EPSON AcuLaser C3800 User's Guide
7. Take the new fuser unit out of its package and remove the protective materials.
8.Lower the new fuser into the printer making sure that the notch on the right side of the fuser unit into the post of the printer.
9. Lock the lock levers on both sides of the fuser unit.
Note:
Make sure that the lock levers are completely back to the locked position.
Replacing Consumable Products 236