Dual D5s - Configuration and failover questions

[WantoN]

Hello chaps,
I've never run dual pumps, I won't bore you with my plans just yet, just want to ask some advice for the planning phase.

1) With a series pump top, would a pump failure still allow the other D5 to run well?

Would the weight of the other impeller / jammed impeller cause significant wear / issues?

2) Has anyone run a valved setup for Dual D5s? I'm thinking having a few ball valves to switch from series to parallel, effectively removing a pump from the loop in the event of failure.

3) I'd rather run a single large reservoir for both pumps. Any issues with this?

4) Just want to confirm my assumption that with D5s series config is best, to give additional head pressure?

5) I'm considering AquaSuite. Can someone confirm that I can use a flow sensor and speed signal (from a dead pump) for failover? ie automatically modify the pwm signal to the remaining good pump?

 

[ubersonic]

Basically with dual pumps, series will double up on head pressure and flowrate will remain the same (aside from any increase seen from the additional pressure overpowering any restrictions), parallel will double up on flow rate and head pressure will remain the same.

1) If a D5 pump fails in series then the loop will simply appear like it's just a single pump loop and the impeller of the dead pump will spin in the flow (the D5 uses a magnetic impeller, it's not physically connected to a motor via a shaft or anything so it's nigh on impossible to seize one). If one fails in parallel then it will again act like a single pump loop and the flow through the dead pump will be pretty non-existent.

2) I've never seen that done, but you could if you wanted, I'm guessing you want to be able to remove a pump without draining the loop?

3) No, that's the way you should do it. Multiple reservoirs in a single loop is generally a bad idea unless they are in parallel (which is a lot of work for no real benefit aside from looks), as with serial reservoirs you're basically pumping one res into another and it is actually possible to raise the level in the one downstream.

4) It depends what you want TBH, do you need pressure or flow? I've run both over the years, generally speaking with a modern loop flow isn't as important as it was in the old days. My current setup runs serial D5 Varios both set to 1/5 speed, because two at 1/5 is more powerful than one at 2/5 and quieter.

 

[pingu666]

if you have them parrell and one isnt working, you can get backflow? i had 2 submerged ehiem pumps joining with a Y connector, run 1 pump and the water takes the easiest path... which is around the Y and back out the dead pump.

 

[Mcnumpty2323]

Can answer the first bit
I have two pumps in series
For redundancy
Tested with simulated pump
Failure and it ran perfectly
Well with a fairly complex loop

 

[WantoN]

Thanks chaps, confirmed everything for me.

My current setup has quite a few 90s, the D5 does fine. But I'm building a new larger build with some additional blocks, and I wanted to fit a second pump because a) pump downtime is extremely annoying, and b) I'd rather have two pumps running as quietly as possible.

I'm sick of scraped knuckles, hard to access ports and a VRM heatsink that can't be utilised. New build will make use of the QDCs, larger rads etc that I have knocking about.

I'm not too concerned about valving if the dead pump would add little restriction.

 

[Mcnumpty2323]

I used quick disconnects
In my latest build
Makes life way easier
If want to change cpu, gpu, pump
Can take them out
No draining required

 

[WantoN]

I used quick disconnects
In my latest build
Makes life way easier
If want to change cpu, gpu, pump
Can take them out
No draining required

Which ones did you use? I have a load of Thermal take ones, but they're so difficult to disconnect.

I suppose the restriction they add wouldn't matter with the additional head pressure of two D5s?

 

[Mcnumpty2323]

Which ones did you use? I have a load of Thermal take ones, but they're so difficult to disconnect.

I suppose the restriction they add wouldn't matter with the additional head pressure of two D5s?

Think they are
Koolance vl3 if I remember
Correctly and didn't notice any
Flow restrictions
Though not using a flow meter
Just going by eye and temps