Bohemian Monobloc Heat Exchanger clogged -- disassemble or caustic?

[Eric Brewer]

The title pretty much says it all.

My Russian Imperial Stout went NOWHERE today. Backflushing with hot wort didn't work. So I pumped the hot wort into a fermenter so the glycol system can chill it. I'll deal with it tomorrow.

I am told the heat exchanger has never been disassembled and cleaned. On my last system, this was a three hour job. But my last heat exchanger didn't have a glycol loop -- just wort and water. Super simple.

Those of you who have brewed on a Bohemian -- what am I in for if I try? I can certainly back-flush with caustic, but that was never enough with my last heat exchanger.

Any sage advice out there?


Thanks!

Eric

EDIT -- The exchanger was caustic cleaned, rinsed, acid cleaned and sanitized before use. I think the 1 lb of hops per barrel of wort had something to do with the clog. Sorry about being obtuse. It's been a long frikkin' day.

[dick murton]

It sounds as though a total strip down will be the only option. If you can't backflush, then it sounds as though it is totall blocked with hops and probably other debris.

Check the cleaning flow rate after you rebuild it - 100 to 150 % of nominal forward flow rate (wort cooling), depending upon the suppliers preference, but genrally they are better for higher flow rates than jsut achieving 100 %

[Jephro]

On the whole i agree with Dick, if its got enough crud in to clog- you need to break it down. Do a search on here for some good avice on how to and what to be prepared for. Gaskets, glue, keeping plates in order, torque on bolts etc.

A couple side thoughts...

Are you using whole hops or pellets?

It seems odd that it would just suddenly be completely cloged. Is it possible that you froze it? (i.e. did you have your glycol or prechiller running before you started to run wort through it?)

[Eric Brewer]

I'm new at this brewery. I've run 100BBL through the HE, and I haven't been happy with the flow rate from the get-go.

I haven't been running the glycol loop, so no chance of freezing it.


I was able to backflush this morning. But even with 200f water and a strong pump, my max. flowrate was 1-to-2 gallons per minute.

I'll search for the thread on stripping the HE.


I'm going to need glue?!?!?

[Mad-Brewer]

I had this happen a couple years ago, and was able to clear it. I attached it with hot caustic it pulses of backflow. I let it sit, then pushed more in place. I then did the same with hot, very strong acid. I spent a few days at this, but it run fast and plated clean.

[Natrat]

I'm going to suggest using a scrubbie (best is the fine grey or burgundy Norton Beartex pads) and caustic on all your plates. If your HX was cruddy enough to clog, then I almost guarantee there will be biofilm on your plates. The only way to remove that stuff is scraping or scrubbing.

Give yourself an entire non-brew day for breakdown and cleaning. It's miserable, but a clean HX will make your cooling way more efficient, and your beer better.

The HX is the #1 source of infection for most breweries. Some of the critters that live in there don't need much of an inoculation to impact your beer.

The last time I helped clean a *clogged* HX, it had MOLD growing inside...and it was backflushed, cleaned, passivated, and pasteurized every brew. Gross...

Nat

[mmussen]

I agree - you should strip it apart and clean every plate - I've found some amazing piles of curd stuck between plates before.

Before you start working on it - get in touch with the manufacturer of the heat ex and find out what you'll need to put it back together - Make sure you're got spare gaskets on hand, glue if your unit calls for it.
Plan on it taking at least 2 days - it can be a real pain.
There is a thread on breaking down and cleaning heat exchangers here on probrewer loaded with good advice.

[BeersmithMT]

Eric,

I won't repeat other suggestions above (they're all good). I have broken down a Monobloc 15bbl Fischer heatex a couple of times, although its been a few years. It's pretty straightforward, just make sure:

keep your plates in order
-you can # each one with a marker (but might come in cleaning)
- or scratch/nick a line diagonally down the outside of the plate/fins, its impossible to lose the plate's position that way
-or just clean them in order and don't walk away from them..

Before you break down, measure the distance from the outside of each end plate, that way you'll know when you have the plates compressed for the proper seal.

I had glue handy for the breakdowns, but did not need it. Sorry I can't remember exactly which glue we had.

When reassembling, tighten the nuts in rotation -just like your lug nuts on a car wheel.

Hope that helps and have fun! -Brian

[brewman21]

You probably have a "Fischer" brand H/X, if it came with the Bohemian Mono-Bloc. I Still have my manual that came with it over 15 years ago.It has all the
assembly/disassembly,schematics, and cleaning instructions,etc. But I have a 5BBL mono-bloc and you a 10 BBl, which has much wider H/X. I have broke apart both 5&10 BBL H/X many of times. If you have any questions, you can give me a call at 906-458-5667. I added a link below to a source for Fischer
heat ex-changer parts. Hope this helps!!! Cheers!!! "Chumly"


http://www.plough-gaskets-direct.com/fischer-c-124.html

[Eric Brewer]

Thanks so much for the replies. I'll try Brewery Gaskets here in Vegas first -- I could walk there from the brewery. Shipping is going to be a lot worse buying from Plough.

It is indeed a Fischer HX.


I'm pretty good working on these things, but thanks for the phone # in case I hit a brick wall.


My first step when working on a new piece of equipment is to charge up my camera and load a new SD card -- that way I have a photographic record of how I took it apart. Makes reassembly a lot easier down the road.


Thanks again!

[Eric Brewer]

stripped it down, whacked it with a pressure washer and put it back together.

The last 20 or so plates (closest to the boiler) were crusted with 1/16" thick congealed wort -- it took several minutes per plate to blast the gunk out. I felt like a dental hygienist working on Austin Powers.

I wish I had weighed HX before and after. I bet it was about 20 pounds of crud.

[tarmadilo]

Wow, not much to add, but if you aren't doing it already, I always cleaned my HE by backflushing, first with hot water, then hot caustic. Seemed to get a lot more crud out than by pumping in the same direction...

Cheers, Tim

[Jephro]

Glad to hear it went well for you

One of these days I'm going to grow the grapes to break this one down, i don't think it has ever been done so it probably needs it.... but on the other hand i like the old addage "if it ain't broke, don't fix it".

Couple other tricks i use for CIP:

Pulsing during cleaning cycles - quickly open and close the valve on the out flow from the HX (i generally quickly pulse 6-12 times, let it run full open for 20-30 sec & repeat this 3 or 4 times)- I will do this every 5-10 minutes while the cycle is running alternating every other 5-10 min cycle either full open outflow or restricted outflow (+/-half open).

... and to prevent the crud knocked loose during pulsing (or even just a regular CIP) from re-entering the HX just to get caught somewhere else i always install a sock screen gasket inside of a sight glass somewhere in-line between the HX outflow and the pump. And as mentioned above i like the backflushes too, I will remove and clean the sock screen, rinse the HX, put new chems in for a reverse flow CIP (backflush) reinstall the sock screen gasket which always seems to catch a bit more crud.

[Eric Brewer]

I've always done the same cleaning regimen as most people here -- backflush with hot water, then caustic, then rinse (and sani before use).

But when flow rates drop to a trickle, it's worth it to take half a day to take the HX apart and clean it -- pays dividends every brew day.

I'll try the pulse thing, for sure.