For the last 6 winters I have simply turned on the faucets and started the washer to fill the tum with water. I do that using the water pump like I was pumping antifreeze through the system. Remember no matter what you have to be sure that the washer has anti freeze in it, or else you run the risk of damaging the water pump in the washer.
Might help if you told us what make of w/d you have. Procedures could differ. If you have a Splendide this should help you out.
__________________ Happy Camping! ///// Richard D.
2006 4x4 Ford 250 SD / 2007 Flagstaff 827 FLS
One very patient wife and one furry child who travels with us. Forty-two years of trailering and camping, and I still have a blast.