The TM is designed for quick and easy winterizing. My 2002 2619 has 4 petcocks. Two up front and two at the rear near the screwjack. One at the front empties the 20 gal fresh water tank. The other one empties the water from the plumbing ( fresh water from the "high pressure camp water connection". The two at the rear empty the remainder of the water in the hot and cold water pipes. This is what TM calls the low point drain system. To empty water from ALL my pipes, I simply go inside the trailer, open the hot and cold faucets in the kitchen, bathroom lavatory and bath tub. This prevents a vacuum and lets the water drain freely. Now I go outside and open the front petcock and hot and cold water begin flowing. Then I open the 2 rear petcocks, open the hot and cold faucets at the outside shower and watch as the remainder of the hot and cold water in the pipes drain.
If you're draining the pipes for winterizing, you need to remove the hand held faucet from the outside shower and stow in your garage or home, so It wont freeze, and add a little anti-freeze to the kitchen, bathroom lavatory and bath tub drains. That's all there is to winterizing. I think. And if I've left something out, some one will come along and tell us what I missed.
The water heater has an annode rod that needs replacing on a regular basis, It takes a 1 1/4 inch socket to remove this. When you remove it, you will also get some water draining from the heater.
Since the 2720 has different plumbing runs than the 2619, perhaps some one else has better info on the 2720
hope this helps
