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Boiler heat exchanger cleaner

Simply RadSimply Rad Posts: 145Member
I am now starting the see effects of Colorado LP (supposidly the dirtiest in the nation) on condensing boilers. My oldest condensing boiler are now 18 yrs old. Some customers do service and others don't. I have been using CitriSurf 3050 as advised by Viessmann. Today I worked on a Vitodens boiler I install 12 yrs ago which has been fully service by me 4 times. I had a very hard time cleaning the gaps of the HX in order for the condensate to drain. I left the CitriSurf in the HX and went to lunch. Before lunch it was pretty plugged along the bottom. After I, I have able to loosen and clean out about have the gaps. I drained OK. I am wondering what else I could be using as a cleaner on these older,less services boilers. I broke an old CC trying to clean the gaps. I spoke with Citrisurf and they said letting it sit in the exchanger for an hour was plenty of time for the cleaner to break down the "Smegma". Any thoughts are appreciated. Jeffrey
Jeffrey Campbell


  • Simply RadSimply Rad Posts: 145Member
    Here is a pic of Citrisurf sitting in bottom of exchanger.....trying to do its thing

    Jeffrey Campbell
  • kcoppkcopp Posts: 3,169Member
    I usually use a spray bottle of Distilled vinegar. That w/ a stiff plastic bristle brush and scotch-brite works fine.
  • JUGHNEJUGHNE Posts: 4,940Member
    I use a credit card, I have modified the corner by notching teeth into it. With some water applied I saw the junk out from between the tubes. This sends it all down the cond drain.

    I get "coffee grounds" in both Munchken and Lochinvar.
    On these water tube boilers there are perhaps 8-12 tie rods you don't see but can feel them with the card. You can feel the flat bottom and the curve on the arch of the HXG housing. So you know then those areas are clear.
    I stick in 2 cards to protect the back target wall from water if it is not removed.

    Then maybe some CLR cleaner but the coils still look bad after a few years. Those spots don't come off for me.
  • Simply RadSimply Rad Posts: 145Member
    Jughne, I broken aan old ski pass(size of credit card) pass i use as a cleaning tool. I have cleaned lots of boiler and this is one of the tougher ones. Understand lots of these boilers are on LP and 10 plus years old. Trying to figure out a "deep clean" As you saw in the pics the boiler wasn't draining very well to the condensate drain. Kcopp I used a nylon brush and old ski pass. I live in a ski pass reminds me of better days of skiing when I am working
    Jeffrey Campbell
  • nicholas bonham-carternicholas bonham-carter Posts: 7,512Member
    Too bad the design of the boiler does not allow you to (easily/quickly) disconnect and remove the heat exchanger, and soak it in a bucket of acid for the hour.—NBC
  • STEVEusaPASTEVEusaPA Posts: 2,315Member
    I'd show that to the H/O, and explain to them why they need an annual cleaning, or they may end up needing a new boiler.
  • CanuckerCanucker Posts: 472Member
    @STEVEusaPA has a good idea. You may be one of the few techs in the area doing a proper service, they may wonder why you're down there so long compared to others. You should show them why
    You can have it good, fast or cheap. Pick two
  • Simply RadSimply Rad Posts: 145Member
    Oh I did show them. I am hoping to find a cleaning solution though because this is part of condensing boilers we are all going to learn the hard way. SOme of my clients do a great job of maintenance others not so much. I have had an idea of performing a "deep cleaning" in the summer. Cap off the condensate drain and filling the HX will cleaner and leaving it overnite and then flush it the next day.
    Jeffrey Campbell
  • PumpguyPumpguy Posts: 332Member
    edited April 5
    You might want to check out a product called Rydlyme, available from Apex Engineering Products in Aurora, IL.

    Website: <>.

    Phone: 1-800 451 6291.

    I have no experience with this product used for your application, although we used it for years to descale the interior of liquid ring vacuum pumps. I would suggest you contact them first to get their recommendations.
    Specializing in vacuum pumps for steam heating systems, especially older Nash Jennings units. We build new ones too!

    Now offering Tunstall air vent valves for steam and hot water hydronic heating systems.

