Glycol problem, Help!

[mongo]

Hi,

I installed a new glycol system, the unit moves 15 gallons of 28 degree glycol in a loop, with cut-outs for solenoid valves hooked to temperature controllers. The lines are aqua pex 3/4 inch. There are 2 fermenters and 2 serving tanks hooked up to this system. The problem is, nothing is getting chilled! The glycol is moving, but maybe not quickly enough? There is no rise in the glycol bath, which seems to indicate a flow problem. The pump is powered by a 3/4 HP motor. Any thoughts?

Thanks!

[lhall]

Do you have a valve separating the supply and return sides of your loop? What is the pressure in the supply side?

[mongo]

Do you have a valve separating the supply and return sides of your loop? What is the pressure in the supply side?

I don't. But I'm going to get several of them now, as that's been recommended. Also a pressure gauge.....

[beertje46]

Throw an inline thermometer on the supply/return lines and pressure gauges on both so you can monitor drop across your system. Your pump is big enough if you don't have any crazy rise in your loop.

[Moonlight]

Did you correctly plumb the glycol supply to the bottom jacket fitting on the beer tanks, and exit at the top of the jackets? This will flood the jackets and allow far better cooling than the reverse.

[kramling]

A few things to look at(In addition to what everyone else has said):


Is there any glycol flow coming back to the glycol reservoir?


Make sure your temp sensors are firmly placed in the thermowells of fermenters and serving tanks. Use a thermal paste for better accuracy.


Make sure you're solenoids are getting powered when the temp controller gets triggered.


Look to see if the solenoids are normally closed or normally open.


Make sure your solenoids have a zero pressure differential or close to it. Not enough pressure may make the solenoids not work.


Make sure the solenoids are oriented in the right direction for the flow. Believe me I have done this dumb move on accident. :-(


Ideally you should have a manual bypass built in in case of solenoid failure.


BTW how big are these fermenters and serving tanks? 3/4" is very small for supply and return line. Also 15 gallons is a very small volume of glycol. Anything bigger than 3BBL and I would think you are going to have problems cooling, especially if you are using this for you're heat exchanger at knockout.


I would also recommend the first in last out method described on the Pro Refrigeration website for balanced glycol flow through all tanks and a PRV in case all your solenoids are shut to prevent ruptured pipes.


Cheers,
Steve

[kugeman]

Do you have a vacuum break/air lock on the highest point in the system so that no air can be trapped in the system?

[Meheen]

Sounds like you need a loop setter. This is a very simple thing to do. After the last tank in the system place a restriction in the line to create a differential pressure between the supply and return side of the loop. This restriction can be something as simple as a plug with say a 1/4" hole for example. Also make sure all the return lines from the tanks are connected to the return loop after the loop setter restriction.

Besides creating the differential pressure needed, the loop setter allows for continued flow through the loop when none of the tanks are using cooling. Don't for get your coldest gylcol should go into the bottom of the jacket to keep thermal conductivity moving the beer.

Dave

[kramling]

Another option to consider:

I use an adjustable pressure bypass valve to accomplish the same thing. It's also mounted in line at the end of the supply line but is only active if the solenoids before it are all closed. I dial it in to kick in at a certain pressure. That way the flow is either through the FV's and Serving tanks or the adjustable pressure bypass valve. Not both at the same time. Picked it up from McMaster-Carr

4703K562
(Same as 4703K56)
Extended-Life Adjustable Relief Valve Bronze Body, 1" NPT, 15 - 25 PSI
In stock at $130.63 Each

Cheers,
Steve