system and when he approaches them with their options they're upset with the unexpected expense? You're stuck explaining options until they...

Induced Draft & Atmospheric Common Venting Interference

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...

Adjusting a Ball Valve on Intake of 90% Appliances

Adjusting a Ball Valve on Intake of 90% Appliances by Jim Davis, NCI Senior Instructor In our combustion diagnostics class, we discuss short flues on condensing equipment as causing possible venting problems. We recommend adding a plastic ball valve to the intake of...

How to Use Yellow CO Tags

Last month we brought you a red tag label that you can attach to an appliance when you disable it due to a safety hazard. This month we bring you its cousin, a yellow tag that is to be attached to equipment when you have made modifications or repairs to improve the...