Electrolysis Problems in a Hydronic Heating System

Don't you mean dielectric corrosion?

Any hydronic heating system will develop corrosion especialy around air vents and pressure regulators and relief valves

I mean electrolysis of dissimilar piping ( copper,brass ,steel, & aluminum)in system.

the cheapest way is to use anticorrosion additives. There are many people selling them. The problem is the need to test and maintain the additive level at a protective level = cost and labour.

If you want trouble free, maintenance free, use the more costly non corroding parts and piping. My more costly, = 3-4 times as expensive to install. Stainless pipe, valves etc. Most people use cast iron and check additives every 3 months by hiring a firm that does this if they do not want to hire the staff to do it.

I read somewere that Sacraficial anodes ( Zinc ) can be used.Will this do the job?

Sacrificial anodes of magnesium are used to protect marine outboard engines operating in salt water.

use di-electric unions or fittings to separate dissimiler metals. These are standard catalog items, available from plumbing or pipe distributors.

G Scott

Extending #4 ......Refering to hydronic systems. These are "closed" systems, where (heated or chillede) water is circulated, not pipeline, transport, systems. Electrolysis is caused by galvanic action, primarily copper or brass and steel piping, that literally eats away the metal. Holes caused by electrolysis result in bright, shiney holes, as opposed to rusty holes caused by corrosion. Corrosion is caused by dissolved oxygen in the water which attacks the pipe material, such as steel pipe. Condensate return piping in steam systems are notorious for corrosion, because of the air that enters the system.

gs

Cost effective Sacraficial less noble materials like magnesium prevent galvanic corrosion between dissimiliar or more noble materials. Cal rods were used to successfully to protect hot water tanks from galvanic corrosion. The throw away society sacrafices the tank material or lines the tank with a bladder or glass. Pipelines use sacraficial magnesium blocks strategically spaced and attacked along the pipe, periodically checked and routinely replaced. According to recent reports, the Alaskan pipe line neglected the protection.

In addition to sacrifice anodes to protect the material, you can also use electric current to protect your material, inverting the normal flow of current that causes the galvanic corrosion. Then, replace the sacrifice anode regularly.