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Good evening wallies,
Writing up a small paragraph and posting two videos in hopes someone has come across this issue before and can lead me in the correct direction.
Have a small building with two 600mbh condensing boilers. Two inch gas line from the street to the boilers. Low pressure in the street so there are no regulators. Gas main has a wye strainer which is clean and removed the basket for testing with no relief, so it was re-installed. Meter is a rotary style meter that is brand new due to me thinking it was the cause of the nuance spikes.
The first video is when only the commercial 160mbh dryer is running. Second video is when only a single boiler starts up and runs. The only thought I have is that there is water in the line however the drip legs were dry other then a few drops of oil. When one boiler is on, the second will lock out intermittently due to an unstable gas pressure. No regulators on the line. Gas company says they did their job as there is six inches of water column at the meter.
Hopefully your internet connection is fast enough to see the needle vibrating.
While I have you guys here, can anyone assist in sharing a source or pdf that illustrates and instructs how one can oversize a NG line to compensate for not enough pressure on start up? General gas sizing information would also be helpful as I can use a good brushing up on pressure drops, fittings and line length.
The boiler company said we need a pressure booster since the street cant deliver over seven in-wc. Never heard of such an apparatus.
Comments & suggestions welcome.