I've got natural gas flowing to a chamber with a regulator set at 9 inWC. The gas then goes through a mass flow meter with a 1/4" diameter hole, which causes a pressure loss of about 3 inWC (to verify this, I have another pressure gauge after the flow meter which accurately reads 6 inWC... After that gauge, it goes through a gas tube with quick-connects directly into a water heater. The tube is hefty, some kind of semi-rigid metal (not sure of the kind, can look it up) and the tube has a diameter of 3/4", and is about 8 feet long with two bends (90 degrees, but not sharp). My question is - would this pipe cause significant pressure loss? The water heater needs at least 4.5 inWC to operate. I wouldn't imaging this tube casing a 1.5 inWC loss, but I could be wrong. Any insight? Thanks.