Weil Mclean boiler maintenance Question

Hi, I replaced the ignitor on my sister in-laws Weil Mclain boiler model HE - 11 -4. The boiler fired up and seems to be working fine. I opened the valve on the left side of the boiler to check the condition of the water and it was dark brown. I did this several times filling a small container and it still comes out dark brown. Should I be doing this until the water becomes clear? I don't think it has been done in years. She lives by herself and has never done any maintenance on the boiler. Doug