Hoss 350
My GSP, Dutch
Then it isnt a furnace setting that caused the failure, its poor insulation.
Maybe. Or maybe if it were 70 inside the house, that spot would have stayed warm enough to not freeze? I think that is where everyone is going with this. The pipes never froze while they were home, so my guess is that two things played a role here.
They were gone, so the temps were turned down inside enough that this poorly insulated area froze up, and also, they were gone so the water in the pipes wasn't moving, and stagnant water freezes right up. If you are using your pipes a lot, the water circulates enough to keep it from freezing.
In fact, one method to help prevent freeze-ups is to leave a faucet or two trickling while you're out.
However, my method is the best of all. If you are leaving for a while, shut the water off at the main shutoff outside the house, and leave your faucets open. That way, even water left in the pipes will have someplace to expand, and if a pipe does get broken due to freezing, the worst that will happen is a couple gallons (at MOST) of water will trickle out once the pipes thaw.