Go Back   Hardware Canucks > CASES & COOLING > Water Cooling

    
Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old September 16, 2009, 08:48 AM
Rookie
 
Join Date: Aug 2009
Location: Santa Cruz, Ca
Posts: 15
Default Adding pump question

Was thinking of adding a second pump D5, to my loop to increase flow, right now my loop goes;

res-->pump-->rad-->rad-->cpu-->gpu-->gpu-->back to res. If I add the second pump after second res so the loop would be

res-->pump-->rad-->rad-->pump-->cpu-->gpu-->gpu-->back to res, would that be the best way to utilizes the second pump?

Any suggestions would be greatly appreciated, thx

Here's a pic of my rig in its current state.

__________________
▀olweval

Browser: Intel QX9650 (3.0GHz) | Noctua NH-C12P R | Asus P5E3 Deluxe | 4GB Corsair Dominator DDR3 SDRAM 1800 | MSI 8800 GT | Customized Antec Super Lan Boy | Antec Signature SG850 PSU | Ubuntu x64 9.04

Gamer: Intel i7 920 (2.66) @ 3.6 | Water Cooled Buy Swiftech | ASUS Rampage 2 Gene | 6GB Corsair Dominator 1866 GT's | 2xGTX 280's | Banchetto 101 Bench Table | Antec Signature SG850 PSU | Windows 7 RC1 x64 Ultimate
Reply With Quote
  #2 (permalink)  
Old September 20, 2009, 10:24 PM
Rookie
 
Join Date: Sep 2009
Posts: 40
Default

Nice looking build you have there! Looks very cool...

I think in the configuration you are running it's a good place to put the second pump. I have not tried it but would think the perfect spot for a second pump would be after the most restrictive block in your loop. That way you could pump up the pressure with the second pump after it has dropped off going through the restriction. It should increase the overall efficiency of the loop giving you more flow.
Have not tested this theory but may just try it out before I put my next build together.

John
Reply With Quote
  #3 (permalink)  
Old September 20, 2009, 11:11 PM
sswilson's Avatar
Moderator
F@H
 
Join Date: Dec 2006
Location: Moncton NB
Posts: 14,496

My System Specs

Default

I get differing opinions on this but have yet to actually see a dual pump loop in action.

My concern with dual pumps in series is that unless they are perfectly matched for flow is that one part of the loop would have a tendancy to empty the other part of the loop.
__________________
MSI Z87I Gaming AC / i5 4670K / 2X 4G Gskill 1866 DDR3 / XFX XTR 750 / EVGA GTX 680 SC+ 2GB / Intel DC S3700 200G / random 160G Sata HDD
Inwin 904 / Swiftech MCP655-b / Alphacool NexXxos XT45 120 Rad / 2X Scythe GT AP-15 / EK Supreme HF / Dell UltraSharp U2412M

Asrock AM1H-ITX / AM1 Athlon 5350 / 2X4G Gskill PC3-14900 / Intel 6235 Wi-Fi / 90W Targus Power Brick / 320G Seagate Momentus / Mini-Box M350 / 1X 22" Dell IPS / 1X 22" HP
Reply With Quote
  #4 (permalink)  
Old September 21, 2009, 01:49 PM
Rookie
 
Join Date: Sep 2009
Posts: 40
Default

Quote:
Originally Posted by sswilson View Post
I get differing opinions on this but have yet to actually see a dual pump loop in action.

My concern with dual pumps in series is that unless they are perfectly matched for flow is that one part of the loop would have a tendancy to empty the other part of the loop.
You are bound to get conflicting opinions, as it quite difficult to actually calculate flows and pressures for such an arrangement.
The pumps do not have to be perfectly matched as each pump has its own inlet/outlet performance curve. If you stay within the curve you won't hurt the pumps and most of the pumps we use have a fairly large performance curve.
Personally I'm not sold on the idea of pumps in series as I just can't see where it is needed from a performance stand point. As a redundant pump yes, performance no.
Reply With Quote
  #5 (permalink)  
Old September 21, 2009, 03:19 PM
MpG's Avatar
MpG MpG is online now
Hall Of Fame
 
Join Date: Aug 2007
Location: Kitchener, ON
Posts: 3,143
Default

Hmm, never noticed this post earlier for some reason...

