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color of water at manifolds

We switched to a Rinnai boiler 3 years ago and changed from glycol to water since we now have a generator to handle power failures when required. Zurn designed our system when we originally put it in 2000.
All Taco pumps are bronze. Can't figure out why the water in the lines actually looks so dark I can't see the spring to adjust flow rates in the manifolds...it looks disgusting. I'm flushing the system today but would appreciate input on what caused it and how I can prevent it.
Please advise.
Thanks so much.


  • hot_rod
    hot_rod Member Posts: 22,118
    Any steel or cast iron components? Expansion tank, steel pipe nipples, cast air scoop? Most any ferrous metal will cause the water to take on a tint.
    Even glycol systems with brightly colored fluid tend to go grey after time.
    I always recommend running a hydronic cleaner first, basically a formulated detergent. That will take out some of the assembly products, flux cutting oil, grease, dirt,etc.
    It's virtually impossible to keep the water or fluid clean and clear.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • cricket
    cricket Member Posts: 3
    All components copper or brass...Rinnai ss.
    Never had an issue until we put in the new boiler. How do I get the "hydronic cleaner"? I'm quite rural and access to hydronic needs are online or what I can find at the local lumber yard...thanks for your response.
    We installed boiler, fill valves, etc w/help of SupplyHouse in 2017...we were supposed to be able to fill the system from our mechanical area but my husband (GC/Architect) didn't think we had to open the flow lines at each manifold and work on each zone separately to flush...I'm a bit old school (coached by a Dad who was HVAC w/Johnson Control)...and thought the manifold adjusting screws needed to be opened to clean it up the fluid. He's also cut into the system this week to add a radiant heated indoor resistance pool that's still in process...so we've been sweating pipe recently also.
    Your help/input is SO appreciated since currently subs just don't even call you back.
  • cricket
    cricket Member Posts: 3
    is this the kind of discoloration? seems severe but I'm trying to get the system back up and running.