Hi,

I recently drained my friends combi boiler added some sludge remover, then
eventually put some inhibitor into the system, for the first couple of weeks
my friends was really pleased as he noticed that the boiler was quiter,
however he is not noticing that when he puts the hot water on there is brown
water that initailly comes out, he is positive this has only started since
the system was drained.

Any ideas what could possibly be doing this.

BTW, sludge remover and inhibitor fed into the system via radiator.

Regards