Hi Shari and welcome to the forum. If it was freeze damage I too would think it would show up as soon as you turned it on, not 3-4 weeks after. At this point all I have are some questions. Is it a top or side mount valve assembly and what is the filter make/model? Reason I ask about top/side is the internal plumbing is different. The way you mentioned the 'center pipe' it sounds like a top mount. Also, what kind of a break was it and was it the same both times? Describe it the best you can.
Al