Is my MCP355 pump dead? EDIT: Resolved, I think

[thephew]

I would ask this on XS, but it appears to be down.

I just drained my loop to swap in a new video card. I refilled the reservoir (XSPC acrylic res top) and tried to bleed the loop by powering on the pump. However, the power supply wouldn't turn on for more than a second or two (and the pump didn't spin), then the power supply would cut itself off (I'm using a jumper between the 2 pins on the 24pin connector to simulate the power switch). The pump is the only thing attached to the power supply. I tried this with two different power supplies, same issue.

I removed the res top from the pump to inspect the impeller, and everything looks fine. The impeller rotates smoothly, but it doesn't rotate freely (there is some resistance). The motor doesn't click or bind while rotating. I measure ~6kohm across the motor with a multimeter.

Is my pump shot? Why would draining and refilling break it? Is there anything else I can check to find out?

 

[thephew]

UPDATE: I ran the pump in free air for a second, just to make sure it wasn't catching on the res top or something. Ran fine, so I put it back on the res top and added water. Didn't work at first, but then I switched which Molex connector I was using and now it works fine. So I'm thinking the connector was shorting out. I never even touched the connector during the video card swap, so I'm not sure how it could have broken.

Ug. I always have these problems that resolve themselves without me ever figuring out the source of the problem.

 

[WoodButcher]

IIRC many PSU need a 5v draw to run when jumped like that. I really don't remember exactly but if you asked in the PSU forum you may get a better answer.

 

[Rubycon]

UPDATE: I ran the pump in free air for a second, just to make sure it wasn't catching on the res top or something. Ran fine, so I put it back on the res top and added water. Didn't work at first, but then I switched which Molex connector I was using and now it works fine. So I'm thinking the connector was shorting out. I never even touched the connector during the video card swap, so I'm not sure how it could have broken.

Ug. I always have these problems that resolve themselves without me ever figuring out the source of the problem.

Never, EVER run these pumps even for an INSTANT dry! It WILL damage the bearing and shorten the lifetime of the pump. You would not start an engine dry (no oil) even if just turning it over to see if it starts either. (same reason)

Just because it works now does not mean damage was not done. I'm not kidding. These pumps have no intolerance for dry run for ANY time, period. Even if your reservoir runs low and the pump "slurps" it MUST be shut down IMMEDIATELY or the bearings will start self destructing.

 

[OVerLoRDI]

Never, EVER run these pumps even for an INSTANT dry! It WILL damage the bearing and shorten the lifetime of the pump. You would not start an engine dry (no oil) even if just turning it over to see if it starts either. (same reason)

Just because it works now does not mean damage was not done. I'm not kidding. These pumps have no intolerance for dry run for ANY time, period. Even if your reservoir runs low and the pump "slurps" it MUST be shut down IMMEDIATELY or the bearings will start self destructing.

Rubycon beat me to it.