The key is to get all the fresh, waste, or salt water out of the bowl, supply line, and discharge line. That water is replaced by pink, non-toxic antifreeze to prevent the lines, pump, fittings, or bowl from freezing and cracking.
You'll need to trace out the plumbing in your system as they can vary. Here's what I do on mine:
Pump the bowl as dry as you can get it.
Remove the supply line at the seacock (if the boat is in the water, make sure the seacock is closed! If the boat is out of the water, open seacock to drain water.) Place supply line in a bucket partially filled with pink antifreeze (full strength).
Pump the toilet and watch for antifreeze to appear. Pump enough to fill the discharge line with antifreeze.
Reattach supply line to seacock.
If you've got a holding tank, it should be properly pumped out at a pump out facility. The pink antifreeze that is pumped into the holding tank will prevent freezing of any residual wastewater that remains.
Again, the key is to replace any fresh, sale, or waste water with pink stuff. As long as you trace out the system to make sure your doing that, you can't go wrong.
The same principles apply to the fresh (drinking) water system on the boat, too.
Randy
