water in closed system is pretty dirty and rusty despite o2 barrier PEX. Is this normal?

Conifer745

DIYer here. I designed and retrofitted this heating system in my home 2 years ago when I was starting my basement remodel. This is the 2nd season of heating. I'm in a cooler climate out west, so can use heat anytime from October-May typically. The system initially went live with 2 zones - radiant floor zone with 7 circuits for my main floor, and a higher temp panel radiator zone for my top floor. Last summer I added 2 more radiant floor zones (2 circuits each) in my basement. There is probably about 35 gallons of water in the system. The system uses o2 barrier PEX throughout (mostly PEX-b, except for the basement which is PEX-AL-PEX). The boiler is a Noritz combi boiler that also does my DHW.

Last summer when I added the basement zones I noticed that the water was really dirty so I decided to put in a Adey magnetic filter. At that same time I flushed the system with clean water (I didn't put any cleaner in prior to flushing). I recently checked the magnetic filter and again found the water to be really dirty - there were a few tablespoons of metal "mud" that the filter had caught. Is this just normal operation? Is it the result of adding the new zones?

My plan is to put in a cleaner like MC3+ for a few weeks prior to flushing with new water. I'm guessing I also need to add an inhibitor. The water I am putting into the system is my domestic well water post whole-home sediment filter and water softener. Also note, that there was some air in the system as a result of a leak I had to repair after puncturing the PEX during flooring install. That air has since been bled out of my radiators on the top floor. I had a plumber recommend putting in glycol, but general sentiment i've read on here is that's a bad idea.

hot_rod

Hydronic water will never be crystal clear. It will pick up "color" form the metals and fill water.

If you keep draining some sludge or magnetite I would address the fill water and a good hydronic cleaner. Magnetite only happens if a ferrous metal is breaking down, it should not be an ongoing problem.

Check the fill water for hardness, TDS, Ph as per the manufacturers spec.

I'd refill through one of the DI cartridges. Personally I like a squirt of hydronic inhibitor even with DI water. It gives you film providers, Ph buffers, Oxygen scavengers and some lube for the pump bushings.

The hydronic conditioners come with test kits so you can maintain whatever conditioner you may add.

You can send a sample of the current water to Rhomer, Fernox and others for an exact analysis of what is in it.

There are a number of companies that offer fill cartridges. Fernox, Rhomar, Adey and others for cleaners and conditioners.

Larry Weingarten

Hi, I'll add that salt softened water isn't a good thing for your system. I'd flush it out and follow Hot Rod's suggestions 😉

Yours, Larry

Conifer745

https://forum.heatinghelp.com/discussion/comment/1801190#Comment_1801190

Thank you! I think one of those disposable cartridges would work great.

Conifer745

https://forum.heatinghelp.com/discussion/comment/1801192#Comment_1801192

Interesting. I did not know that for the heating system. On the DHW side the install manual specifically called for softened water. I have a hose spigot I installed for my wife's gardening pre-softener, so i'll just use that.