Odd plumbing problem

d2mini

Premium Member
I don't really need my chiller running yet but wanted to get it plumbed in to the new build while i was doing everything else. But I'm having a weird problem, that I am thinking may have to do with physics that I just don't understand but wanted to run it by joo guyzzz. ;)

So in the past I always had my chiller fed by a Tee off the return line.
Then the output line from the chiller emptied back to the sump.
This time I was trying to make the plumbing a little cleaner so what I did was install a Y fitting on the return line right after the pump. Ran a short length of plumbing to the chiller. Then I ran a short length of plumbing from the chiller's output into another Y maybe 2 feet from the first Y.

So it's basically like being on the freeway, merging off on to the feeder road for a minute, then merging back on to the freeway on the very next entrance ramp. :D

My problem is that i can see through a small piece of clear tubing at the chiller that very little water is flowing through, like next to nothing. So I'm assuming that something about the way i have it plumbed is creating some kind of restriction, or for some reason the water just doesn't want to flow through that first Y into the chiller?

Any ideas?
I was really trying to avoid having a whole other line of pvc running all the way back to my sump. I thought getting the water back into the return line would be a lot cleaner and it would go right back to the display tank.
 

d2mini

Premium Member
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woodnaquanut

Premium Member
Water doesn't act exactly like cars on the freeway. There is back pressure on the water so the 'merge' back on is resisting the flow. Not to stretch the analogy too far but in your case the onramp metering lights are on! :)

Best to daylight the chiller output and go back to the sump like you did before.
 

d2mini

Premium Member
ok, this is what I figured, i'm just staring at it and wondering WHY.
Couldn't get the why to make sense in my head, even though i somehow knew that must be the problem. :lol:

Darn it. More money going to home depot and lowe's bank account.
 

sleepydoc

Team RC
Yup - water follows pressure. The pressure difference between the inlet wye and the return wye is minimal and there will be some pressure drop in the chiller circuit due to the pipe resistance, thus no flow. If you're on the freeway and you could keep going at 55 MPH or take an exit and get back on, which would you do? :)

Putting a valve between the fittings like Kuch suggested makes the resistance and thus pressure drop going up the return pipe much greater and so the chiller becomes the path of lower resistance.

It's kind of like putting an accident on the freeway between the exit ramp and the entrance ramp and forcing all the cars to take the exit because only one lane is open on the freeway.
 

d2mini

Premium Member
Ok, but which would be the better solution if I wanted to keep the overall resistance of all the plumbing down? That's a Barracuda Gold pump and I just ordered the Hammerhead impeller because I need more flow! :)
 

woodnaquanut

Premium Member
I think if you shut down the main return flow enough to get more chiller flow you will kill total flow.

Sure it will go thru the chiller but that plumbing is most likely much smaller, thus less overall total flow.

For max return flow, give the chiller it's own pump.
 

sleepydoc

Team RC
+1
If you're already worried about flow you should put it on it's own pump. Heck you could even plumb it completely separate. Fewer fittings on the return line will mean less head pressure.
 
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