A support system for an air handling unit (AHU) including a first rail supporting the AHU and a second rail supporting the first rail. A vibration isolator is disposed between the first rail and the second rail to vibrationally isolate the AHU from the second rail. The vibration isolator includes a spring secured between opposed spring retainers. An adjusting member threadedly receives the upper spring retainer. The first rail structurally carries the guide member along at least two positions. An angle is secured to the second rail, and the second end of the structural member slidably engages the guide member. Rotating the adjusting member with respect to the spring retainer in one direction compresses the spring between the spring retainers to support the weight of the first rail and the AHU. The angle constrains the AHU to movement along the guide member.