If you got The Vest first hand you should give Hill Rom a call. I'm under the impression that there is a "lifetime warrantee" on The Vest, including the tubes and the actual vest.
My vest was fully paid for by insurance about 10 years ago. (It did take about three years of monthly payments before it was paid for.)
Over the years, Hill Rom has replaced the vest and tubes a number of times. This past year, after several thousand hours of use, the 104 itself stopped working. Hill Rom replaced it with the newer model 105.
Hill Rom has always been extremely pleasant and helpful whenever I've called.
Good luck.