BadNick

Quite a few people, even technical professionals, seem to think that if water is moving it won't freeze. For example, the practice of letting water run at the end of a pipeline to prevent freezing is not based on the water moving, but rather that the near freezing water is expelled while warmer resupply water brings enough heat into the system to offset heat loss.

PS: where I work we manufacture freeze protection bleeder/drain valves so I deal with this issue often. Most locomotives in the U.S. and Canada have one of our valves on the engine block to protect it from freezing since they do not use antifreeze in locomotives ...antifreeze results in reduced heat rejection and therefore reduced power and even a couple percent = lots of $$$