What incubator are you using? How are your temperatures? Still air or forced? Have you calibrated your thermometer? How long has the one that pipped been pipped for?
Sorry for the 20 questions but more info will help us help you
Quick edit, I read your other thread and will paste it here for others to see:
Firstly your temp is low. If you are running forced air it should have been at 99.5 degrees the entire time, making your temp a full degree and a half low. If still air, you are three and a half degrees low since the temp should be 101.5 measured at the top of the eggs for still air. These low temperatures could certainly cause your late hatch. Your humidity also has been a little high. Personally I incubate at 30-40% humidity for the first 18 days and no higher or my chicks drown in the shell. Unless they're bantam eggs, which do need a bit more humidity.
The one that has pipped hasn't been pipped long enough for you to worry. Let it be and hopefully it will hatch on its own in the next 20 hours. If it gets to 24 hours with no progress then you can start to worry.