efm round door does not close all the way

i purchased the efm used, it has a round door that will not close completely. i am still piping efm into existing gas hw system. worried about CO2 if door is ajar. any ideas or answers?

Do you have the correct size (thickness) gasket in the door?

not sure, this is my first time setting one up, it has the one that came with it. no model number on it so i don't know what size it should be

Check with Stoker-man assuming this is the issue. He can provide you with the correct size or you can probably order some from EFM. EFM is a great company.

The door uses 1/4" fiberglass rope gasket.