Builders have renewed all the plumbing and electrics in our house: new copper piping, new radiators, new underfloor heating, new Vaillant boiler, new Megaflow. When the plumbers removed two radiators in different rooms so that carpeting could be put down, thick brown sludge poured out of the radiators (made by Bisque). The plumbers claimed to have flushed the system all the way through the building work and can't understand what has happened.
Am I right to expect the water in the system to be crystal clear and not brown? How can oxidisation happen so quickly ?
A mate of mine who is an experienced big company contractor director says it can only have happened because the plumber didn't take enough professional care in tightening pipe connections (the five-turn method), and air has entered the system.
Is he right? Has anyone come across anything like this with all-new equipment, please?