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Georgeous

Mash Tun not Heating

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I have a 600 gallon mash tun and a 600 gallon still, they are heated by a brand new installed 15hp / 15psi fulton boiler. i can heat the still just fine but the mash tun will not heat above 126°F. We cleaned the steam traps blew out the heating jackets with water to make sure they are not clogged. We left the boiler on over night and it di not rise in the slightest only maintained  the 126°F

I initially got the water up to 130 °F and put in my corn, after that all the problems with heat rise

 

I need help 

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Do you have pressure gauges installed on your still and mash-tun jackets?  What PSI is the mash tun jacket holding while you are trying to heat?  Knowing this would help narrow down the problem. 

(presumably you have a pressure relief valve, vacuum relief valve, and pressure gauge on the jacket after the steam input valve.)

Is steam trap installed in the correct direction/flow?  (They typically have an arrow on the cast iron housing.)
Do you have a condensate return pump?  (can you hear is cycling on/off)
Whats the pressure on the boiler itself once you top out at 126F?

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I'm assuming you are heating them at different times, not at the same time?

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7 minutes ago, ChrisSD said:

I'm assuming you are heating them at different times, not at the same time?

yes correct, not even using the still now. when boiler was first installed we tested it and worked great. we did our first mash yesterday and cannnot heat up. Mash Tun is right next to boiler, Still is 40ft away and works fine last time we tried it. filling it with water now to test its heat up. This is all first time use 

 

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8 minutes ago, ChrisSD said:

I'm assuming you are heating them at different times, not at the same time?

15hp boiler is about 500,000 btu right?  That does seem small for a pair of 600 gallon tanks..

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12 minutes ago, HedgeBird said:

Do you have pressure gauges installed on your still and mash-tun jackets?  What PSI is the mash tun jacket holding while you are trying to heat?  Knowing this would help narrow down the problem. 

(presumably you have a pressure relief valve, vacuum relief valve, and pressure gauge on the jacket after the steam input valve.)

Is steam trap installed in the correct direction/flow?  (They typically have an arrow on the cast iron housing.)
Do you have a condensate return pump?  (can you hear is cycling on/off)
Whats the pressure on the boiler itself once you top out at 126F?

pressure gauge on boiler goes up to 13.5psi and stops when it drops 2 psi kicks back on. mash tun pressure gauge shows exactly the same. we do not have condensate return pump, during heating mash tun jacket holds 13.5psi

 

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5 minutes ago, Georgeous said:

pressure gauge on boiler goes up to 13.5psi and stops when it drops 2 psi kicks back on. mash tun pressure gauge shows exactly the same. we do not have condensate return pump, during heating mash tun jacket holds 13.5psi

So your boiler is low enough that condensate can gravity flow back to the boiler?

If your just heating up now, perhaps try switching the condensate trap on the still with the one on the mash tun.  That would be a good test to figure out if the trap is your problem.

(assumes they are the same size trap and can be changed out without changing piping, and that you have unions where you need them to change them out, and that you have a pair of pipe wrenches, and pipe dope :))

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With the Delta T required on cooking corn, that size boiler might be struggling too much.  I g

6 minutes ago, HedgeBird said:

15hp boiler is about 500,000 btu right?  That does seem small for a pair of 600 gallon tanks..

That's what I was thinking.  I've figured about 597,000 BTUs with a 120 Degree Delta T.  Cooking corn could have an even bigger swing which is going to make it even tougher considering the amount of time you have to hold the high temps.  I would normally recommend at least a 20hp boiler which essentially includes 15-20% increase for certain situations.

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Just now, ChrisSD said:

With the Delta T required on cooking corn, that size boiler might be struggling too much.  I g

That's what I was thinking.  I've figured about 597,000 BTUs with a 120 Degree Delta T.  Cooking corn could have an even bigger swing which is going to make it even tougher considering the amount of time you have to hold the high temps.  I would normally recommend at least a 20hp boiler which essentially includes 15-20% increase for certain situations.

