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  • Issue With Heat Exchanger

    We've been having issues lately with our heat exchanger not cooling as efficiently as it used to. We clean the HX every day after brewing and once a month break it down to check the plates and scrub them if they need it. It started cooling slightly less efficiently a few months ago and it's starting to really lag as of late. We're having to crack back valves to give the wort more time in the HX resulting in cooling times approaching and exceeding an hour for a ~17bbl batch.

    My question is: Has anyone else ever had this issue and is there a simple fix that I'm just not paying attention to? My fear is that maybe somewhere along the line one of the plates got removed and put in incorrectly and that's what's causing the issue, but I want to check before shutting down another day to tear it apart again.

    Any help would be greatly appreciated!

    -Josh Ward
    Head Brewer/Brewing Operations Manager
    Grand Canyon Brewing Company

  • #2
    Sunlight on that black CLT could be super-heating your water. What the CLT temp reading? Are all thermometers correctly calibrated? Are all lines flowing properly, like is your CLT pump working at it's full flow rate? I ask because I'm using city water and my water pressure is low and it's a problem.

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    • #3
      Thermometers are good, water flow is good (our return water from the HX is filling the HLT at the normal rate) and the thermal exchange is occurring (water on the outlet of the HX is coming out plenty hot). CLT is variable but not any hotter than last summer when I first started here.

      -Josh

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      • #4
        Had the same problem with the heat exchanger gradually becoming less efficient in spite of almost daily CIP'ing. We found out that we have to start CIP at 90C+ to dissolve, what I assume was malt-sugar caramel burned on the plates. After that we have had stable cooling times.

        Originally posted by grandcanyonbrew View Post
        We've been having issues lately with our heat exchanger not cooling as efficiently as it used to. We clean the HX every day after brewing and once a month break it down to check the plates and scrub them if they need it. It started cooling slightly less efficiently a few months ago and it's starting to really lag as of late. We're having to crack back valves to give the wort more time in the HX resulting in cooling times approaching and exceeding an hour for a ~17bbl batch.

        My question is: Has anyone else ever had this issue and is there a simple fix that I'm just not paying attention to? My fear is that maybe somewhere along the line one of the plates got removed and put in incorrectly and that's what's causing the issue, but I want to check before shutting down another day to tear it apart again.

        Any help would be greatly appreciated!

        -Josh Ward
        Head Brewer/Brewing Operations Manager
        Grand Canyon Brewing Company

        Comment


        • #5
          If you're not already, I'd recommend using an oxidizer additive to your caustic CIP solution in the last 10-15 minutes of CIP. It should be available through your chemical supplier. It's typically percarbonate base or metasilicate based powder, or high strength hydrogen peroxide. It does a fantastic job of removing both protein and mineral/ carb build up on a daily basis. I'd highly recommend it for your hot side all together. I typically run chlorinated caustic about once a month as well to really get to neutral. But if you're good with your cleaning practices, then I'm stumped.


          Sent from my iPhone using Tapatalk

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          • #6
            I suspect that you are right in that one or more of the plates are misplaced and/or reversed. You should be able to get a diagram of the plates from the HX manufacturer. Good luck understanding it.

            Once you have all the plates in their proper place and orientation, paint a diagonal line down each edge of the plates. This will make any displacement obvious.

            Breaking down and cleaning the HX every month is massive overkill. Your CIP should be doing the job.
            Timm Turrentine

            Brewerywright,
            Terminal Gravity Brewing,
            Enterprise. Oregon.

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            • #7
              You should also backflush the HX first, then run CIP backwards through HX. Then back flush again to rinse. Sanitize CIP running forward and leave packed overnight.
              Todd G Hicks
              BeerDenizen Brewing Services

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              • #8
                Originally posted by TGTimm View Post
                I suspect that you are right in that one or more of the plates are misplaced and/or reversed. You should be able to get a diagram of the plates from the HX manufacturer. Good luck understanding it.

                Once you have all the plates in their proper place and orientation, paint a diagonal line down each edge of the plates. This will make any displacement obvious.

                Breaking down and cleaning the HX every month is massive overkill. Your CIP should be doing the job.
                Yeah, that's kind of where I'm at now. I'm confident in our CIP proceedure, and unless I'm understanding the HX totally wrong, we're getting great flow through it, just not the cooling we used to (though the cold water is still heating up well). Great idea on future preventative practice with the diagonal line. We'll just have to shut 'er down I s'pose.

                Thanks all,

                Josh

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                • #9
                  Originally posted by grandcanyonbrew View Post
                  Yeah, that's kind of where I'm at now. I'm confident in our CIP proceedure, and unless I'm understanding the HX totally wrong, we're getting great flow through it, just not the cooling we used to (though the cold water is still heating up well). Great idea on future preventative practice with the diagonal line. We'll just have to shut 'er down I s'pose.

                  Thanks all,

                  Josh
                  Josh,

                  Did you ever find the culprit? I'd love to know what the solution ended up being.

                  Rob
                  Last edited by RobertColianni; 08-06-2015, 02:14 PM.
                  Robert Colianni

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                  • #10
                    If it turns out it is not the misaligned plate issue, it could be hard water deposits. I've found that I get a fair bit of hard water buildup on the CLT side of my plates and I rarely CIP the CLT side of my plates. Could be hard water deposits slowing the heat exchange rate from the CLT side. This could explain the good flow rate without a decent HX rate.

                    Could also be the direction of flow for the CLT and wort. The cold water and wort are moving in opposite directions through the plates, correct? If they're moving in the same direction through the plates the HX would also lose efficiency without a reduction in flow rate.

                    Hope you figure it out!

                    Reno
                    Poseidon Brewing
                    Ventura, CA
                    Last edited by poseidonbrewing; 08-06-2015, 05:32 PM.

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                    • #11
                      Any chance you've accidentally got the wort and cold water running the same direction?

                      FWIW, it takes me 2+ hours to knock out 3.5 barrels on what my "boss" INSISTS is an appropriately sized HX. So it could always be worse.

                      Sent from my Nexus 5 using Tapatalk

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                      • #12
                        Do you happen to know the flowrate? I know ours is a steady 5 GPM with the pump we use. Once the plate stack fell and was loaded back in wrong order. It is a dual stage with 75% water and 25% glycol chilling. We were getting crazy knockout with water and wort throttled (200f down to 40f) but half the flowrate. Turns out the wort would basically flow into the hx, deadend, and then backflow to exit because plate order was so jacked up. The glycol was taking alot more heat load than normal. I really like the idea of painting a line to show incorrect plate order.

                        Outside of verifying correct plate sequence, it could be buildup in the cooling side, or wort side. We use 5star chems. Acid wash at 140 backwards for 15 min will be somewhat clear. Rinsing and then doing PBW at 140 for about 20-30 min will instantly look like gatorade or a porter depending on wort run through it. The acid breaks it up, and the PBW melts it away.

                        Also "barking" (opening and closing) the valve helps build up and release pressure which seems to knock alot of material loose as well. Use a strainer if you're using the acid wash as it will peel an almost film like coating of soil that will just keeping recircing through HX, pump and hoses.

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