Can I adjust this water feeder?
Chances are the float is dirty which will cause overfilling. My old boiler had the same water feeder and I had to take it apart a couple times a year to clean the float. Rust and scale from the boiler water can stick to the float and housing. Refer to the web page below which has a link to a drawing that shows how to disassemble the unit. It is not a difficult task and be careful taking it apart because there is an O-ring that can be damaged. Clean all the parts with soap and water then reassemble. If it still overfills then it might be time to replace the unit.
