On mine when new it would overflow. I just raised the overflow tube to the top of the compartment. I then drilled a couple 3/8 holes in the compartment floor. Thus giving me those holes plus the one the overflow tube came out of for any water that might get in there a place to get out. I can
fill tank 100% no syphoning.
I don't understand why FR put that crazy door on the water compartment with silly latches on the underside??
I cut a 6" round hole in the compartment wall in front of the water tank. The hole has a screw in plug if one would want to use it. I just open the compartment door in front of water tank and watch the tank fill. Thus never overfilling. I ll attach a picture. Picture will show water tank on other side of wall. Tank has maybe 2" of water in it.