HERMS diy vent - stuck mash

[carlafrac]

Hello there, I've had problems with stuck mash in a herms 250l all diy made.
We destroyed the FB in the first mash and made a new one stronger. We were never able to use all the herms system due to the stuck mash and after reading more about our pump I realise we were using too long rose before it and the wrong angle between the pump and the vessel. All this could have lead to cavitation process and mal function of the pump creating too much pressure in the MLT.

I've done some changes and after reading about the vent that people add in the bottom of the FB I've tryied to make a diy with some stuff that I have here, without making a new hole in the vessel. The only problem is that I'm trying to make it work outside the MLT, with a T before the pump. I assume that if I have problems again I must turn the pump off and then open the valve of the tube.

What do you guys and girls think? It will work?
Sorry about my english, it's quite hard to get information and help about herms system in brazilian forums.

 

[day_trippr]

I suspect that vent isn't going to do what you want it to do.
If you leave the upper end open the pump isn't going to pull wort out of the MLT, it's going to suck air through that vent, because it's easier to pull air than wort.

Back to your actual problem, if you destroyed a false bottom it was because your pump was pulling hard against a stuck mash.
The pump almost certainly wasn't cavitating BEFORE the mash stuck.

Here's an example of that phenomenon (from an HBT thread)

Venting the FB through the outlet as shown isn't going to solve that.
At best all it's going to do is aerate the wort which will in effect reduce the recirculation; at worst, you'll be sucking nothing but air.

Bottom line, you need to solve the stuck mash thing.

fwiw, I run a ~40L herms system using three 20 gallon kettles (a baby compared to your system ) and my standard practice is to let the mash sit for 5 minutes after an under-let dough-in, then SLOWLY start recirculation through the hlt hex, stopping with the pump output valve roughly 1/4 open - roughly one gallon per minute.

I'll run like that until the wort starts running clear, then SLOWLY increase the flow to roughly three gallons per minute. This is still well below the pump's capabilities, but it's plenty of flow through the system to maintain the mash temp without a big risk of compacting the mash bed. And I've never had a stuck mash doing this...

Cheers!

 

[carlafrac]

I suspect that vent isn't going to do what you want it to do.
If you leave the upper end open the pump isn't going to pull wort out of the MLT, it's going to suck air through that vent, because it's easier to pull air than wort.

Back to your actual problem, if you destroyed a false bottom it was because your pump was pulling hard against a stuck mash.
The pump almost certainly wasn't cavitating BEFORE the mash stuck.

Here's an example of that phenomenon (from an HBT thread)

Venting the FB through the outlet as shown isn't going to solve that.
At best all it's going to do is aerate the wort which will in effect reduce the recirculation; at worst, you'll be sucking nothing but air.

Bottom line, you need to solve the stuck mash thing.

fwiw, I run a ~40L herms system using three 20 gallon kettles (a baby compared to your system ) and my standard practice is to let the mash sit for 5 minutes after an under-let dough-in, then SLOWLY start recirculation through the hlt hex, stopping with the pump output valve roughly 1/4 open - roughly one gallon per minute.

I'll run like that until the wort starts running clear, then SLOWLY increase the flow to roughly three gallons per minute. This is still well below the pump's capabilities, but it's plenty of flow through the system to maintain the mash temp without a big risk of compacting the mash bed. And I've never had a stuck mash doing this...

Cheers!

I think that when we put all this system together we were so happy that we didn't pay atention to the pump capacity, we just assumed that everything would work out and didn't do a proper research about using those pumps and roses before it. I don't have to say that was a big fail.

At the moment we have a 0.5cv 3.450 rpm, a 0.5cv 1.750rpm and a 1cv 1.750 rpm. (that 1cv was a big mistake I know, to use it I would have to buy another eletrical thing to conect it in my system to be able to reduce the working capacity so I'm not going to use it now maybe I'll try to sell it)

So I will use that 0.5 low rpm to recirculate and sparge and the 0.5 high rpm to send the wort to the kettle and then the chiller and to the brite tank. I don't think I will use a pump to mix the water in the HLT for now.

Take care!

 

[day_trippr]

I see you have a valve on the output of that pump, that should be all you actually need to control the flow and "sneak up" to the optimal recirculation rate.

I also see the pump head is 180° rotated from its optimal position.
The outlet should be above the center, not below it, to minimize the pump
head volume subject to trapping air...

Cheers!

 

[carlafrac]

I see you have a valve on the output of that pump, that should be all you actually need to control the flow and "sneak up" to the optimal recirculation rate.

I also see the pump head is 180° rotated from its optimal position.
The outlet should be above the center, not below it, to minimize the pump
head volume subject to trapping air...

Cheers!

hey, I had no problem with stuck mash! I didn't have to use that diy stuff. Probably taking it out next time to free the space to a termometer.
False bottom was fine too.