MLT does not equalize HLT

Tlpegg001 · Joined: 10 Jul 2015 Posts: 7

So I finally got my set up going. I have brewed two times and both times I noticed the mash ton was not equalizing with the hot liquor tank. To get the MLT up to the desired 154° I would have to set the hot liquor tank to 169°. My set up is very similar to Kal's plan. I noticed I had a couple hoses about 12 inches too long and I've cut those down. I do not use Brinkman kettles, mine were made by Concord and purchased on eBay. I have a 50 foot coil in my HLT that was purchased by stainless steel brewing. My PID's are functioning correctly and my temperature probes are calibrated. During my last trial I took the temperature of the water flowing out of the mash tank hose, I noticed it was much lower about 2 to 3° then the HLT water temp. The suction on my tanks is pretty close to the bottom of my kettles, could I be transferring heat to my stainless steel table which is causing a high Delta T between the two tanks? My pumps are chuggers with stainless steel heads. My kettles are 1 mm thick for the eBay webpage. The only other thing I can think that it is is the coil isn't transferring enough of the heat from the HLT.

My water test tonight took an hour to go from 144 to 151

Any thoughts from the masses would be much appreciated thank you.

**kal** · Posted: Fri Jul 10, 2015 1:21 pm Post subject: Re: MLT does not equalize HLT

Tlpegg001 · Joined: 10 Jul 2015 Posts: 7

You are correct, like your design in concept not in practice, sorry for implying as much.

So we need more info:

- What size kettles?
80 QT 1.0 mm thick

- What batch size were you doing?
10 gallon batch (test run had 6 gallons in MLT)

- What wattage heating elements?
5500 W

- Are you sure the heating elements are being fed 240V and not 120V? Ie: What's the amp meter read when the HLT element is firing?
yes 240 V feed, is approx 27-29 amps HLT hits 154 fine,

- What's the temperature of the sweet wort coming out of the HERMS coil (as it heads back to the MLT)? It should be equal to the HLT temp.

It does not equal, that is what does not make sense... It's almost like the there is no heat transfer

- What sort of false bottom?
Stamped screen on the MLT, nothing on the HLT. The screen is not flat, it has a similar geometry to a flattened top hat.

- What's your crush like? What was the mill gap set to? If crushed too fine you may get poor flow. I recommend 0.045" to 0.050". The hour long ramp was with water only, so grain was not relevant.

Something somewhere is different causing these issues.

My hoses were about 12 inches too long, but I have corrected that.

I am loosing heat somewhere.... I will follow up with pics

Tlpegg001 · Joined: 10 Jul 2015 Posts: 7

One clarification...

During the test run the HLT was filled above the coil.

**kal** · Posted: Fri Jul 10, 2015 3:11 pm Post subject: Re: Reply

foomench · Posted: Fri Jul 10, 2015 6:16 pm Post subject: Re: Reply

huaco · Joined: 05 Apr 2012 Posts: 1506 Location: Burleson Texas

What is the ID of your HERMS coil? Too little volume/flow makes for tough times when it comes to changing the thermal mass of the MLT. It would be very interesting to see what your actual HERMS input temp vs. output temps are. Also, consider the thickness of the walls of your HERMS coil. I talked to a guy that had some crazy-thick-wall tubing and he was also having trouble with thermal transfer. (Stainless, not copper) Likewise, I've got buddies who hate their HERMS because they are using a 3/8"OD HERMS coil. They have issues with it getting plugged by stray grains and when it's not plugged, they simply can't flow enough heated volume of wort to effectively step their mash. They can only maintain the mash if it isn't windy or too cold.

My 50' HERMS coil is 1/2" OD copper and I consistently have a 2°F delta from mash temp to HERMS.

VaWineSnob · Joined: 14 Jun 2011 Posts: 89

Tlpegg001 · Joined: 10 Jul 2015 Posts: 7

I reran the test again using full HLT and 6 gallon in MLT. Valves wide open, chugger chugging. It appears that my system for what ever reason has a 6° offset. When the HLT has a set point of 160 I can achieve 154 in the MLT. Here are some pics

The first Pic shows the Control panel reading. Mind the amp meter, that is why I said the 27-29, it actual bounces around. I checked the output voltage of the VR and it was 11 V.. oops. Not sure If this would affect the AMP meter accuracy or not but dialed in the Pot anyway, running about 4.06 V now. I checked the amps of the hot line to the HLT coil with a clamp on Amp meter, it was reading 22.8 -23.1 amp when running.

