Mine also has the 2 low point drains and a separate big valve to drain the water tank.
Don't trust the 2 low point valves to get all the water out of the system when you winterize. I still use compressed air thru both the sinks to clear out all the water. Same with the tank drain. I open it and drive around the block to get the last bit to slosh out.
Mike in Colorado
2004 Fleetwood Pace Arrow 37c, 8.1 gasser, (Jezebel) Ultra RV ECM / TCM, plugs wires, and rear track bar, PPE deep Tx pan, Bilstein's, Sailun's & Sumo's all round, pushed by a 2002 Grand Caravan, on a Master Tow Dolly.