water tap, but nothing from cold taps. I’m guessing that’s because the hot water tank has a bunch of water and therefore puts out a little pressure until the tank is empty?

I’m baffled as to how this happened and what’s going on. We left the furnace on 55 deg when gone, and it hasn’t even been super cold the last few days (we live near Park City). Furthermore, we live in a 6-plex townhome building and we aren’t even an end unit, so we’re insulated on both sides. Doesn’t seem like cold temps should be the cause. What else would cause this?