Need a lil help with pumps in series...

[Bugsmasher]

I am currently looking at upgrading my setup from a single Hydor L35 (nice pump, its moving to my second system) to most probably an MCP600 pump with the option of adding a second in series down the road a bit per Cathars rather nice results of dual 600s @ 13.8 volts.

This is where my confusion sets in....

To add a second pump in 'series' do they need to be adjacent in the cooling loop or would it make more sense to have them separated by a waterblock(s) or heater core?

Which solution if either would work better?

A. Pump1>>Heater Core>>Pump2>>Waterblock(s)
B. Pump1>>Pump2>>Heater Core>>Waterblock(s)

Would there truly be any difference?

The primary reasons for considering running 2 pumps in series are twofold- first I would have a 'backup' in case one pump failed to start. Second (and the lesser of the two reasons) would be the performance increase. I was also planning on adding a 13.8vdc 4amp power supply in order to power these pumps without hitting my primary system power supply.

[CoolROD]

If you have a closed system it makes little difference where your pumps are located in the loop.

Redundant pumps means twice the likelyhood of a pump failure.

[nikhsub1]

Originally Posted by CoolROD

Redundant pumps means twice the likelyhood of a pump failure.

And twice the redundency

[Bugsmasher]

Thanks for the response.

Now onto the question that the answer brought up. Since there are indeed two pumps there will indeed be twice the chance of a failure of a single pump. This said in a system with two of these pumps with one that has failed the second pump will indeed still create flow correct?

How restrictive would a failed pump be in this situation? More restrictive than a waterblock?

[CoolROD]

I am not familiar enough with the MCP600 to make that call. Many centrifugal pumps free flow easily...someone else here may know. Bill has done enough work with these that I bet he knows...

It could be hard to tell if a pump is not running when two are in series...just a thought.

These ideas (and your original questions) are acutally pretty common here and all have been answered extensively in varoius threads.

[Bugsmasher]

Yeah, I have read alot of the threads about series vs parallel and also found a fair amount of threads about single pump loop layouts. Unfortunately what I hadnt found so far was anything regarding the actual layout of a dual pump loop.

It is indeed a closed loop so in all honestly logic tells me that the order really shouldnt matter since there really is no 'slowing' of the overall flow in the loop. I am simply having a hard time getting my mind to grasp the fact that by placing a pump on each side of the most restrictive portion of my loop (the waterblocks) that I wont actually achieve any noticable changes.

Thanks for the input guys

[CoolROD]

The flow through your loop is a function of the sum of the pressure drops. Order is not important.

There is some benefit from the placement of your pumps WRT motor heat: I prefer to place my pump before the radiator. Placing the pump before the W/B will give you a slightly higher water temperature entering the block (due to the pump work), but of course the water temperature in the radiator will be the same regardless.

[Output]

I placed the pump before the WB since it has the largest pressure drop, thus only one hose /part has high pressure in it. This I think will reduce the chance for leaks.

[CoolROD]

Originally Posted by Output

I placed the pump before the WB since it has the largest pressure drop, thus only one hose /part has high pressure in it. This I think will reduce the chance for leaks.

That is valid and absolutely true.

I also tried to factor in easy bleeding to dictate my layout. ie: I am feeding the single pass heater core from the bottom...

Water heating from the pump work is very small (but easy to figure) and should not dictate your layout.