I purchased a doran fan and 2 louvers recently and installed them in my darkroom.

I've printed about 4 or 5 times over the last two weeks and always at night.

I went in today during the afternoon and found light pouring in thru the supposedly light-tight louver.

Any hints? Did I install it wrong (I did follow the instructions). Can I fix the louver? The one on the fan is perfect.