I have a Utica Boiler (Honeywell) and I think my daughter (3 yrs. old) may have turned the two black valves that are above and below the glass water meter tube. I am not sure in what position the valves should be -- open or closed -- but i now have noticed that the red "low water level" light switches on even though the glass tube is totally full of water.
If this is a steam boiler the valves should both be open. Counter clockwise is open. As far as the water leavel you should be able to see one somewere in the glass it should neather bee all the way full or empty.