    Please visit our website for more information
  • HomerJSmithHomerJSmith Posts: 477Member
    edited April 5
    Rydlyme is recommended by HTP as a cleaning solution. I have used CLR but I do use Simple Green Lime Remover. I use a lot of remover and spray it in with a garden sprayer bottle.

    A simple nylon brush is not going to remove that scale and deposits in the picture. I use a 1 1/2" stainless wire wheel on a Dremel tool and a feeler gauge for the slits. I always remove the refractory.

    I make sure I flush it good with water until the trap runs free.

    Works for me. Looks like you may have a combustion setup problem?

    Here's a Munchkin I just cleaned after 4yrs.

  • MikeGMikeG Posts: 150Member
    Homer do you remove the target wall refractory and replace it at each cleaning on the Munchkin? Have you had issues removing the hex screw on the target wall refractory? I've had one I could not get out. Refractory looked OK so I kept it dry while cleaning but not as easy to clean with it in. Just looking for a technique to get that hex screw out. Thanks
  • HomerJSmithHomerJSmith Posts: 477Member
    edited April 6
    I have had that problem. I put a socket on it with a long extension and wiggle it gently. I don't want to break the stud off the separation back plate. I put silicone grease on the threads when I replace it. I do remove it, but it's your call. Refractories are expensive. I don't want to replace it, if I damage it, if possible. The newer refractories are more substantial. I always wear rubber gloves and a respirator when I handle a refractory. The picture is the original refractory.

    Weller/Ungar soldering puts out a anti-seize for soldering irons and tips. I have not used it for that nut, but I think it would work. It sure works for my soldering irons.
  • SuperTechSuperTech Posts: 468Member
    I have used the credit card trick effectively on Giannonni heat exchangers with CLR and an old toilet cleaning brush. Works good to clean up the fire side of the heat exchanger.
    For the water side I like to use white vinegar.
  • Steve MinnichSteve Minnich Posts: 2,121Member
    edited April 6

    Instead of using a credit card, I use those foil duct tape spreaders/smoothers that Polyken and Nashua offer. A picture would probably help.
    Steve Minnich
  • Mark EathertonMark Eatherton Posts: 5,840Member
    Jefferey, how about using a Teledyne Water-Pik? Hydro blaster near ultrasonic.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • bulldoglaxbulldoglax Posts: 37Member
    Viesssmann makes a specific tool for their heat exchangers. We have had good luck with them. A little pricey but comes with replacement blades.

    Item Description:
  • keyotekeyote Posts: 659Member
    Id be curious what a proper annual costs out west because though Im doing them myself if i had understood here in the east a grand a year in maintenance i might have rethought the alleged efficiency of a modcon.
  • psb75psb75 Posts: 59Member
    We don't discuss pricing on this forum.
  • keyotekeyote Posts: 659Member
    Im aware of that policy,I didnt mean your specific price nor would it be a quote to me as i said im across the country only a general number useful for honestly evaluating the alleged efficiency of mod cons. Maybe Im wrong but i dont think heating helps policy proscribes a comment like "True mod con cost calculation has to take into consideration the need for an annual dismantling to clean the HX ignitors etc most manufacturers recommend at that time other diagnostic work be done. since the tear down can often cause the need for expensive new gaskets or other parts that can go decades without needing replacement on traditional boilers, and because the technology is beyond the average plumbers experience youre going to be relying on a plumber that has a virtual monopoly on your brand boilers service contracts in your areas, and while its a well known fact that large mechanical companies actually do installations on large construction projects at cost in return for lucrative service contracts this is not a model the average homeowner is really bargaining for when they are considering the benefits of modcons. its fair to say you should add $$$$ to your annual calculation against any fuel savings.
    Im in the business airside on large commercial jobs and work hand in hand with steam fitters on the water side sometimes entirely without them on certain types of systems. Im comfortable tearing the unit down doing the combustion analysis and a gas reading with a manometer. but not owning the equipment i wa forced to try to find a plumber. heres what happened the first three licensed plumber one with a fleet of vans all looked at me like i was speaking greek when i ask if they could do a combustion analysis, the manufacturer recommended a guy who wanted - lets say he wanted more than the cost of an entry level analyzer just for the analysis and would not give an estimate for an annual even when i told him I had all the spare gaskets ignitors ets on hand. without getting into pricing or why a modcon a year old that was tuned to factory specs at commision should need to be reanalyzed and admitting Im not actually a "plumber though I braze HVAC pipes all day at work when im not in MEP coordination meetings or directing cranes to drop million dollar cooling towers on dunnage i welded up. and admitting im earned the nickname micrometer mike if i were a plumber doing a service knowing what i now know about modcons i would include the fuel and combustion analysis on any boiler i was servicing it takes a few minutes. but what the average homeowner is looking at is paying about 10-20% of the cost of the boiler annually. I get we are skilled mechanics and should make at least a white collar wage in big cities thats way into six figures. But homeowners need to be able to make informed decisions, if mod con manufacturers cant make maintenance free boilers they need to be upfront about the actual costs particularly since their main and really only selling point is the increased efficiency, as it stands what they are actually selling is a vanity product for green holiness signaling like solar panels that make no sense economically but make you feel good about your puritanical carbon free life
  • SuperJSuperJ Posts: 306Member
    keyote said:

