How do you clean heating lines?

I just drained my boiler and the water was pretty rusty and brackish. I have a way to hook in a pump to circulate threw my lines in the house. I know they are dirty because the pex lines turned black. I have a combination of pex and copper, fin tubes, wall heaters, and infloor. What kind of cleaner or detergent would you run threw them to clean them. I'm trying to get ahead this year so maybe I will be ready if the temps ever go down. Thanks for the help. Jim

Is the water more black or red?

Black is normal. Red could indicate rust.

I don't have a good answer for you, but I do suggest you find out why your are getting rusty water. After several years my boiler water remains nearly clear.

I once tried to clean dhw steel pipe that did not have good flow. and I first used a detergent, which successfully loosened scale that clogged the pipes up completely. I then tried an acid wash under pressure, which at first seemed to work and then finally plugged the pipes with loosened material that I could not free up. End of story and solution was new plumbing.

I'm with Mike, is it rust or normal closed loop black boiler water? Is this a totally closed system? Or are you talking about the Empyre water?

TS

Black is good, its like fine wine to a hydronic system, no need to clean in my opinion unless you are getting sediment build up, then you need to find out why. I work in the commercial/industrial side of plumbing, all new systems I install are flushed with a TriSodium Phosphate (TSP) solution during commissioning of the system, this is to clean any cutting oils or slag that might be present in the system.

The part I drained was the pressure side. The water was quite rusty. I am pretty sur it came from the 1000 gallon tank. I am replumbing again, removing the storage from the system and going to all non pressure per instructions from Pro Fab. They assured me this will make the system work better. I will eliminate two pumps, a couple of strainers and a heat exchanger. I think I will try to flush the system with TSP. Can you get the real stuff anymore or just the "enviromentally friendly" substitute kind? Thanks for the help. Jim

Does the pex have an O2 barrier?

As far a general cleaning is concerned, a good stiff solution of TSP or a commercially available boiler cleaner such as you would find at a P&H supply house would do the trick. Lot's of different brands.