Looking at the picture of the control panel again, you can see the temp through the probe on the HLT is 159. Looking at the hose in the HLT that comes out of the HERMS coil you will see the temp as 155, A 4 deg Delta. Both probes confirmed accurate with thermo pen. As of this point, it look like I just might plan on running the HLT 6 deg hotter.

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hopster54 · Joined: 11 May 2014 Posts: 188 Location: Vancouver, Canada

I see in all your pics you are pumping from your MLT to the top of your herms coil,switch your hoses around and pump from MLT to bottom of herms coil then out from top of herms coil to MLT.

Return water elbow inside your HLT should be at a 45 degree angle to aid in better recirculation in HLT.

On your mash tun screen,you are using a false bottom designed for a sanke keg,that false bottom is way to small for the diameter of pot you have and will cause you big problems when mashing-poor flow and not good efficency.

I am not an expert, my system is built but not in use yet.

Just my take on what i see,a little insulation under your pots wouldnt hurt either to prevent thermal transfer to your table,everything helps to maintain temps.

good luck

Mug

Just a thought---have you ever had the impellers out of your pumps and reinstalled them backwards= very poor flow possibly.

Tlpegg001 · Joined: 10 Jul 2015 Posts: 7

Do you know of an alternative false bottom?

Kazumichan · Posted: Sat Jul 11, 2015 5:39 pm Post subject:

I would think a false bottom sort of like this would work. http://www.norcalbrewingsolutions.com/store/False_Bottom_Spike_Brewing_20_Gallon.html

On another note, I would get rid of the 90 elbow on the outlet of your pumps. It does look like you really need it, and it is just cutting your flow down.

Tlpegg001 · Joined: 10 Jul 2015 Posts: 7

Thanks for the feedback.

I have good flow, so the elbows are of little consequence. As far as the false bottom, and after reviewing how to brew (Palmer) chapter, does the false bottom really make that much of a difference? Does the gap (space under the bottom) allow for more even wort flow through the grain bed? I have missed targets, but attribute that to my temperature issues.

Thoughts?

Gameface · Joined: 07 Feb 2015 Posts: 120 Location: West Jordan, UT

**kal** · Posted: Sun Jul 12, 2015 1:16 pm Post subject:

Note that all these comments about the false bottom only apply when you actually go to brew with grain. For these tests that only use water, how well (or not well) the false bottom would work with grain doesn't matter.

Kal

Tlpegg001 · Joined: 10 Jul 2015 Posts: 7

Jerz · Posted: Mon Jul 13, 2015 3:32 am Post subject:

Tungsten · Joined: 06 Dec 2014 Posts: 318 Location: Buffalo, NY

This is really perplexing. Everytime I think of something else that could be the problem, I think "no... that wouldn't matter" or "he's already ruled that out" or "that still doesn't explain why his temp isn't even equalizing in the HERMS coil"... frustrating!

Tennessee · Joined: 04 Apr 2015 Posts: 116 Location: Tennessee

Have you checked your flow rate ? I ran a simple test on my (Kal Clone) system
and taking a one gallon sample of water, from the sparge tube it filled in 35 seconds.
Which is about right for a March 809 with a 4 foot head
It might rule out the pump and coil. Did you pull all your connections
to see if one of the O-rings turned on ya ?

David_H · Posted: Mon Aug 03, 2015 3:07 pm Post subject:

Here is my two cents.
I pump the wort into the top of the HLT and out the bottom. The bottom will always be covered in hot water and therefore should be the hotest wort.
The thermal inefficiencies of the entire system shouldn't matter, the only heat transfer that matters is between the SS HE and the loss between the HLT and MLT. The heat transfer at the SS HE should be the same for everyone and the temperature loss in the silicone tubing should be nil.
The important temperatures are the temp at the bottom of the MLT (this should be the reading on the panel), the temp of the HLT (again panel) and the temp of the wort as it flows into the MLT.
Following Occam's Razor, the simplest solution often prevails; I suspect temperature probe calibration. Double check all of your temperature measurements. Make sure they all read the same temperature. Try switching the probe leads between the MLT and HLT to see if you get a change in reading (just to see the temperatures not for operation).

JMTC.

David