This may mean he wont be able to heat up both still and mash tun at the same time, and will have a longer heat up time, but if the jacket is holding 13.5psi and not getting hotter. than thats not the specific problem here.  Def sounds like a problem with the trap or return piping..

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2 minutes ago, HedgeBird said:

This may mean he wont be able to heat up both still and mash tun at the same time, and will have a longer heat up time, but if the jacket is holding 13.5psi and not getting hotter. than thats not the specific problem here.  Def sounds like a problem with the trap or return piping..

After reading the above, I'm thinking the same thing!  It's still going to be tough getting to 190 and holding.  It just might take a while!

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For both vessels to be heated at the same time I would have offered you a boiler with an output of 1.2 million BTUs  On my stills that would give a heat up to operating temp time of 1 hr and slightly longer than that for the mash cooker, if both were started at the same time.  However with a boiler output of 506,000 btus there should be no problem heating the mash tun to operating temp in slightly less than 1.5 hrs if you are running it by itself. That being said we know that boiler output is not the problem.  If you do not have a condensate return pump and your boiler is not low enough to gravity feed then that is the culprit.  However I have seen some people use 100% make up water and allow the return condensate go to waste.  That is really hard on your boiler and increases your energy costs dramatically.  Please tell us exactly how the condensate return is set up for your mash tun?

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6 minutes ago, Hudson bay distillers said:

would you gain anything by steam injecting your mash tun to max out the efficiency of the boiler  

Hudson Bay has a very good point.  If you have steam injection ports, that may be the direction that you want to go (especially if you do not have a viable condensate return system) but of course you will, in my opinion, need to add filters unless your boiler has all stainless components in contact with the steam, like some Sussman boilers.

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2 hours ago, HedgeBird said:

15hp boiler is about 500,000 btu right?  That does seem small for a pair of 600 gallon tanks..

we dont heat them in tandem and one at a time. it is rated at 800K btu

 

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2 hours ago, Hudson bay distillers said:

would you gain anything by steam injecting your mash tun to max out the efficiency of the boiler  

not sure how i would do that. the recommended boiler for my system was a 10-12 hp. i went with the 15 as it was not much more but alternately because ibc 509 asks is it greater than 15hp / 15psi  mine is 15hp and 15psi not greater therefore was not required to build a boiler room 

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2 hours ago, Southernhighlander said:

For both vessels to be heated at the same time I would have offered you a boiler with an output of 1.2 million BTUs  On my stills that would give a heat up to operating temp time of 1 hr and slightly longer than that for the mash cooker, if both were started at the same time.  However with a boiler output of 506,000 btus there should be no problem heating the mash tun to operating temp in slightly less than 1.5 hrs if you are running it by itself. That being said we know that boiler output is not the problem.  If you do not have a condensate return pump and your boiler is not low enough to gravity feed then that is the culprit.  However I have seen some people use 100% make up water and allow the return condensate go to waste.  That is really hard on your boiler and increases your energy costs dramatically.  Please tell us exactly how the condensate return is set up for your mash tun?

just updated to show photos of my setup if that helps, condensate is gravity run to the boiler. 

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1 hour ago, Georgeous said:

we dont heat them in tandem and one at a time. it is rated at 800K btu

 

We are talking boiler output BTUs.  It sounds like you are talking boiler input btus.

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1 hour ago, Georgeous said:

just updated to show photos of my setup if that helps, condensate is gravity run to the boiler. 

It looks like it is gravity fed for about 1 ft. and then turns toward the vertical pipe that is wrapped in insulation?  If that is correct, you need a pump/lift station to send back to the boiler.  Those vertical runs of pipe completely take the gravity out of the equation without a pump.

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I concur with Chris.

23 minutes ago, ChrisSD said:

It looks like it is gravity fed for about 1 ft. and then turns toward the vertical pipe that is wrapped in insulation?  If that is correct, you need a pump/lift station to send back to the boiler.  Those vertical runs of pipe completely take the gravity out of the equation without a pump.

 

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1 hour ago, Southernhighlander said:

We are talking boiler output BTUs.  It sounds like you are talking boiler input btus.

