The 1007 is pretty easy to dewinterize, as everything you need is really close together. The valves and low point drains are all situated right with the pump, just to the right of the sink cabinet, under the front dinette bench. You will also need access to the water heater valves, those are located under the bench to the left of the sink cabinet, but you may have to pry up on the lid; ours was originally screwed shut, and didn't have a pull hole drilled.
RogerR's process is fine, but a couple of additional points.
- Check to make sure the winterize valve (to the open ended tube) is fully closed (mine was open a smidge one year and took a while to figure out I was sucking air into the system)
- Open the valve to the FW tank (the hose goes down into the floor) to ensure you can draw in fresh water from the tank. It is probably still closed after winterizing. Also make sure that the particulate filter just before the tank is clean and the cap is on tight.
- Check the plug on the water heater and the relief valve to be sure they are closed. If the plug is out, you might want to use a HWT wand to clean out the tank first.
- I put a bucket under the low point drains, and open the sink drain cap on the outside of the camper with a short length of hose into the same bucket.
- Pop the low drains and open the faucet and/or outside shower to gravity drain back the antifreeze. Close again.
- Hook up a hose to the city water supply, and turn on low pressure (or use a regulator).
- Open the low point drains, and the faucet and shower again until the rest of the pink pumps out. Let it run for a bit to be sure all is gone.
- Open the hot tank bypass to fill the tank with fresh water. Pull the relief valve cam up until water spurts from the valve (tank is full).
- Now you might want to sanitize your system with bleach as mentioned. This uses the water tank, and will also prime the pump for the year. Let it sit 4 hours, then dump and thoroughly rinse again. Lots of instructions on this here.
- Finally, remove the bypass hose and reinstall the water filter (behind the sink in the flip cabinet). I put a new one in every two years, but we don't use much water indoors, should usually be replaced annually. If using a fresh cartridge, run water through it first from the hose to flush out any carbon.
Sounds like a lot, but in reality it is about 30-45 minutes (not including wait times for sanitizing) once you know your way around. I just finished mine on Sunday afternoon, along with all of my other preseason trailer maintenance and stock up.
Now you are dewinterized, sanitized, and ready for another great camping season.