    Id be curious what a proper annual costs out west because though Im doing them myself if i had understood here in the east a grand a year in maintenance i might have rethought the alleged efficiency of a modcon.

    Well, we don't discuss prices, but I think it fair to acknowledge the maintenance costs with respect to making an informed decision.
    There are a lot of factors for modcon maintenance, but I think the elephant is water quality, which is pretty straightforward to deal with. Most people don't pay enough attention to water quality. Better to pay upfront for proper water treatment (and ongoing MU water treatment), than out the nose when you ignore a modcon on bad water and spend $$$ descaling or toast the HX.

    Personnally I like the idea of high mass boiler for high efficiency, single pump simplicity, no min flow and lower maintainence.
    Think HTP Pioneer, or Viessmann Vitocrossal CU3A.
  • keyotekeyote Posts: 659Member
    Yes water and gas quality is the culprit in NYC we have excellent water and gas and so i wasn't concerned Lochinvar however used it as an excuse to stall my complaints about their malfunctioning boiler by insisting I needed to do my annual, i knew perfectly well this wasnt true but had to do it to eliminate this it didnt help as they have a very long list of why nothing is ever their fault so if i were not in the business i would now have doubled the cost of 5k for their boiler in troubleshooting labor. That said I dont think the average homeowner is capable of really knowing how often they need to tear down their machine in fact id bet a weeks pay very few have any idea they are ever expected to pay someone to tear apart their machine
  • Simply RadSimply Rad Posts: 145Member
    Homer J....Do you know that one should never use a metal component to clean a stainless steel HX. The HX is coated with a protective coating that is very sensitive to metals. Every mod/con manual I have read says only to use a nylon brush and cleaner. You picture looks good but I am sure you are compromising the HX. Also, understand these boilers are 10-15 yrs old and this has happened over a long time. I am not sure of LP outside of Colorado but all my units are generally very dirty with LP. I pride myself on setting up each unit with a combustion analyzer for the best combustion. I have been to many Viessmann boiler trainings and they all say that Colorado has the dirtiest LP in the nation?
    Anyways, I find over time the LP contanaments bond to them selves the HX. The Credit Card I use is a VIsa so its gotta be strong, since it put me in all this debt :-) Anyways its very bonded to the HX and a hand tool alone is not the answer. ME, I like the idea of the Ultra Sonic, the water pik is a little weak.
    I really think capping the condensate drain and filling the combustion chamber with the cleaning agent over night may help. Unfortuneatly, we are still in the heating season so I will have to wait a bit longer to try this.
    Jeffrey Campbell
  • HomerJSmithHomerJSmith Posts: 477Member
    edited April 13
    Simply Rad--I'll investigate your coating statement further. I do want to clean an HX correctly.

    As, I recall HTP said to clean the HX with a brass or nylon brush but not with a steel brush. I have used a combination of nylon and stainless steel with products like Rydlyme and CLR. Stainless steel is a different composition than steel. No reason was given in class for not using steel and I was too dumb to ask.

