HOT WATER CONTAMI NATION

[GeoffC]

My domestic hot water appears to be contaminated i.e. it is of light black colour, usually worse when first turning on the tap (in the bathroom say) but never goes completly clear even after running the water for a while. I believe I have a Primatic water tank (there is only one cold water storage tank, there is no expansion tank). There is a(sprung?)valve in the main hot water pipe emerging from the top of the boiler, which seems to have a slow leak and is somewhat encrusted - could this be the problem, or part of the problem?

Also, I notice whenever I take off a radiator(while decorating)it contains a fair amount of black sludge - can it be that my hot water is being contaminated by by central heating system? Hope someone can help

 

[oilman]

I would replace the primatic with a conventional cylinder and add a feed and expansion tank. You are obviously getting the heating and tap water mixing. While it may be possible to fix it without changing the cylinder, you cannot use corrosion inhibitor in the system with a primatic, so your radiators will continue corroding.