Firstly, if you're looking for temperature miracles, I wouldn't get your hopes up. My own testing on the GTZ (with no other blocks in the loop) has been showing a grand total of about 1-1.5 degrees difference between one and three MCP355's running in series. With its higher heat dump, the MCP655 certainly isn't going to do any better.

Generally speaking, unless it's a serious mismatch between pumps, watercooling systems are fine as long as the loop is fully bled, as hydrostatic pressure keeps the pumps from starving each other.

A quick test you might want to try with your first pump: Do a temperature run, and see what temps you get. Turn the pump speed down one notch, and do it again. Turn it down another notch and repeat. If the temperatures aren't getting worse when slowing things down a little, the behaviour of flow/temperature curves make it almost a certain bet that temps won't get any better when speeding things up.

If you decide to go for a second pump anyway:

The position of the second pump is 99% irrelevant. The only thing to watch out for is when first bleeding a dual-pump loop - MCP655's can't be run dry, so only use the first pump until most of the air is bled out of the system. Also keep an eye on the reservoir, since running two pumps will lower the liquid level quite a bit, possibly below the plastic deflector shield. So if you top up the reservoir, and then turn the pumps off, all that water will try to return to (and overflow) the reservoir - make sure you fully tighten the cap first, and listen for a quiet hissing to warn you if the cap seal isn't perfect. Conversely, when the pumps are running, keep the cap open at least a little, as multiple pumps can actually give you vacuum/pressure problems that make it harder for the loop to bleed properly.
__________________
i7 2600K | ASUS Maximus IV GENE-Z | 580GTX | Corsair DDR3-2133
Reply With Quote
  #6 (permalink)  
Old September 21, 2009, 04:00 PM
Hall Of Fame
F@H
 
Join Date: May 2008
Location: London
Posts: 1,411

My System Specs

Default

^ Agreed, try lowering your current pump speed and see if anything changes. I don't think you're going to get too much of a difference.
Reply With Quote
  #7 (permalink)  
Old September 21, 2009, 09:27 PM
Dazmode's Avatar
Hall Of Fame
 
Join Date: Mar 2009
Location: Oakville
Posts: 1,695
Default

Nice setup!
__________________
Venom Build: Caselabs SMH10, 3930k, 2x GTX680, MSI BigBangII, 8x Dominators, 2 x D5 , Quad Rad, Adaptec 7805, 4x WD Red, 2x Intel 510, Aquaero 5, 11x GT
Silent Sniper Build: Final Video, XSPC H1 Cube case, Supreme HF, 2xGTX470, GA G1 Sniper, Dominators, 2x Triple rad, Triebwerk Fans, 2x D5, Custom Sleeving
Orange Build: Final Video
HTPC Build: Final Video
Reply With Quote
  #8 (permalink)  
Old September 23, 2009, 11:19 PM
biff's Avatar
Hall Of Fame
F@H
 
Join Date: Jan 2008
Location: Courtice, Ont.
Posts: 1,235
Default

I agree with a lot of what MpG says. People seem to get way to carried away with some WC equipment. Sure there will be benefits to bigger pumps and giant rads with screaming fans and solid silver water blocks (and to some that may be what they are after) but if you have a loop built with decent components to begin with then the added benefits of said equipment only drop the temps a degree or two and what does that really get you?

Since you have two rads and are considering a second pump why don't you split the loops and run a loop for the CPU that doesn't generate a whole lot of heat on it's own and is temperature sensitive, and then have a loop for the GPU's that do generate a lot of heat but are also a lot more tolerant of it.
__________________
Q6600 @ 3.83GHz w/ D-Tek Fusion
Asus P5Q-PRO
2x 2GB PC8000 Mushkin Redlines @ 1020MHz w/5-5-5-12 timings
EVGA GTX 280 (SC?)
OCZ Gamer Xtreme 600W PSU
Cooler Master Cosmos on water
Reply With Quote
Reply


Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Adding a second card to my loop? nasrott Water Cooling 10 July 15, 2009 07:04 AM
Adding blocks? Fudd Rucker Water Cooling 11 July 8, 2009 07:42 PM
Pump: Danger Den DDCPX-PRO Question Poison Ivy Water Cooling 9 October 24, 2008 11:55 AM
Pump Question lcdguy Water Cooling 10 February 19, 2008 07:58 PM