    What is the nature of this coating? How does this coating fair in a hot combustion chamber? I guess phosphoric acid isn't detrimental to the stainless HX coating. Why does Viesssmann have what appears to be a metal tool (as stated above) to clean between the stainless tubes? How does that effect the coating?

    I haven't come across any, from an engineering point of view, research on the cause of the coffee grounds, staining, and the nature of the deposits on a used HX. I know that the coffee grounds are magnetic because I tested them. We know that zinc ions can migrate out of brass, over time, and weaken the copper alloy. Is this what is happening to the stainless HX with the coffee grounds?

    We know that CI boilers can last upwards of 40 yrs. How long of a life span can we expect out of a stainless HX, assuming setup, water quality, and maintenance are all done correctly?

    I had a friend that was doing stainless steel kitchen fabrication. When he finished welding the stainless, he would use a low voltage transformer with a rag on the end of the probe with phosphoric acid and remove the heat discoloration from the stainless welds. This is why Viesssmann recommend using phosphoric acid to remove the staining on their HXs?

    The Viessmann cleaning filler is suitable for Viessmann Vitodensanlagen and is used to remove Incrustations or other impurities in the combustion chamber.
    Scope of supply:
    2 x replacement blades
    1 x cleaning spatula
    Material Stainless Steel

  • HomerJSmithHomerJSmith Posts: 477Member
    edited April 14
    And what does bad propane mean? Too much butane or other gasses, maybe loose (unbonded) carbon chains?

    I had a friend tell me about a TT fire tube boiler running on propane that he worked on. He said that the tubes were all "gummed up" (his words). My assumption was bad combustion setup, incomplete combustion, and a dearth of free air.

    When we do a combustion analysis, it's snapshot of combustion at a specific point in the combustion-boiler operation. The combustion stoichiometric changes from boiler startup to shut down. A combustion analysis is done at a point of the greatest stoichiometric consistency in the boiler cycle.

    That's my story and I'm sticking with it.
  • CanuckerCanucker Posts: 472Member
    edited April 14
    @HomerJSmith it's called passivation. When you use regular steel tools to scrape the surface of the stainless steel, it can remove the protective layer that naturally forms. When that happens your stainless steel starts to rust. We use oakite 33 for the surface preparation after any welding or grinding
    You can have it good, fast or cheap. Pick two
  • hot rod_7hot rod_7 Posts: 9,030Member
    Maybe this brand? They have a fire side and water side cleaner

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • HomerJSmithHomerJSmith Posts: 477Member
    edited April 15
    Oakite 33
    Rust, oil and scale remover, phosphoric acid based. "Oakite 33 is a liquid, acidic compound used for removing light grease, oils, shop dirt, flux, rust, oxides, scale on steel, stainless steel and aluminum." It doesn't say that it adds an oxidizing layer to stainless steel.

    I'm aware of "passivation", most commonly with aluminum as aluminum oxide coating that normally forms on exposed aluminum. Rust is the most common form most people come in contact with as it it so readily visible.

    This is a process of 'Reduction', Redox, where nature tries to return everything to its elemental stable state. Not only is oxygen an oxidizer, there are many others such as chlorine, which is detrimental to stainless steel.

    "Stainless steels are corrosion-resistant by nature, which might suggest that passivating them would be unnecessary. However, stainless steels are not completely impervious to rusting. One common mode of corrosion in corrosion-resistant steels is when small spots on the surface begin to rust because grain boundaries or embedded bits of foreign matter (such as grinding swarf) allow water molecules to oxidize some of the iron in those spots despite the alloying chromium."--Wikipedia. (Is the last sentence why the use of steel brushes are not recommended for cleaning the HX?) Do steel brushes leaves minute traces of iron (exogenous iron) behind to oxidize?

    This is what I have long suspected, that the coffee grounds are Magnetite, Hematite, or possibly Greigite , or a combination of all three. The presence of coffee grounds is an indication, I think, of a degrading HX. It is a 'rusting' out of the iron in the stainless steel. How pernicious it is, I don't know. How it effects the longevity of the HX, I don't know

    I'm not aware of any anodizing processes used with stainless HX's to limit oxidation which could be removed by aggressive cleaning. Any "passivation" of the stainless steel is a naturally reoccurring process, such as the tarnish on silver, I would think, and any oxidation layer would be minimal.

