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ace1797
10-19-2006, 01:54 PM
I have a chiller system that has been sitting around. I never needed it before, but we are getting ready to bottle and need to bring down the temperature of the beer. Right now all tanks are in a cold room. Single wall tanks that we fitted with a cooling loop inside of tanks.
I have a 5 ton compressor with a basic counter flow heat exchanger.
A 125 gal. reservoir tank and 2 pumps.
Glycol leaves tank goes to pump then through a solenoid valve and then to heat exchanger, and back to tank.
Refrigerant leaves compressor goes through solenoid valve then expansion valve and through heat exchanger and back to comprssor.

My question is does the t-stat control both solenoid valves and the pump?

On my loop to my four 7bbl. tanks do I need some sort of pressure relief valve? And if so what do you recomend?

This will be a great starting point for me.

Thanks in advance,
Adrian

jimvgjr
10-19-2006, 08:03 PM
.

My question is does the t-stat control both solenoid valves and the pump?

On my loop to my four 7bbl. tanks do I need some sort of pressure relief valve? And if so what do you recomend?


Your refrigerant solenoid valve should be controlled by a t-stat sensing the glycol temperature. When your glycol tank reaches setpoint, the refrigerant solenoid valve is closed, it will then pump the system down and your compressor will shut off. I wouldn't shut the glycol pump off with this stat as you could freeze up before the compressor can pump down. We cycle the evaporator glycol pump OFF using a Delay On Break Timer that shuts the pump off after the solenoid is de-energized for about 120 seconds, allowing the compressor time to pump down and shut OFF.

The glycol solenoids are typically installed on each tank and controlled by t-stats sensing the fermenter temperature.

It is a good idea to install a pressure bypass in your glycol loop. I am currently out of the office and don't have the model to recommend, I will post more on the bypass tomorrow.

Please feel free to contact me directly with any additional questions.

Good luck,

Jim VanderGiessen Jr
Pro Refrigeration Inc.
800-845-7781

jimvgjr
10-20-2006, 10:01 AM
Installing a pressure bypass valve in your glycol supply line serves a couple purposes:

First it can provide some protection against over pressurization of the tank jackets. Confirm the jacket ratings before ordering a pressure bypass valve, a typical bypass setting would be 10-15 PSI.

Secondly these bypass valves will protect your glycol pump from a "dead head" situation where all of the jackets are closed and the flow is stopped. During these conditions, a centrifugal pump will continue to run and will generate some tremendous heat. This can lead to failure of your pump seals or actual melting of any PVC fittings at or near the pump- both of these would cause loss of glycol and could be costly and damage your system (especially with glycol prices over $12/gallon).

McMaster Carr has some valves on their sight, a 1" valve sells for about $120.00. They offer several relief spring options you can select depending on the jacket pressure ratings. They make it a challenge to hyperlink to a specific page on their site, but you can enter the following part number in their search form and it will take you to the page:

part # 4703K562
http://www.mcmaster.com/

There is a typical brewery flow illustration in an article on glycol we have posted on our website- and in the refrigeration section of this site. The illustration shows the location of the bypass valve in the glycol loop. You can download a PDF of the article off our website (the flow illustration is much larger in the PDF than the .jpg posted on this site). http://www.prochiller.com/files/AllAboutGlycol.pdf

Hope this helps.

Jim