You are correct it is 503000 BTUs output

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so we filled the still with 600 gallons of water today just to test. We were at 180°F in about an hour from 60°F. the still sits 40 ft from the boiler. The mash tun is right next to it. Now the still only has one jacket for steam so much for heating area from top to bottom. The mash tun has an upper jacket for chilling and a lower jacket for steam. I thought about plumbing both with steam but how would i cool it down after gelatanizing the corn? But still even with just the lower jacket the temperature should have risen slowly. We left the boiler on over night for about 12 plus hours and temperature did not even rise a single degree. 

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3 hours ago, Georgeous said:

so we filled the still with 600 gallons of water today just to test. We were at 180°F in about an hour from 60°F. the still sits 40 ft from the boiler. The mash tun is right next to it. Now the still only has one jacket for steam so much for heating area from top to bottom. The mash tun has an upper jacket for chilling and a lower jacket for steam. I thought about plumbing both with steam but how would i cool it down after gelatanizing the corn? But still even with just the lower jacket the temperature should have risen slowly. We left the boiler on over night for about 12 plus hours and temperature did not even rise a single degree. 

At first I would almost certainly point at a faulty trap on the MT. As someone suggested above, make sure the arrow on that trap is pointing out of the mash tun and back to the feedwater system. Any chance it was a used trap and higher pressure than 15psi? That looks like a fairly hefty bucket trap. 

So for some reason, you are not transferring BTUs through that steam jacket. Another thought is, are you 100% certain that you have the steam inlet and the trap on the same jacket? I know it sounds like a crazy question but I've almost been guilty of this myself. One quick way to test is to disconnect them both and shoot a little compressed air through them. If you feel the air on the other end, you are good to go (in that sense). If not....you may have your steam/chiller hooked to the same jacket!

Also, one last thing. Were you running an agitator on the mash tun while heating? I'd imagine you could boil without agitating, but the more water you can pull across your heating surface, the greater heat transfer you will have.

 

After looking at your diagrams a bit more...a couple more questions: Is that a valve on the condensate return line, after the trap on the insulated vertical leg? If so, (another crazy question, I know) that's open, right? Also, it looks like you are not running a condensate return pump on that mash tun. Another thought would be that you are having more than 13psi (30 feet of head) loss between your mash tun and feedwater return tank...depending on elevation change, direction change etc. OR if you are not running a feedwater return and running condensate back into the boiler, that could be making the pressure in your condensate return line even higher. The closer your steam feed and condensate return lines are in pressure, the slower your vessel will heat. That is why a condensate return pump is so nice....your trap line has basically 0psi so you can take full advantage of that 13 psi you have on the supply side instead of say only 3-5.

Just my random thoughts for the night while drinking a glass of bourbon and getting caught up on production reporting. Haha. Hope it helps.

Cheers!

Adam

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Georgeous,

Just as confirmation for you, we are running the exact same Fulton boiler (15hp, 2009) with a 600 gallon MT (jacket heated) and a 300 gallon still. We have no problem bringing grain in batches up to boiling in 1.5h if we want.

We can even run both the still and the MT if we are patient and will often mash once the still is at temp.

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Adam

we are not running a condensate return pump. that pump next to the steam trap under the MT is a spare pump i have on the ground. So yes all valves are open, we have option of bypassing solenoid valve in case it fails. So we cleaned out steam trap under MT and left the plug off the bottom of it. Steam went in the inlet and came out of the steam trap at what appeared to be a steady flow of clean steam. the trap was not that dirty, i took a pic. Really sux cause our recipe we bring the water to 130°F then add corn then raise to 185°F and add enzyme, well 840lbs of corn sitting in 126°F water and not rising. Yes we ran the agitator while heating it doesnt seem to help. 

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4 minutes ago, Broken Anvil Distilleries said:

Georgeous,

Just as confirmation for you, we are running the exact same Fulton boiler (15hp, 2009) with a 600 gallon MT (jacket heated) and a 300 gallon still. We have no problem bringing grain in batches up to boiling in 1.5h if we want.

We can even run both the still and the MT if we are patient and will often mash once the still is at temp.

does your MT have two jackets cooling and heating? 

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