NCI Article Library

High-Performance HVAC Resources

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...

How to Select a Spill Switch

Spill switches provide additional safety whenever barometric dampers have been installed on equipment by sensing heat that may spill from the flue. If the flue becomes blocked, or if the negative pressure in the room causes the chimney to back draft and begin...

PK Wadsworth, Solon, OH

Paul Wadsworth calls himself the Business Leader of the PK Wadsworth Heating and Cooling Company of Solon, Ohio. The title Business Leader in place of President or CEO was chosen to typify his planned approach to business, as compared to the reactive approach found in...

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 Maintain Your Combustion Analyzer

The primary goal of combustion testing is to take readings you can trust so you can evaluate the operating condition of the combustion appliance. In order to take readings you can trust you have to be sure your combustion analyzer remains in tip-top shape. The...

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...

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...