Another CSP-750 failure
 

My CSP-750 that I've had runninga couple months in my system now failed. Apparently the shaft seal failed as the coolant leaked into the motor cavity and then slowly out of the case through where the wires come in. The motor finally died. Ah well, time to order a DDC.

and I really DID try to resist . . . . .

was this the 50,000 hr MTBF motor ?

was this the 50,000 hr MTBF motor ?

maybe but not under water apparently, rofl

:D rotfl

shame relly, was it the rev.1? (blue one)

Sorry but that pump is designed for failure. I expressed my reservation about the mechanical seal, as did others in the forum. This is a bad bag for our German friends.

http://www.webshop-innovatek.de/images/csp7501_150.jpg

It was a Rev 2 pump, I have a second one I put in the machine and we'll see how long it lasts. already ordered a couple DDC's

Ah yes, and where is hotseat in all this mess, his name is quite fitting

I wonder if they tested these pumps under load, or just in their chamber freeflowing. Im willing to bet just freeflow.

it is an easy trap to fall into, been there

I've been thinking about the shaft seal leakage and it seems likely that this could be a result of the system being sealed with little to no air expansion space to accomadate pressure changes from thermal expansion. There could be significant pressure deltas between the system and atmospheric pressure. C-Systems may have only been working with vented systems. Including an expansion space in the system may be a possible work around.
Looking forward to getting my DDC's though so I can stop worrying about this aspect.

Well both of mine are sounding like they're on their way to the junkyard. That's why I replumbmed the loop with the old l35 until a pair of DDC's arrives. This is the firt and the last time I've looked at C-Systems.

Your vinyl hoses provide enough resilience to limit pressure increase due to thermal expansion.

The thermal expansion coefficient of vinyl hoses is: 70-250 (x10-6 °C-1) from efunda.com

Thermal expansion of water is about: 2-5 (x10-4 °C-1) -From 20-60°C from efunda.com

The vinyl expansion could cancel the thermal expansion of the water (or create a negative pressure).
You would have to estimate volumes and lengths and consider the tubing geometry (Circumference and length vs volume expansion).

Was your motor rusted like mine was?

There was a small amount of corrosion starting on the rotor hub, but nothing major. The most intense corrosion was on one of the coils inside the motor, probably on the downhill side of the drip from the shaft.

I'm not convinced that just because vinyl has a larger coefficient of expansion than water that you won't get pressure deltas from the temperature swings. A good portion of the water is in the radiator and blocks, and any air in the system will have a large expansion coefficient. Without actually measuring the pressures I would hesitate to jump to conclusions one way or another. I merely brought up the concept that a closed system without a vent to atmospheric pressure may generate pressures on the shaft seal that exceed it's design limits.

I vented my system and am running that second CSP750 pump in there, but it started out making rude noises when I first turned it on so I doubt I'll get any usefull information out of this whether it fails or not. Besides I doubt I'll be able to put up with the noise for long enough, especially when my DDCs arrive tomorrow.

Glad I did not wait for one of these pumps. If they had been in stock at Dtek I would have ordered it. Instead got the AquaXtreme 50Z-DC12 and have been very very please. This baby really moves some water and yet is very queit. I cannot hear it over the sound of the water swishing into the res.

New model - CSP-MAG
 

Looks like they've decide to eliminate the shaft seal
and go to an in-fluid bearing.

http://www.c-systems.ca/mag.html

Also going to have two impeller designs, High Flow and High Pressure..
Hope they ship soon and pH can get some in for testing.

Mine has been running strong cince they came out when I preordered mine from d-tek.

I originally made my own impeller housing to use my own hosebarbs because they wouldnt go all the way in it.

Jon