Greetings,
Hmm...All this makes me ask myself if sewage pumps can be run in reverse???QUOTE]
Actually, that reminds me of a stay we had in Knight's Key RV park (sorry, it's an RV story, but relates to RT's comment above.) Anyway, Knight's Key RV Park didn't have sewers at each campsite, rather a dump station, or in this case, a guy who drove around in a Honey Buckey wagon to pump out your RV black and grey tanks so you didn't have to relocate to the dump station. It was a paid service, but reasonable. Anyway, I happened to be wandering by and was interested in how the wagon worked. Actually a trailer pulled by a tractor. Trailer had a large poly tank, probably 500 gallons, with a sump, a pump, and associated hoses. The operator was explaining to the couple who owned the Integra Class A Coach that in order to prevent the RV tanks from collapsing, when the effluent was sucked out of the black tank, it was best to hold open the valve that flushes the toilet in order to provide a 4" or so "vent" to provide make-up air when the tank was emptied. So the wife dutifully went inside, into the toilet and yelled "Okay, it's open" You guessed it . . . the operator mistakenly placed the control lever in the position that was used to empty the large tank into the sanitary sewer, instead of to pump OUT of the RV and INTO the trailer tank . . . In order to hold the toilet valve open, the wife had to place her foot on the flush pedal of the toilet, . . . placing her head about 4' directly above the opening in the bottom of the toilet . . . The operator engaged the pump and after about 15 seconds or so, there was this absolutely hideous shriek of panic, combined with a healthy dose of despair as the contents of the trailer tank was pumped INTO the RV, filling the tank, and fountaining all the way to the ceiling, at least that that wasn't diverted from striking the woman's body and face . . .
. The operator realized what had happened, reversed the lever and pumped the tank out. The woman came tearing out of the RV, covered head to toe in . . . . let's say effluent, and crying/swearing. I figured that was a good time to leave. I heard later that about 3 to 5 gallons of "stuff" was pumped into the RV toilet space. Not sure exactly what the outcome of the whole deal was, but it was maybe 5 years ago. Heck, maybe in another 15 or 20 years she may be able to laugh about it! . . . Or maybe she's still in in counseling, and never stepped foot in that or any other RV since. . . . .
So, long story, but short answer for you, RT, is, in this particular case, THIS sewage pump CAN be run in reverse!