Originally Posted by bubbles
...I do believe OC's factory install with 2 check valves was a fluke (there may be more)...
Or it could be the way 2012 Flagstaffs were produced and just maybe "bubbles" is incorrect in assuming they used the same flush system as his. Endless possibilities exist on how and why FR does things one way on one brand and totally different on another. Gljurczyk says his Rockwood does not have the inlet check valve like mine, and they ran down the same assy line. GO FIGURE!