And, of course, the coolant in the tube will affect this–I can’t remember what the latest word is on what that’ll be, but I doubt the GF team are using pure water. Even if there is an antifreeze component, I’d still recommend a gate, if only for your own comfort/heating-cooling cost minimization.
Edited to cite @dan on this:
Not water: Water Cooling
Blast gate still recommended: Winter issues