Embodiments and methods are disclosed herein that relate to a valve assembly. The valve assembly includes a housing having a passage formed therethrough, and a valve ball having a through hole and disposed in the housing, in which the valve ball is rotatable between an open position that has the through hole aligned with the passage and a closed position that has the through hole misaligned with the passage. The valve assembly further includes a seat having a first tapered surface and disposed in the housing adjacent to the valve ball, wherein the seat is biased towards the valve ball, and a seat holder having a second tapered surface and disposed in the housing adjacent to the seat such that the first tapered surface of the seat is disposed adjacent to the second tapered surface of the seat holder.