May 16 2016 · Natural gas in the natural gas service line pressure in the gas main in the street will be found at pressures from 60 psi down to as low as 0.25 psi or about 7 inches of water column. Natural gas pressure at the meter: Depending on the application meters may operate at 7" w.c. 0.5 to 2.0 psig or at pressures over 2.0 psig.
Observe these valves as they open. At this point the pilot ignition system the flame scanner the action of SSOV operation and the high gas pressure switch have all been proven. Main burner ignition and flame establishment is also timed into the flame safeguard control depending on burner type and size.
Manifold pressure should be set at 3.5 in W.C. for natural gas. Control manufacturers normally preset the pressure regulator in natural-gas valves at the time of manufacture so that natural-gas units are fired at this 3.5 in W.C. rate. Only small variations in the flow should be made by adjusting the
Safety controls for any fuel gas fired boiler. If natural gas and air are inside the boiler when the burner is lit the boiler can explode. High Natural Gas Pressure: A pressure switch in the natural gas line stops the burner if the gets too high. If the control valve fails excessive can flow to the burner.