Originally Posted by richardr
We have an Escape 21. I think the tubing running under the trailer goes to the sink. If I leave the sink faucet open (pump off and not connected to city water), would that protect the tubing if it freezes? (We have the under trailer insulation, but I'm not sure how much this helps.)
Yes, this helps. By having an open faucet, the freezing water has a place to expand. Water expands when it freezes, and it is this expansion which causes pipes to burst or fittings to fail.
But this technique is not foolproof. It is still possible, for example, for a section of pipe to freeze both in front of and behind another unfrozen section. Then when the middle section goes to freeze, it is trapped and cannot expand.
The only real way to avoid freezing/bursting pipes is to evacuate all the water with air pressure, or replace pure water with anti-freeze which lowers the temperatures at which freezing occurs (to like -20 or -50F, depending on which type used).
It is a matter of weighing the risk of pipe or fitting failure, which could be inside a wall or other "very" hard to reach location, against the effort to winterize. All in the window of how likely to freeze: temperature, is it enclosed, do you have the insulation, is there a heat source, etc.