Water pushing out of city water connection.
I was recently winterizing my motorhome by putting some RV antifreeze in the water holding tank and pumping it through the lines using the RV water pump. I noticed that it was pushing some antifreeze out of the city water hookup. I have used the holding tank water before and never had this problem. I assume the system uses a backflow prevention valve. When I was winterizing, the pump was pulling some air as well as the antifreeze, could this be the problem?
2004 Thor Mandalay 38B