I suppose it's possible it froze but I don't think so. As far as I know, it never got below 32 in side. We kept a heater hooked up all winter, and this winter wasn't as bad as last winter. I know the natural gas usage this year is way down from the same period last winter.
What I found interesting was no O ring was to be found on the water valve I removed. There should have been one, and I would think there was one, but I didn't see it upon removal of the module.
The new module had a red O ring.
DavidP wrote:
The typical failure of the vacuum breaker is a small amount of water seeping past the o rings in the valve and making it past the vacuum inlet. This results is a little water making it to the floor after filling the bowl and not so much from a quick flush. The fact yours sprayed water once put back in operation is most likely from freezing and cracking.
I did have to replace mine twice but the last one has been in there several years. In talking with Thetford several years ago when replacing for the second time I was told a change was made to address the problem. Since then it has been fine. Either way this does not seem to be what your problem was. Pink stuff is your friend.