The boiler is 9 years old, and a Scottish Gas C1 model.Best Answer title for first good answer! :)
You probably don't need me to tell you it's time to reseal the joint. What I can tell you is that it's very common to have water inside a boiler distribution system turn greenish brown, or reddish brown. Since the distribution is a closed system you will have the same water going round and round inside the pipes, picking up whatever is on their inside surface. In the case of galvanized steel or iron distribution piping, products of corrosion will also get into the water. It doesn't necessarily mean that the pipes need to be replaced, but when the joint is resealed the interior of the pipe should be examined to determine how advanced the corrosion is. The water would not be toxic, but I wouldn't drink a glass of it. ; )
