MrWizard wrote:
Back flow check valve ?
You got a bypass situation somewhere
Time to trace your plumbing with a stethoscope while listening for the water flow, you can get a cheap engine mechanic steh at harbor freight
OK, I may be learning something here (old dog-new trick).
I thought of back flow for the pressure change the OP says they hear, but discarded it because of the tank filling question. Backflow would drain back into the tank, or possible out a low point drain---not into the gray water tank. Correct????
Plus, they are hooked to city water (so they say) and the mere pressure of the system would prevent backflow---constant pressure.
