Operational Issue: Excessive gas pressure drop

What does Pressure drop greater than permissible mean?

If the gas pressure drop in the system exceeds the limits set by the National Fuel Gas Code (0.3, 0.5, or 3.0 inch W.C.), the water heater may not operate correctly. This is often caused by undersized piping or faulty regulators.

• Gas piping too long or too small
• Incorrect regulator settings
• System pressure below required minimum

Click steps to track your progress.

1. 1

   Measure the inlet gas pressure to the system using a manometer.

2. 2

   Compare the measured pressure drop to the allowable limits (0.3, 0.5, or 3.0 inch W.C. for natural gas).

3. 3

   Check gas pipe sizing calculations against the manual's tables.

4. 4

   Ensure the gas supply meets the minimum pressure requirements (e.g., 8.0 inches W.C. for Natural Gas).

5. 5

   Contact a qualified professional if pressure drop issues are detected.