water additiives for closed loop system

Unknown

Al

you got that right

Jake

John_54

water additiives for hot water heating system

I have a 50 year old 4 story 24 unit apartment building. Should I be adding anything to the water to protect the pipes (black iron) and/or improving the flow. Most of the rads are working alright. One local plumber told me that its sometimes better not to add anything as it can harm the pipes???

Al Letellier

additives

Don't know your water conditions there, but we have an old saying here...."if it ain't broke, don't fix it". It would be far better to make sure the system is tight and leak free. The less make-up water(oxygen) you have to put in, the better. I can't think of any reason to install additives. Maybe someone else can enlighten me too, but I would leave well enough alone.

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Aidan (UK)

Chemical treatment

John,
You should be adding;

1) a pH adjuster, typically caustic soda, to get the system ph to around 9. A pH of 7 is neutral. Less than 7 is acidic and indicates galvanic corrosion is going on. You can check the pH with litmus paper.

2) An oxygen scavenging chemical, typically sodium sulfite. This will take out any dissolved oxygen before the dissolved oxygen takes the inner surface off your pipes. You should be testing the water regularly to ensure the concentration of the scavenging chemical remains at around 200 ppm (I'm not sure if it's 200 or 400 ppm without looking it up, but I think it's 200).

Neglect of the chemical water treatment is the mother of all false economies. You should be able to find a suitable packaged treatment and test kits for a modest amount. Fernox is the bigggest supplier here, but I don't know what's available to you. Ring around a few treatment companies. Beware of men in suits selling magic potions.

A system can last a lifetime with no treatment, but if there's a problem with oxygen absorption, you need to know.