radiant chemical treatment recomendations

mburg

I installed a new boiler on a radiant system originally installed 20 years ago. the system had onix tubing. I here that this tubing did not have an oxygen barrier. I have issues with sludge formation my dirt separator completely plugs up every year and each radiant loop has to be purged or flow is cut down to almost nothing. since replacing the tubing is not an option what can I do to help keep the system clean. is there a chemical treatment that will put a oxygen barrier on the tubing? Any recommendations for water treatment to make the system manageable would be greatly appreciated. I have no experience with using any chemical treatment witch makes me hesitant but I feel this job may require it.

Jamie Hall

There are oxygen scavengers available. This website: http://www.accepta.com/water-treatment-chemicals-wastewater-effluent-treatment-products/boiler-water-treatment-chemicals/oxygen-scavengers-boiler-water-treatment-chemicals
has comments on some of them. Most of them are not nice to work with -- do use an RPZ backflow preventer if there is any possible connection to domestic water -- but they do work and might help. That's not the only website, though -- google "oxygen scavenger" for more!

hot_rod

First a good cleaning with a hydronic detergent like Rhomar or Fernox. Then assure the system holds pressure and is leak free, it may have a small leak and be taking on water and minerals?

Next fill it with low TDS water, add a conditioner from the above companies.

I would suggest a fill tank instead connection to potable water. This allows you to monitor for leaks, and also allow you to boost the inhibitors every few years. This also eliminates the problematic back flow preventer.

IF the tube does in fact say Onix it was the tube with an O2 barrier. The name Onix came from "nix the O2" There was an early version that was orange colored like the Entrans.

It's debatable how well the early versions of that O2 barrier work, it went through several stages to get to the current model with an aluminum wrap.

If you have frequent sludge either O2 ingress or frequent fill water is entering. Also the higher the operating temperature the higher the rate of O2 ingress. Outdoor reset controls help minimize high temperature operation.

Check your potable water with a TDS meter if possible. If it is below 100 ppm, you could use it fill. If not run it through a demineralized.

SWEI

Does the new boiler (or any of the other system components) have steel or iron in it?

mburg

the boiler is stainless, iron pumps and steel llh. All the rest is copper brass or tubing.

kcopp

I have had good luck w/ Onix being treated w/ Rohmar and Fernox.
flush out the system , add the cleaner, leave in for 1 week and run the system a lot. Flush it out and depending on how that looks hit it again w/ the cleaner and/or add the inhibitor. After that test for the amount in the system.
Fernox has a test kit in their commissioning kit.