MCC-NH Gas Fitters Practice Exam

What is considered the normal manifold pressure for LP gas?

1. 5"w.c.

2. 8"w.c.

3. 10"w.c.

4. 15"w.c.

The correct answer is: 10"w.c.

The normal manifold pressure for LP (liquefied propane) gas is commonly understood to be around 10 inches of water column (w.c.). This pressure is crucial for the proper operation of appliances designed to run on LP gas, ensuring they function efficiently and safely. Maintaining the correct manifold pressure is essential because it affects the gas flow rate entering the burners and ensures that they achieve the desired flame characteristics. If the manifold pressure is too low, appliances may not operate correctly and could suffer from incomplete combustion, potentially leading to safety hazards and inefficient fuel usage. Conversely, excessively high manifold pressure can result in a dangerous situation due to overly rich mixtures and increased carbon monoxide production. The range of pressures referenced in the other options, while potentially applicable in different contexts or with specific appliances, does not align with the standard and operational expectations for LP gas systems. Understanding these specific measurements and their implications helps ensure safe and effective gas fitting practices.