1. Apply a ¼" wide bead of high temperature silicone all around the boiler vent connection 1" from the end. Install 5" to 4" reducer on boiler vent connection. Secure properly with a clamp. 2. Carefully measure the required length of vent pipe and cut with a hacksaw. Allow for the two end adapters in your measurement. 3. Apply a small bead of silicone to the outside of the oil vent ends. Twist end adaptors to each end of the oil vent. Turn adaptors counterclockwise. Engage the outer cover of the adaptor evenly over the exterior of the vent pipe. Turn the adaptor until the vent pipe interior seats evenly against the expanded teflon gasket of the end connector. Secure adaptors to the vent pipe with the provided clamps.