heating

There is oxygen in the water. Fish breathe oxygen through their gills and spit tiny gas bubbles. A hot water system (hydronic) was drained to replace a portion of the pipe and it is now ready to reintroduce fresh water. All radiator valves are closed and water is reintroduced into the pipes, radiators, controls and safety in the boiler. As the pressure increases in the system, it eliminates the excess air by slowly opening purge vents on each radiator until water comes. When there is more air in the system, you can run the burner. Then the water heater to the desired temperature.
What does it with oxygen that is in the pipeline? In fact, whenever the hot water passes through the furnace, a few air bubbles escape. The air is lighter than water and therefore rises as high as possible. It is for this reason that we can purge the radiators, each year before starting to heat up and this long after the system was emptied and refilled.
One wonders why a galvanized metal pipe providing potable water suffers from erosion after about forty years and a metal not covered in a heating system hot water can last more than a life without rust. The answer: the scientific term for rust, oxidation and it occurs only the presence of oxygen. In theory, if we could totally eliminate the air in the heating pipes and never have to add water, piping and accessories we could survive.
Here are some "pipes" which would do well to remember about hot water heating:a) When you bleed the radiators, try to close the valve just before water appears. There is a pressure valve called 'heat control' (sometimes called Mueller), usually attached to the ceiling above the furnace and adding water gradually as it evaporates and it reached up to the desired pressure. Remember that cold water contains oxygen and if it drains water from a heating coil, it will be reintroduced, thus lengthen the duration of the expulsion of air.b) If there is water flowing from a safety valve, it may be defective or it is simply his work by relieving excess pressure. We must remedy this situation immediately to "relieve" the work of the furnace and for there to be the least of water escaping. c) While the air is lighter than water, an accumulation of air at height can prevent or block the flow of hot water. Do not at any time the furnace does not overheat. When it comes to a hydronic heating system, air is the enemy number one.