The fresh water tank is filling when I hook up to the water system. Does anyone identify with this problem? There must be a check valve leading and I don't know the location of it.

Thanks, Charles Phleps

There's a check built into the pump that most likely has sediment/scale in it, probably run the pump awhile to wash it out, if not there's also a valve at the pump from the fresh water tank you can close it, just be sure to open if using the pump.