Watering up My New Stoker?

Ok, coaledsweat, I understand what you were getting at, the difference between the bubbles of air in the system, and the molecular-level oxygen.

I wasn't thinking of Pex in the system, with an iron pipe system, or copper pipe, or a combination of both, once the bubbles and disolved oxygen are purged, the water should have a lot less oxygen in it to cause any corrosion.

I was under the impression that the early pex systems, and early burried pipe systems that did not have any oxygen barrier were not prone to oxygen migration through the tubing if the water inside was under pressure, apparently this is not correct.. .

Well, from my point of view, I'd still want to take my boiler and system for about a week-long 'test drive'. Look for leaks, listen for noises, trapped air bubbles, noisy pumps.. noisy fans and stoker motors etc.. otherwise you have an unopened wrapped 'gift' waiting for the 'surprise' next fall. I'd prefer to 'test drive' and then know I have to only light the fire next October.

Greg L

coaledsweat wrote:When you radiant floor heat, the water temp is reduced from what the boiler operates at to a level much lower. If this makes no sense, tell me why a pressurized Pex systems need a plastic tube with an oxygen barrier. It doesn't leak water under pressure, how can oxygen get into it? The water is laying inside that Pex with a Victoria's Secret outfit on calling the oxygen. Without that barrier, there will be an orgy. The water will not turn up with a lot of air bubbles, it will have molecular oxygen entrained and that will cause rust.

The oxygen molecule makes it's way through the pex tubing by the osmosis process. See: (https://en.wikipedia.org/wiki/Osmosis) for an explanation of the osmosis process. The aluminum barrier in PEX-AL-PEX tubing stops the oxygen migration because the aluminum molecules are closer together than the size of the oxygen molecules and they can't get through. The PEX tubing that has an "oxygen barrier" only, i.e. no AL, does so with a coating that has a molecular spacing smaller than the oxygen molecule. The problem is the thin coating is on the outside of the tubing and gets rubbed off during installation.

Yanche wrote:The oxygen molecule makes it's way through the pex tubing by the osmosis process. See: (https://en.wikipedia.org/wiki/Osmosis) for an explanation of the osmosis process. The aluminum barrier in PEX-AL-PEX tubing stops the oxygen migration because the aluminum molecules are closer together than the size of the oxygen molecules and they can't get through. The PEX tubing that has an "oxygen barrier" only, i.e. no AL, does so with a coating that has a molecular spacing smaller than the oxygen molecule. The problem is the thin coating is on the outside of the tubing and gets rubbed off during installation.

Bingo! That is the first half (I knew you would know ). Why does the water stay inside the tube even though it is under pressure and smaller than the oxygen molecule that gets in?