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Arnoldus
08-14-2014, 08:06 AM
Howdy,
Got a bit of an issue. I have two tanks that don't seem to want to stay cold. They happen to be the last two tanks in my loop.
I can force them down if they are they only ones needing chilling, but as soon as I throw the other tanks online, they just stop.
I notice though, that the return line on the tanks seem to have great pressure unfortunately going the wrong way, but the supply lines don't do anything. I can literally take the supply line off the tanks and no glycol comes through.....frustrating.
Any ideas?
Air in the lines? If so, why does it seem to affect only the last two?

beerguy1
08-14-2014, 08:38 AM
MY initial thought was air in the lines. YOu should have air bleeders on a high point furthest from the pump. If so open them and see if you get air out. Another thought is does the pump that you have circulating the glycol have enough HP to move that much glycol. Are any of your valves plugged (doubtful). I am leaning on a pump issue just because you can shut off the other tanks and it flows

CHeers

Starcat
08-14-2014, 07:05 PM
Air eliminators are only really helpful on " closed " loops.
Glycol systems are " open " loop.
ON a properly installed glycol system air eliminators should not be necessary as the main well it at atmospheric pressure.
Based on your symptoms you've got a pump or configuration problem going on.

You need a gauge just beyond the pump discharge so you have an idea what your baseline is when the system is running correctly.
You need a wye strainer somewhere in the system if not at each control valve.
You need to know that your mechanical seal is solid and the pump is not full of crud or sucking wind.
If the system performed originally, then you most likely have a pump problem.
If the system was always questionable you have a design problem.
Correctly installed glycol systems will not " air lock."
Air lock is common on closed loops and otherwise problematic loops that are not set up correctly.
Open well glycol systems are dirt simple compared to Multi Story HVAC closed loops.