Chronic high vibration issue was being observed on a critical condensate pump. Although this motor driven pump is a standby unit, however, in case the running pump has a breakdown and this motor pump is unavailable, the Ammonia Plant will trip. This is a horizontal, overhung, centerline mounted, single stage pump. The pump was relocated to current site in 1992 and the problem of high vibration was observed after ~10 years of operation. The issue was observed around the timeframe when locally manufactured spares were used since OEM had discontinued offering its spares. The pump was overhauled 03 times in past 10 years, but the high vibration issue remained as such.