Just to clarify, I'm talking about the gas pump that pumps oxygen to 2 of my rooms. I added a valve to combine the output of 2 pumps. That much works fine. But when I added two other valves to further control the output into the 2 separate rooms, then the gas seems to get blocked somewhere along the line. I know one of the vents is being overpressured, but does that really affect the whole system?