[AdvanSuper]

Pump starts up fast and then slows down. I just started to move my whole setup to a new case... I filled up the loop with water started the leak test and noticed the pump would run fast and then slow down once being turned on. Pump was working fine as of 12 PM this afternoon and all weekend as I left the PC folding.

I just realized I had the pump on it's side while I was test fitting tubing in my case... Could that have killed the pump? It shouldn't have affected it since I'm sure when it's delivered or in transit it gets tossed around and it wasn't running or had water in it... I'm a bit stumped at the moment...

 

[charliehorse55]

Have you ever run the pump dry? That is, without water flowing through the pump? Running your pump without a load will cause it to destroy itself in a matter of seconds.

 

[AdvanSuper]

Nope liquid was in the loop and pump.

 

[AdvanSuper]

I think this is my issue... Once air bubbles go through the loop at this section it's hard for them to escape through the fill port...

 

[charliehorse55]

That isn't the best fillport position, but may I ask what are your pump RPMs? What is the highest RPM you see achieved, and what value does it settle onto later?

 

[AdvanSuper]

Seems to be fine now... I never had this issue before because I used a regular Y fitting for the fillport and rad outlet with a bit more tubing. Pump is running just like before I guess it was just the huge air bubbles causing the pump to slow down and getting me worried.

I'll plug the pump into the mobo fan header and see what the RPM's are though. What's the normal operating RPM?

 

[charliehorse55]

Around 4400 RPM i think. My motherboard isn't reading the RPM on my pump some odd reason, although I have it undervolted at 10v anyways so I don't know how much help the value would be anyways.

 

[bmaverick]

If you have trouble with air bubbles often using any of the MCP35X pumps, add a little PG (propylene glycol) to the mixture. This will allow the impeller and the white bearing in the pump to be lubricated. I run my coolant mixture as 80%distilled water and 20%propylene glycol.

 

[AdvanSuper]

I just have tiny air bubbles left at this point.

 

[bmaverick]

Quote:

Originally Posted by AdvanSuper I just have tiny air bubbles left at this point.

Great then, in time those will find a place in the loop form a larger single bubble that you can burp it out later.

 

[H4rd5tyl3]

Quote:

Originally Posted by charliehorse55 Have you ever run the pump dry? That is, without water flowing through the pump? Running your pump without a load will cause it to destroy itself in a matter of seconds.

when I finished my loop I turned it on to check for leaks and If I remember correctly water was getting stuck right before the pump, so I think my pump was running dry for a bit? Could this have affected my pump at all? I have a Danger Den / Laing DDC-12V Center Inlet 18 Watt Version 3.2 pump. As my fillport comes down from the top of my case to the res which is in between the top and middle of my case, is that a decent position?

 

[charliehorse55]

Quote:

Originally Posted by H4rd5tyl3 when I finished my loop I turned it on to check for leaks and If I remember correctly water was getting stuck right before the pump, so I think my pump was running dry for a bit? Could this have affected my pump at all? I have a Danger Den / Laing DDC-12V Center Inlet 18 Watt Version 3.2 pump. As my fillport comes down from the top of my case to the res which is in between the top and middle of my case, is that a decent position?

It might have, although I doubt it. You have to run the pump dry for around 10 seconds before it starts to do permanent damage to itself.

 

[H4rd5tyl3]

Is there a way to check if there is damage to the pump without taking the whole loop apart?

More pump info: A spherically suspended rotor/impeller rests on top of a ceramic ball and is driven magnetically, thereby eliminating the need for a shaft motor connection. The pump lasts longer, consumes less power and offers superior performance characteristics when compared to other pumps in its class.

 

[charliehorse55]

Hook the RPM header up to your motherboard. For 350 pumps the reading should be 3800 rpm and the 355 should have a rating around 4400 RPM.

 

[bmaverick]

Quote:

Originally Posted by H4rd5tyl3 Is there a way to check if there is damage to the pump without taking the whole loop apart? More pump info: A spherically suspended rotor/impeller rests on top of a ceramic ball and is driven magnetically, thereby eliminating the need for a shaft motor connection. The pump lasts longer, consumes less power and offers superior performance characteristics when compared to other pumps in its class.

Per your manufacture quote, yes the rotor/impeller sits well on the ceramic ball. The impeller plastic is a Nylon 6/6 material that has four spherical flanges that ride upon the ceramic ball. If the pump is run dry, those four flanges heat up and become deformed. Thus a non-functional pump. All one would need to do is replace the rotor-impeller to make the pump work again.

If Laing were to ever change their material for the plastic impeller to Delrin 500P (coefficient of friction is 0.2 for those of you who care with thermal stability) it would be the best improvement ever. Then you could run the pump dry easily for an hour.

As for now, the only thing to help a pump run dry for a longer period is to take the pump apart add one or two drops of 3in1 oil to the four spherical flanges, reassemble the pump, place the pump in your loop and try your loop. (DO NOT use WD-40 spray nor any silicon lubricant!!!) The oil will lubricate the surfaces for a short time and revitalize the plastic flanges.

 

[H4rd5tyl3]

Thanks for that. I'm thinking of returning this pump and getting a MCP355 or 655. I heard the 355 is a bit louder though. Is it worth doing this? I stil ldon't know yet if my pump is dead, need to check it in a bit.

 

[charliehorse55]

Quote:

Originally Posted by H4rd5tyl3 Thanks for that. I'm thinking of returning this pump and getting a MCP355 or 655. I heard the 355 is a bit louder though. Is it worth doing this? I stil ldon't know yet if my pump is dead, need to check it in a bit.

A 355 is semi-loud without an aftermarket top, but with one it is only as loud as a 800-1000 RPM fan.

 

[H4rd5tyl3]

I have the XSPC acetal top for it. Aso, I noticed PerformancePCs has the same exact compression fittings by bitspower i'm looking for but it says it's for tygon tubing, compared to FrozenCPU who has them for about double the price but it doesn't say anything about tygon tubing. So my question is would the one that says "for tygon tubing" be compatable with regular tubing?

 

[charliehorse55]

Quote:

Originally Posted by H4rd5tyl3 I have the XSPC acetal top for it. Aso, I noticed PerformancePCs has the same exact compression fittings by bitspower i'm looking for but it says it's for tygon tubing, compared to FrozenCPU who has them for about double the price but it doesn't say anything about tygon tubing. So my question is would the one that says "for tygon tubing" be compatable with regular tubing?

Yes, that is just marketing at work. A fitting is compatible with tubing based on the size, not brand.

EDIT: Kind of like how some PSUs are "SLI Ready" but in reality they will work for SLI or Crossfire.

 

[H4rd5tyl3]

Gotcha, thanks again charlie.