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Best Boiler Cleaner for My Problem

HomerJSmith
HomerJSmith Member Posts: 1,421
edited November 2020 in Radiant Heating
I have a circa 1996 infloor radiant sys with a Crown cast boiler that I'm working on. The first thing that I notice in walking into the boiler room is the calcium staining of the SuperVent, which was leaking and the staining of the X-tank and other threaded fittings. The second thing that I noticed was the manifold zone controls for the seven manifolds, Honeywell zone valves, 3/4" piping to the manifolds fed by 1-1/4" copper piping from the single pump, Grundfos UP 26-96 BF. This is a big, big time problem when only one zone is calling for heat.

I pulled the stainless inner core of the Supervent out and you couldn't see thru it, it was so compacted with this brown copper colored sludge. I stuck my finger into the SuperVent piping and there was a layer of this sludge on the bottom of the 1-1/4" pipes. I took the Grundfos boiler pump apart and the impeller was plugged with the same sludge. Gasp!

I deduced that this was copper sludge from pipe erosion because of the large pump and small manifold piping. I don't have time to redo the complete sys and will keep the existing boiler until next spring, but I will make changes in the boiler room and replace the manifolds with ones that have flow controls because I don't know what the original installers did in regards to tube layout.

I need to clean this sludge out of the sys, which in your opinion would be the best product to do this? Gratefully submitted, Homer.

Comments

  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,359
    Power flush it. Each loop at a time if you are able to isolate each of the loops at the manifolds. 

    An Alpha 2 or Taco ECM would be the way to go I'd think. Assuming the loops are close in length. Otherwise a pump for each manifold or a means to balance would be best. 

    I'd wager a good variable pump will solve the velocity issues. Put a good magnetic dirt separator ahead of the circulator. 
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • HomerJSmith
    HomerJSmith Member Posts: 1,421
    edited November 2020
    Thanks Solid_Fuel, a single ECM pump would make sense if I were to keep the Honeywell zone valves.

    The manifolds range from 4 to 7 ports, mostly 6 and 7 fed by a 3/4" type M copper. I have no idea what the pressure loss is or the length of the loop for each manifold. If I were to use a single ECM pump, pumping the max of 6-7 gpm thru each zone when fully open that would be 6 gpm X 7 zones or 42 gpm ECM pump.

    My plan is to zone with 7 circulators, Grundfos 15-58 pumps and put a Taco Acu-flo balancing valve on each zone to control the flow thru the 3/4" manifold supply and limit it to no more the 7 gpm. I hope this will prevent any more pipe erosion which would be catastrophic if leaks occur in the walls or ceiling.

    I will flush the sys with my high head-flow pump, then I want to scourer the sys with a good boiler cleaner and flush the sys 2 more times.

    I have never encountered copper sludge like this in all my years.

    I'm open to suggestions.
  • hot_rod
    hot_rod Member Posts: 15,440
    What type of tubing> Rubber hose by chance?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    kcoppZman
  • ttekushan_3
    ttekushan_3 Member Posts: 942
    Rectorseal 8-way, a popular steam boiler water treatment is actually very effective for hot water system cleaning. It comes with instructions for just your application. 
    I’ve used it a couple times on oily hot water heating systems with success. 

    Prepare yourself for what comes out! 

    The question will be whether you choose to leave a certain therapeutic amount in there as a long term treatment. While normal with steam, I didn’t do that with the hot water systems. Just flushed it out. 

    The cause for your current problem? It looks like you’re addressing that. 
    terry
    SuperTech
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,212
    42 GPM? Sounds like a lot. What size boiler do you have? You can't put 42 gpm through 1 1/4 tubing.

    Tell me what I am missing?
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,359
    Consider that each radiant loop isnt anywhere close to 1 gpm. Generally 0.5-0.75. So the 3/4 copper to each manifold is well within the acceptable flow range. 
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • HomerJSmith
    HomerJSmith Member Posts: 1,421
    hot_rod, it isn't Entran. It is Wirsbo 1/2" hePex with Wirsbo manifolds which I will plan to replace with Caleffi one at a time as time affords.

    I was planning on 1 gpm per loop, but .5 to.75 gpm seems more realistic. 1-1/4" supply header will provide 20 gpm at 4+ ft/sec and I thought that I could demand that off as not all zones would be operating at the same time. The bottom flr is open to the upper flr allowing the hot air to rise which would lessen the upper flr demand. Occasionally, we do get 10 deg below weather, so it is possible that all the zones maybe operating at the same time. I'm limited as to the supply water temperature because the upper flr has plank flooring and the sys has a single supply water temp. The carpet is being replace and I told the owner to choose a low R pad and carpet.

    I will do a whole house heat loss calc and plan on replacing the existing boiler with a mod-con in the spring. The heat emitter is fixed and hopefully they will supply the btu's to over come the house heat loss at the supply temp and the new boiler will be adequate to the task of getting the btu's to the heat emitters.

    Oh, boy, first I have to clean the sys and pray that the pipe erosion isn't so great that pin hole leaks occur. I have never seen a build up of copper sludge like this and it is all coming from the piping.

    Ed, you're not missing anything.