    Thanks, 'hot rod', I think I will give axi-therm a try, altho I would like to see an ingredient list (MSDS).

  • JUGHNEJUGHNE Posts: 4,940Member
    If the coffee grounds are the iron coming out of the SS tubing, then considering that it is common to find perhaps 2 tablespoons of "grounds" (which will stick to a magnet) every 2 years in the bottom of the water tube HXC, it seems the tubing should have a pretty short life. Also consider the "grounds" that were washed away by the condensate that we do not see.

    I service a 15 year old Munchkin that will produce enough grounds to require cleaning at least every 2 years. 3 years is too long.
  • hot rod_7hot rod_7 Posts: 9,030Member
    I wonder if anyone has had the "coffee grounds" analyzed?
    I always thought they were a combination of the intake air and contaminants along with byproducts of combustion.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • JUGHNEJUGHNE Posts: 4,940Member
    I think that is the general consensus. IMO, I want to add in the use of PVC with the condensate washing something out of the pipe and than draining back into the HXC............

    But the ferric properties of being attracted to the magnet?
    The only Iron element would be in the SS HXC.
  • HomerJSmithHomerJSmith Posts: 477Member
    I'm sure that a "...combination of the intake air and contaminants along with byproducts of combustion..." are part of the problem with coffee grounds.

    The 2 tablespoons full of coffee grounds are not wholly iron products, I think, but, a small percentage of the coffee grounds are iron mixed with combustion byproducts, combustion byproducts being the major component. It would still be magnetic.
  • ced48ced48 Posts: 429Member
    Just cleaned a Lochinvar WH55, 5 years in service, running on Rhode Island propane. Total waste of time, nothing to clean.
  • hot rod_7hot rod_7 Posts: 9,030Member
    only a few grades of stainless stick to magnet, I didn’t think the 300 grades did? Where else would ferrous components be in the hx combustion side?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Simply RadSimply Rad Posts: 145Member
    So here is a pic from a few years ago of a Vitodens 200 boiler on LP. I believe it was 3 yrs since the last servicing. There are ALOT of coffee ground in this one. But as you can see with the after photo it cleaned up pretty good. One major factor about my location is Steamboat Springs sits at 7000' with home sits up to 8800'. I have spend alot of time with Viessmann tech support figuring out how to set up these boilers with the best combustion. So one thing to add to the topic is the fact that this boiler does not use PVC venting,(Viessmann does not allow PVC vent) and instead is using Polypropylene. I think the coffee grounds are sololy the results of burning fossil fuels.
    Jeffrey Campbell
  • CaptainCaptain Posts: 25Member
    Axiom's AXI-Therm combustion side cleaner works well. There are a number of manufacturers who approve it for use the their HX's. They have one specifically designed Stainless Steel and Aluminum heat exchangers. Here is a SS HX cleaned with their CLEAN F Steel product.

  • CanuckerCanucker Posts: 472Member
    > @HomerJSmith said:

    > "Stainless steels are corrosion-resistant by nature, which might suggest that passivating them would be unnecessary. However, stainless steels are not completely impervious to rusting. One common mode of corrosion in corrosion-resistant steels is when small spots on the surface begin to rust because grain boundaries or embedded bits of foreign matter (such as grinding swarf) allow water molecules to oxidize some of the iron in those spots despite the alloying chromium."--Wikipedia. (Is the last sentence why the use of steel brushes are not recommended for cleaning the HX?) Do steel brushes leaves minute traces of iron (exogenous iron) behind to oxidize?

    That is my layman's understanding of what oakite treats. We use it to treat the stainless steel after welding or grinding. It's been my experience that a really aggressive scrubbing of the surface with steel brushes can cause the surface to rust, in the environment we use it in (Some solutions are quite aggressive) Like you pointed out, it tends to be the welds that end up with corrosion.
    I have a friend who has a master's degree in chemistry, very knowledgeable about this. I'll see if he can confirm how and why the passivation works
    You can have it good, fast or cheap. Pick two
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