MCP355 Overspeed shutdown?

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lapoltbaCT

n00b
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Jun 10, 2012
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So... I was bleeding my loop today after replacing a burned out MCP355. It's basically the same setup I had. Just the pump with a T-line on the inlet, cpu block, to the radiator.

I partially filled the loop as best I could by adding water, rolling the case around and repeating. I kept the T-line open and topped off while cycling the pump on and off a few times to get the water flowing.

Now, i've still got some air bubbles, but it pumps well for about 20 seconds and then shuts down. I can hear it trying to restart but nothing happens.

I was wondering if there was some sort of over-speed shutdown on these to protect them from running dry?
 
Anyone?

I had already ordered 2 of the 18w repair kits, one to fix my other pump that burned out on me. I guess i'll probably pull this one apart and possibly replace it too. It really seems like the board overheats quickly and shuts down.
 
pics of your setup please.

Don't know about any safety mechanism inside the pump. BTW Is your PSU heavily loaded?
Try testing only the pump with a water reservoir directly on top of it.
 
I don't have any experience with the 355 since i prefer the D5 but i do not believe i have seen any pump with a safety feature where it will shut down with no load. Other side of that is I have seen pumps outside of the PC realm that specify that it should never run dry. As leSLIe said a pic of your setup would help in solving this puzzle.
 
The pump was the only thing on the PSU since I was bleeding the system. I did the PCB swap today on both pumps.

The "new" one that I bought to replace the one that I knew burned up is now working flawlessly. I'm pretty sure the board on that one was bad somehow. I soldered the windings on the other one wrong but haven't fixed it yet.

Got the pump installed and i'm currently running it to get some of the fine bubbles out and make sure my compression fittings will hold. Damn that pump moves alot of water... Oh, and it seems to get pretty hot compared to the stock pump, i can only assume it is ok and the result of more current/better flow/higher driving power of the PWM chip.

I'm using the Tygon 3603 tubing 1/2x5/8 and it expands a ton when the pump is switched on. So much that my t-line drops by a few inches. :eek:

Pic below of the setup. Ignore all the wires, they are going away once I button everything back up. I spent a bunch of time on this case doing cable management and I think it came out pretty well.

 
Glad it's back up and running. I have never seen a board go bad on a pump but anything is possible.
 
When I bleed my loop I use an old HX850 hotwired outside my case with only the pump on it and it doesn't like being turned on and off with such a small load.
I get around it by waiting a few minutes between cycles.

Probably only works that way cos of capacitors getting overloaded and needing to drain.

I thought that might have been your problem but you have clearly found your solution.
Good stuff!
 
Thanks. I figured while I had the two pumps apart it was a worthwhile upgrade to swap the boards in both. Seems to be a huge improvement in power and I like the fact that the pump is controlled by a single chip.

I haven't had a chance to hook it up and do a burn in on the thermal compound yet, been too busy with work to do much.

I had really good luck OCing this particular 2600k, not even really knowing what i was doing. I pushed 3.7Ghz without much difficulty or voltage. My pump setup and lack of a good pair of fans for the radiator were my limiting factors. I look forward to seeing what it will do with some proper cooling.
 
I'm using the Tygon 3603 tubing 1/2x5/8 and it expands a ton when the pump is switched on. So much that my t-line drops by a few inches
Click to expand...

what do you mean exactly? that pump shouldnt be able to put out any amount of pressure enough to make the tubing expand... even if you were to block the flow completely while the pump was running, it would only build up a few PSI at the very most.
 
Well, at 12V and looking at the pump curve for the modded pump, it puts out up to 9 PSI at 1.5 GPM. I haven't measured the flow in my loop, but all that is there is the EK Supreme HF with the low restriction plate and a 2x120 radiator.

The tubing is very soft and it doesn't take much to make the tubing expand a bit. Even if it is just straightening out the bends some, it will expand.
 
lapoltbaCT said:
Well, at 12V and looking at the pump curve for the modded pump, it puts out up to 9 PSI at 1.5 GPM. I haven't measured the flow in my loop, but all that is there is the EK Supreme HF with the low restriction plate and a 2x120 radiator.

The tubing is very soft and it doesn't take much to make the tubing expand a bit. Even if it is just straightening out the bends some, it will expand.
Click to expand...

Sounds to me more like you still have not completely bled your loop. The little pumps used in this hobby are not powerful enough to cause tubing to noticeably expand or contract.

In fact just looking at your set up, your radiator probably has a huge air pocket in its tank.

You should flip the radiator around so that the inlet/outlet side is facing up.
 
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