    The sys is down, so I don't know how it previously operated.
  • hot_rod
    hot_rod Member Posts: 15,440
    Seems odd that a good pex system would be so sludged up? Brown color indicates the ferrous metal components are being dissolved. If so, somehow, somewhere you must be getting air (O2) into the system, frequently.

    In a tight, sealed oxygen barrier tube system, the fluid should stay healthy.
    I'd also look for a small leak causing fill water to be added. That might also explain calcium build up.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    kcoppSuperTech
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,560
    Were there any repairs made with NON- O2 barrier tubing, or did one of the originally installed tubes come from the wrong shelf at the supply house? Look at all the tubing that is accessible and see if they are all the same.

    Just a thought from outside of the box
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    kcopp
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,560
    Your title Best Boiler Cleaner for My Problem, made me remember this little Italian guy that worked for my father, He was the best boiler cleaner I ever knew. he could do 6 or 7 boilers a day and all the customers loved him.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    offdutytech
  • HomerJSmith
    HomerJSmith Member Posts: 1,421
    hot_rod, the sludge is non-magnetic, so definitely not ferrous. I am 99% sure it is copper and the dang stuff is tenacious where it sticks. I had to sand blast the SuperVent element to clean it and the impeller on the boiler pump took days of soaking and brushing to remove the grime. When I stuck my finger into the SuperVent 1-1/4" pipe, it felt like a 1/8" of muck on the bottom of the pipes and my finger was stained a reddish brown sludge.

    All the pex is the same, Wirsbo "hePex not for potable water". I haven't call Uponor, but I think it has an O2 barrier as the amount of magnetite that came out of the cast boiler when I drained it down was very little and the volute of the boiler pump showed no real corrosion. No leaking that I can discern except the failed SuperVent, a ball valve stem seal, and a threaded fitting.

    Ed, where is that little Italian boiler guy when I need him?

    Yesterday, I made the necessary repairs, but not all the changes that I plan for, because the owner wanted heat because snow is expected today and this weekend. I decided to use Rectorseal 8 way boiler cleaner, my first time with that product. I will flush the sys next week and add more boiler cleaner and flush it again. Then the real work will begin. Thanks, all.
    EdTheHeaterMan
  • kcopp
    kcopp Member Posts: 3,900
    Was there glycol in the system or did it ever have glycol in the system?
    Do you have pix?
    Did you save a water sample in the system to have it analyzed?
  • HomerJSmith
    HomerJSmith Member Posts: 1,421
    No anti-freeze in the sys, I tested for it. I didn't need the water in the sys tested. Sticking my finger into the 1-1/4" supply piping and coming out with a thick layer of copper sludge on my finger tells the tale. Pic not required. I already repaired enough of the sys to get heat into the structure. I will flush the sys several times and then correct the velocity problems that created the pipe erosion in the first place. Thanks for asking.
  • Zman
    Zman Member Posts: 7,139
    In theory it sounds like a velocity problem. In reality, it is really hard to overpump radiant loops. The curve just gets so steep.
    Anytime I have seen that kind of velocity issue in type M copper, it has pinholes like crazy.

    I think that there was likely a leak that went unnoticed for years sometime in the life of the system. If you give it a good flush (or 10) and install and maintain a good mag/dirt separator, I bet it turns around.

    Are you able to drain the boiler or is it sludged up?
    What is the tap water quality like?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Zman
    Zman Member Posts: 7,139
    Unless someone had a bigger circ in there at some point, I don't see that the 26-96 is causing velocity erosion on it's own. It is possible that the abrasive/aggressive water combined with intermittant high velocity is causing issues but... "Where are the leaks".

    If I were replacing the boiler and getting rid of the mess that it is certainly plugged up with, I would go with zone valves and https://www.supplyhouse.com/Taco-VR3452-HB1-FC1A00-Viridian-Self-Adjusting-High-Efficiency-Wet-Rotor-Circulator-Less-Flanges-Rotated-230V.

    Given that you will have difficulty getting completely clean with out a boiler replacement and your zone lengths are unknown, your zone pump approach seams reasonable enough.

    I would not refill with tap water until I tested it. I still contend that a long term leak being auto refilled with tap water is the cause of all of this. I distilled a perfect corrosion cocktail over years of neglect.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • HomerJSmith
    HomerJSmith Member Posts: 1,421
    edited November 2020
    Zman, just a follow up on your post.

    I never use street water only conditioned water.

    The leak is from a 1-1/4" ball valve over the boiler pump, the cap float on a SuperVent, and a Tekmar 4 way mixing valve stem seals. I plan on using the 4 way mixing valve until I replace the boiler with a mod-con in the Spring as I would have no temperature control without it.

    I already ordered the repair parts and have install some.

    The price would probably even out with a single ECM pump and new zone valves over separate zone pumps and a pump controller.

    It's definitely copper sludge and the only place it could come from is the copper pipes.

    Zman, I really appreciate your input. Thanks
  • EzzyT
    EzzyT Member Posts: 1,185
    I’ve used many different manufacturers system cleaners and inhibitors over the years and I’ve found that Fernox DS 40 has worked best for a lot of the old systems we’ve work on that have been in good overall shape. I would not use it on any system that has had leaks over the years since it’s a very concentrated discale cleaner. Along with the Fernox DS40 we use Fernox F3 and F5 cleaners with a serious powerflushing with our flush carts that have magnetic and sediment filters to insure we get everything out of the system.