G5 new coolant pump replacement will not work

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Level 1

8 points

G5 new coolant pump replacement will not work

Hi, I have researched the internet and found a vast amount of good help regarding the replacement of the coolant pump installed in some G5 towers. However, after installing a brand new Swiftech MCP350 coolant pump and filling the system with coolant, I can not get the pump to operate. To test it, I am using a bench power supply at 12 volts and current limited to 2 amps. I have not modified the wires from the pump at all. When I connect 12v to the yellow wire and ground to the black wire, the power supply voltage drops to 0 and the pump does nothing. Am I doing something wrong?

Mac OS X (10.5.8)

Posted on Mar 31, 2011 4:47 PM

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Answer 1

madroadbiker Author

Level 1

8 points

Apr 8, 2011 9:33 AM in response to madroadbiker

I found out what I was doing wrong. The current limiting on my power supply was the problem all along. Apparently the current required to start these pumps is quite high - on the order of 8 or so amps! So limiting the current to 2 amps like I was doing would not allow the motor enough starting current. When I removed the current limit, it started and ran just fine. Interesting enough, while it's running, it only draws about 0.7 amps which is about what the spec that comes with it says. The spec says nothing about starting current. I was so afraid of burning this thing up that I over compensated by limiting the current. Lesson learned and thought I'd pass it on.

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Answer 2

BDAqua

Level 10

239,813 points

Apr 8, 2011 11:22 AM in response to madroadbiker

Great work, thanks for the report, good to know about that starting current! 🙂

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Answer 3

romko23

Level 2

408 points

Apr 8, 2011 10:59 PM in response to madroadbiker

Hello,

Mind me asking what G5 you own? Is it a Quad like I have and BDAqua? Also, where can I get this pump if I ever ever need to replace a dying pump in my Quad? I really don't wanna think about this, as I have the revision 2 pump and I have never had leak problems with my LCS system; I don't even wanna think about it!

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Answer 4

madroadbiker Author

Level 1

8 points

Apr 9, 2011 9:27 AM in response to romko23

It's a dual processor G5 manufactured in 2004. You can get the pump from
http://www.newegg.com/Product/Product.aspx?Item=N82E16835108063&Tpk=mcp350

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Answer 5

Nov 1, 2011 6:23 AM in response to madroadbiker

Hi madroadbiker,

when replacing your G5 (Delphi?) pump with the new MCP350, do you remember how you wired it to go from three wires to four?

I have just got a Laing pump, which should be identical to the Swiftech. It has three wires (black/blue/yellow = ground/tacho/12V) and a blank connection on the PCB. I'm wondering if that blank could go straight to the fourth wire and provide variable speed control?

Other threads speak of a bridge between two pins on the PCB, one of which is the 12V and the other the variable speed, but my PCB (DDC3.1) just has a blank connection at position 3 as you look at it. Any info would be much appreciated.

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