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Thread: Damage to heat exchanger... rescue?

  1. #1
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    Aug 2016
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    Damage to heat exchanger... rescue?

    well, a couple of brazetek heat exchangers in the brewery were looped into a passivation cycle using a strong acid#5 solution. the tanks and all the stainless were left to dry and they're fine, mission accomplished there.

    unfortunately the hx's were not rinsed and some blue/green stuff (oxidized copper, looks like) and rusty colored material formed in the bottom outlets, where a bit of solution puddled and stayed. quite a bit of rusty/red powder came out when flushed. manufacturer instructions for these kind of hx's usually tell you to limit sanitizer/acid contact time. bummed that these instructions were not heeded.

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    question is: can these hx's be revived, or are they probably shot? obviously a visual inspection is limited to what a flashlight can see in the four openings, these suckers can't be opened up.

    i ran an normal acid cleaning cycle for kicks, and some rusty powder came out in the cip solution. what the insides look like is god's own mystery.

    anyone have any experience with this kind of thing? (btw, i hope this serves to inform others with these types of hx's to not leave strong acid hanging out too long)

    any help is greatly appreciated. hopefully i won't have to replace them. thanks all...
    Last edited by PWB; 01-08-2018 at 08:22 PM.

  2. #2
    Join Date
    Sep 2005
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    Louisville, KY
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    Worst case you pitted/severely weakened you brazing material. Best case, you cleaned out some buildup. Safely put it under high hot water pressure. If it leaks it is shot. I would also check flow to make sure you get full flow rate. Best of luck.
    Joel Halbleib
    COO / Zymurgist
    Goodwood Brewing Co
    636 East Main St
    Louisville, KY
    goodwood.beer

  3. #3
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    Aug 2016
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    thanks for the input, if this were a non-food grade situation i'd go ahead with the pressure test and such, but from what i saw come out of the chiller i have no confidence with beer involved. got a good response from brazetek. they basically say it's the edges where the copper is that i need to worry about, and since there is no access, they can't guarantee anything, and failure could occur at any time.

    from what i researched, not many acids react strongly with copper. unfortunately acid#5 is 38% nitric acid, which is great at crushing copper. i'll be buying two new hx's and considering myself lucky the cost is relatively low for such a bone headed maneuver. on with the show.

  4. #4
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    Apex NC
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    Out of interest, why are you using those hose disconnects for your chilling water? They seriously choke down the flow rate and resulting chilling capacity of the cooler. You can get cam lock type quick disconnects in 1”, 1.5” varieties which will flow much better from McMaster Carr

    I used to use those hose QDs on my tube-in-tube home brew chiller and once I ditched them I almost halved my chilling time.

  5. #5
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    Oct 2013
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    Dallas, Bangalore and soon Goa
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    Quote Originally Posted by PSkelton View Post
    Out of interest, why are you using those hose disconnects for your chilling water? They seriously choke down the flow rate and resulting chilling capacity of the cooler. You can get cam lock type quick disconnects in 1”, 1.5” varieties which will flow much better from McMaster Carr

    I used to use those hose QDs on my tube-in-tube home brew chiller and once I ditched them I almost halved my chilling time.
    +1

    I always try to let my equipment be the restriction and not the supply or return. You can always throw a properly sized valve in line to reduce flow if needed.

  6. #6
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    Quote Originally Posted by PSkelton View Post
    Out of interest, why are you using those hose disconnects for your chilling water? They seriously choke down the flow rate and resulting chilling capacity of the cooler. You can get cam lock type quick disconnects in 1”, 1.5” varieties which will flow much better from McMaster Carr

    I used to use those hose QDs on my tube-in-tube home brew chiller and once I ditched them I almost halved my chilling time.
    great suggestion. i'll definitely check that out. part of the reason some of my system is frankensteiny is that i'm in rural Panama. getting parts is either catch as catch can or expensive shipping through freight forwarders. mcmaster carr won't deliver to a forwarder in miami, but i'll be visiting my pop soon back stateside and can pick stuff up then.

    thanks!

  7. #7
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    Enterprise, Oregon
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    Any iron or galvanized pipe in your plumbing system will dissolve due to galvanic action, and deposit itself on your copper parts--including the plates inside the HX. I suspect this is where the rusty looking stuff is coming from.

    You may have just doubled or tripled the efficiency of the HX--if you didn't ruin it.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  8. #8
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    Quote Originally Posted by TGTimm View Post
    Any iron or galvanized pipe in your plumbing system will dissolve due to galvanic action, and deposit itself on your copper parts--including the plates inside the HX. I suspect this is where the rusty looking stuff is coming from.

    You may have just doubled or tripled the efficiency of the HX--if you didn't ruin it.
    everything is stainless, but good to know that. taking no chances, new hx's are on the way.

  9. #9
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    There are a few things you could do to check the condition, although you will not be able to see it with your eyes.

    You could run a loop of dyed water through one loop and a clean water through the other side. If you have mixing of color, then you know there is a problem. You could pressure test each channel as well by pressurizing and then blocking it (valve) for a period of time to see if there is a drop in pressure (temperature dependent of course). Also if you are worried about picking up something, you could run water test samples to a lab. One control of plain water, and then one of water that has been looped continuously for a period of time (maybe the time it takes you to knock out). I am sure you caused some serious reaction based on what you saw come out, however if it holds pressure and is not leaking into each other (cross contaminating) then it is probably still useable. Some copper going into your wort would not be a negative. The thickness of the copper braising was definitely reduced (based on the colors you saw) but that doesn't mean there isn't plenty left to hold up.

    Those things are beasts made for refrigeration and bio diesel production mainly, so I know they see a lot harsher environments than the typical brewery. Theoretically you could probably run a copper solution through and re-plate the surfaces with copper, but that would just be an experiment and I wouldn't use it in a brewery.

    It sounds like you are taking the best approach however with just getting new ones.

  10. #10
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    Quote Originally Posted by UnFermentable View Post
    There are a few things you could do to check the condition, although you will not be able to see it with your eyes.

    You could run a loop of dyed water through one loop and a clean water through the other side. If you have mixing of color, then you know there is a problem. You could pressure test each channel as well by pressurizing and then blocking it (valve) for a period of time to see if there is a drop in pressure (temperature dependent of course). Also if you are worried about picking up something, you could run water test samples to a lab. One control of plain water, and then one of water that has been looped continuously for a period of time (maybe the time it takes you to knock out). I am sure you caused some serious reaction based on what you saw come out, however if it holds pressure and is not leaking into each other (cross contaminating) then it is probably still useable. Some copper going into your wort would not be a negative. The thickness of the copper braising was definitely reduced (based on the colors you saw) but that doesn't mean there isn't plenty left to hold up.

    Those things are beasts made for refrigeration and bio diesel production mainly, so I know they see a lot harsher environments than the typical brewery. Theoretically you could probably run a copper solution through and re-plate the surfaces with copper, but that would just be an experiment and I wouldn't use it in a brewery.

    It sounds like you are taking the best approach however with just getting new ones.
    great advice and ideas. i like the dye one, an easy way to see if the two liquids are mixing. if the final product weren't destined for human consumption i'd probably go ahead and use them. i'll put 'em up for sale on the local version of eBay we've got down here. cheers.

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