At least with the 30s you have to be mindful of what you do when installing a coil assembly or you can have problems.
Unscrew the base ring. Unscrew the top cap.
When you install the new coil you need to make
sure the keyed coil base is aligned and fully seated in the keyed opening in the bottom cap. If it isn't aligned and is sitting on top of the keyed part of the cap instead...

Check it through the plastic tank - if the coil assembly looks at all crooked something is wrong.
Look at the coil assembly top down with the top cap still removed. Is it centered? If yes screw the base ring on, fill, and then screw on the top cap.