ball valve half-open to avoid winter freezing?

I'd appreciate if someone can give a quick answer to this quick question:

Say it's impractical for some reason to drain a part of a water system -- instead, water is left running to reduce the risk of freezing (this system is located in a climate where daytime winter temperatures are usually above freezing and nighttime temperatures are sometimes a few degrees below freezing). The pipes are HDPE, so an occasional freeze shouldn't be a problem. As for the ball valves: would it reduce the risk of valve cracking if I leave the ball valves half-open?

Thanks Received on Mon Oct 15 01:21:00 2007