Matt Ruggeri
New Member
As others have said - Negative Pressure. My install is similar to yours, and we had this problem for the first 2 seasons. It would only happen when the barometric pressure was low (during rain/snow) it was annoying, and aggravating! The first, and cheapest solution worked for us (broken link removed to http://www.woodlanddirect.com/Vacu-Stack-Wind-Resistant-Chimney-Cap?gclid=CPiThrjh-LsCFaE1QgodDwUASw?gdftrk=gdfV23673_a_7c1677_a_7c8224_a_7c1161016_a2s__a3a__a2s_1161018#Vacu-stack%3A6%22)!