2 pumps in parallel

[Stickman]

Is there any known disadvantages to running two identical watercooling pumps in parallel to get a higher overall flow rate on a watercooling loop?

(I'm trusting that my meaning is clear here: I mean parallel in the same way it's used in electronics when two components are used side by side... so you spit the single loop into two before the pumps, and combine again afterwards)

Thanks.

 

[twist3d0n3]

you'd probably get better results from having it in series, but spaced out throughout the loop.

for example, in my gf's pc, i've set it up as such:

res - pump - pump - rad - mosfet - mosfet - cpu - nb - rad - gpu1 - gpu2 - sb - res

but i have a feeling it'd be much better doing this:

res - pump - rad - mosfet - mosfet - cpu - pump - nb - rad - gpu1 - gpu2 - sb - res

 

[Tikkabhuna]

you'd probably get better results from having it in series, but spaced out throughout the loop.

for example, in my gf's pc, i've set it up as such:

res - pump - pump - rad - mosfet - mosfet - cpu - nb - rad - gpu1 - gpu2 - sb - res

but i have a feeling it'd be much better doing this:

res - pump - rad - mosfet - mosfet - cpu - pump - nb - rad - gpu1 - gpu2 - sb - res

This sounds right. Although my reasoning for this is that in racing games speed boosts work a lot better getting two separated out rather than one after another.

 

[Squakingcow]

If you have two pumps in parallel the pressure will remain the same but the flow rate will double (in a loop with no restriction, so this will never happen in a 'real' loop) and having the pumps in series will increase the head pressure.

Since most water cooling set-ups tend to be pretty restrictive, there would be little to no advantage to running the pumps in parallel, however the increase in pressure from running the pumps in series could provide a noticeable difference in cooling performance. In theory the placement of the second pump should make no difference since water cooling set-ups run in a closed loop.

 

[JonJ678]

In practice though when i ran two in series, with a few blocks between them, the length of tubing before a pump pulled flat and bad things happened to temperatures. The loop isnt sealed, the pumps arent identical and apparently they set up a pressure difference in the loop.

The literature strongly suggests that using centrifugal pumps in series, adjacent, is common practice.

I think parallel would encourage cavitation, but thats just a hunch.

 

[Squakingcow]

Well the pumps are kind of like a battery in an electrical circuit, the water moves around the loop due to a pressure difference on the inlet and outlets of the pump. So since running two pumps in series increases the pressure difference there will be a greater negative pressure on the inlet side of the pump, so yes if you have weak/soft tubing it is possible that it could collapse.

IIRC when there was a fad for RD30s a couple of years back when running them at full whack there were quite a few issues with tubing flattening on the inlet.

 

[JonJ678]

Perhaps. Ill have a think about that one. No flat tubing now that theyre next to each other.

Its 11/8mm tygon in my case, which might count as soft