Pumps In Series & Parallel

[EHW Ai]

Since I need to do a full tear down to get rid of the XTR crap, it's time for my nearly anual redo of my loop. Right now I'm running 6 D5 Next's in series. My question is am I better off this way or running 4 of them in parallel and 2 in series? 

[Avacado]

2 hours ago, Outsider said:

Since I need to do a full tear down to get rid of the XTR crap, it's time for my nearly anual redo of my loop. Right now I'm running 6 D5 Next's in series. My question is am I better off this way or running 4 of them in parallel and 2 in series? 

IIRC you have plenty of flow. You are after increased head right? Only one way to find out. 

[Sir Beregond]

3 hours ago, Avacado said:

IIRC you have plenty of flow. You are after increased head right? Only one way to find out. 

Inclined to agree. I've not run multi-pump before so I am of no help here. I know some who run 2. First I am hearing about 6.

 

I know @J7SC_Orion runs multiple pumps. Trying to think who else might here.

[Fluxmaven]

Why are you wanting to change? 

 

Pumps in series increases head pressure

 

Pumps in parallel increases flow rate. 

 

I'd have to assume with 6 in series you don't have issues with flow or head anyway. I've never ran more than 3 pumps in a single loop and I always run everything in series. 

from a redundancy standpoint, series is nice because a pump dies, no big deal the others pick up the slack. In parallel depending on how it's plumbed I'd think you have the chance of weird stuff happening since the water is just gonna take the path of least resistance. 

[J7SC_Orion]

4 hours ago, Sir Beregond said:

Inclined to agree. I've not run multi-pump before so I am of no help here. I know some who run 2. First I am hearing about 6.

 

I know @J7SC_Orion runs multiple pumps. Trying to think who else might here.

 

...I've run up to 5x D5 in series, but that was for a dual HEDT / mobo system with a total of 8x GPUs back in the day. In my applications, 2x D5s in series give you the best balance (and I never run less than 2x D5s for other technical reasons). 3x D5s start to get a bit tricky to bleed and synchronize but are doable. It is probably better to have separate loops with 2x D5s per, unless there massive head pressure is needed...

[Sir Beregond]

1 hour ago, J7SC_Orion said:

 

...I've run up to 5x D5 in series, but that was for a dual HEDT / mobo system with a total of 8x GPUs back in the day. In my applications, 2x D5s in series give you the best balance (and I never run less than 2x D5s for other technical reasons). 3x D5s start to get a bit tricky to bleed and synchronize but are doable. It is probably better to have separate loops with 2x D5s per, unless there massive head pressure is needed...

You know I never even thought of the filling and bleeding aspect of multi-pump systems. Thanks for putting that in my mind in case I ever do one in the future.

[EHW Ai]

I get around 1.5GPM with all at max and 0.6GPM with all at 25%. I'm looking for more flow since I should have more then enough head no matter the setup I use so I'm trying to see if I can get 2GPM or more at lower RPM's.

 

My loop runs Pump/Res to Pumps/res then to a pair of dual top D5's. I got 5 pairs of QDC4's and most if not all pump inlet/outlets are gimped with 90's. I'm looking for more flow, I should have more then enough head