Natural gas pressure is not evaluated only when the burner or appliance is stopped. The most useful insight comes when comparing static and dynamic pressure.
Static pressure
It is the pressure when there is no significant consumption or when the flow is very low.
Dynamic pressure
It is the pressure while the installation is consuming gas. This shows whether the network can actually supply the required load.
Why there may be a significant difference
Small pipe cross-section, a clogged filter, a restriction in a valve, or insufficient regulator capacity can cause a drop only when there is flow.
Correct diagnosis
Measurements must be taken at the same point and compared at different loads so that the behavior of the network can be clearly seen.
