Got something in the water!

Tom_133

I installed a Rinnai I-series boiler a few years ago, probably 6 or so. He has had a couple minor issues, like a few circs, and an internal pipe going bad in the boiler. He has been using his fuel company to get the work done. Recently he reached back out to me, and here are a couple pics of the circs internally. What the heck causes this? He may also have onyx tubing in the slab??

Alan (California Radiant) Forbes

That's from oxygen intrusion, either from the Onix tubing or somewhere else.

Onix has an aluminum oxygen barrier, but from what I've heard, oxygen still gets through.

mattmia2

either oxygen ingress through tubing that isn't oxygen barrier or that has an oxygen barrier that has somehow failed or it is leaking somewhere and getting a lot of makeup water that brings oxygen with it.

hot_rod

rust! Caused by sir (oxygen) getting into the system

Is it an open system, combination dhw and heat?

Connected to a fill valve?

Jamie Hall

Well that's a right mess. As has been said, mostly oxygen corrosion. Which is all very fine, but i think you may have a horrible time getting it cleaned up, if you can do it all. Hate to say it, but it may be cheaper to replace it.

hot_rod

The earlier rubber pre Onix, Entran tubes could do that to a system in a years time! The higher the operating temperature the more O2 they suck.

Those sludge, rust deposits are probably everywhere in the system. There are some cleaers specifically for rust deposits, it may take a few treatments and power flushings.

mattmia2

if it is the tubing you can either set it up as a system with no ferrous components, probably using a heat exchanger or you can add inhibitor to it and keep adding inhibitor. as the oxygen scavenger in the inhibitor is consumed you have to add more inhibitor s if you want to keep the system from consuming itself you need to periodically add more inhibitor.

make sure it isn't just leaking first.

Tom_133

Thanks All,

I had that sneaking suspicion. A heat exchanger and a thorough cleaning and oxygen scavenger is my suggestion. We will see what they say!