For proper furnace operation, what should the manifold gas pressure typically be?

The typical manifold gas pressure for proper furnace operation generally falls within the range of 3.0 to 5.0 inches of water column (in. W.C.). This pressure range is crucial because it ensures that the gas flow is adequate for combustion within the furnace, leading to efficient heating and optimal performance. A pressure that is too low could result in insufficient gas reaching the burners, causing incomplete combustion, while a pressure that is too high could lead to unsafe operating conditions and potentially damage the furnace.

Maintaining the manifold gas pressure within this range ensures that the furnace can operate effectively, providing reliable heating while also staying safe and efficient. Therefore, for any technician working in HVAC, it's essential to understand these pressure specifications to ensure proper furnace installation, maintenance, and troubleshooting.