Part No. MAN, Rev. EH. Wachs 5. At the control panel, turn the pressure washer switch to the WATER position. The water in the sprayer system will flow from the hose into the priming tank. Figure 4-6. Turn the pressure washer switch to the WATER position. 6. When the antifreeze mix begins to come out of the nozzle, turnoff the engine. 7. Open the brass drain valve at the back of the trailer and drain all water out of the water tank. Figure 4-7. Open the drain valve on the back of the trailer to drain the water tank. 8. Open the top of the water tank and use a wet vacuum to suction any remaining water out of the tank. 9. Pour an appropriate antifreeze mix into the water tank, to a depth of about 1 inch.