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My plumber just finished installing our manifold from the chiller (with runs to chill CLT, fermenters). We worked with manufacturers drawings and what is unfortunately my plumbers overconfidence with installing glycol loops. After finishing the 2" copper pipe, the steam fitter was quick to pick up that we didn't have an air release valve/bleeder valve or a check valve. Reluctant to cut into the copper in two places (check valve after chiller supply and air bleed valve at   the high point) and resolder everything myself, I am looking for some feedback. Note: aside from the absolute hassle, it is quite the short and busy loop, so there are few places to easily cut and rework the fittings.

1) What are the implications of not having a bleeder valve? I am assuming a loss of efficiency and I'm assuming that I will have to recut this portion.

2) Why is a check valve required in a closed loop chiller? I am assuming that without a check valve, the worst that could happen is some chilled glycol return to the holding tank when the chiller is turned off. In my limited knowledge of these matters, I don't see this as being a big deal and worth reworking the system for.

Thanks to all who give this their thoughts.

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On 9/19/2017 at 6:12 PM, Broken Anvil Distilleries said:

2" copper pipe

For what??  We have a 2500 gallon reservoir. We do have a single check valve but don't have any bleeders. We though about adding on at the highest point near  the dephlegmator on our tall column.  Our loop is piped in Schedule 80 PVC.  

 

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Our supply and our return from the chiller are 2" Copper. The recommended material options from the chiller company were industrial ABS (not available in our parts), stainless or copper. We chose to use copper and although necessary, it will feel like a crime to cover it in foam insulation. Our high point in the two inch is between the supply and return (think of a square of 2" copper square strapped to the wall) and any 3/4" offshoots to tanks would start too low for a bleeder to be of value (although those would have been easy to work with since they are pex).

 

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You should be fine without the air bleed. Generally, an air bleed is used for a high-point-press in the scenario that your system becomes air-locked. Generally, most distilleries (at least the ones that are our size) are running a small enough loop that that you generally shouldn't have to worry about that. Honestly, you could probably crack a valve on one of your process tanks to take care of any sort of air lock/dead head scenario.

The check valve is nice to help with hammering and dead head. Imagine for a second that you are running your chiller loop and you shut it off. Everything will then drain to its lowest point without a check valve. That means that when you start up, say only the bottom 8' of your system has fluid in it so as soon as your pump fires, it is going to try to shove a ton of fluid into the air void above. This can cause issues with hammering and can eventually become destructive to not only your piping system, but also your circ pump.

All of that being said, we run with a check valve and no air bleed, but do have a 15 psi PRV that connects our cold side to return side of the chilling loop, so it will kind of act as an air bleed as the system builds pressure.

Long story short, your system will operate without either device, but for equipment reliability and repeatability, the check valve would be first priority with the air bleed/PRV as a second priority.

These are just my $0.02 on how fluid systems work...please do not take them as gospel.

Cheers!

Adam

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19 hours ago, Broken Anvil Distilleries said:

The recommended material options from the chiller company were industrial ABS

Wow. That's brutal.  From a performance perspective I am aware of no reason not to go with PVC compared to ABS.  I can't imagine the cost of doing our in copper. Ouch!

 

 

 

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  • 1 month later...

Typical Chillers as used in Breweries etc. are generally not considered " closed  loop " but rather " open loop " because the return well is vented and at atmospheric pressure.

If your piping is not too far fetched air eliminators are not needed on this type of system. Check valves and anti backflow sytems are mainly to prevent loss of glycol from overflow back to the return well when the system loop pump is shut down. This is generally only ever an issue if you have a lot of vertical rise coming away from your chiller and it is volume dependent relative to the piping that must equalize. All kinds of people run glycol in PVC successfully, but I do not advise it for distillation as its possible for the temperatures on the return line to exceed the limit of that type of pipe. Its is possible to run straight glycol without a secondary glycol to water HX system if the chiller and return well are upsized. There are both advantages and disadvantages to both types of system.

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  • 3 years later...

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