Need to adjust voltage on my old MCP355 pumps

A

arnemetis

2[H]4U
Joined
Aug 2, 2004
Messages
4,086
Hello everyone,

After the fun I had in my last thread, I decided to reuse a lot of my existing water cooling gear. The problem I am having is the first pump has a grinding/humming type noise that is only present when both pumps are running. If I unplug one or the other, the one left running is effectively silent. They both run between 4400 - 4600 rpms. This never happened before my upgrade, they've been running for 9 years like this. Taking the loop apart is out of the question because of the way my system is set up, it would take two full days to drain, disassemble, and fill the loop up again. But given that it's quiet with just one pump running, there's something about them running together that the first pump doesn't like (and rules out theories like the pump top being on too tight and the impeller hitting the top.) I am thinking running them a bit slower will quiet it down.

So what I'm looking for is a controller or set of adapters that I can adjust the voltage to these two pumps with. They are rated for 12v at 1.5 amps each. In an ideal world I would have one knob I could adjust them with, but that would have to be pretty beefy at 36 watts. I will probably end up with two that handle 20 watts each, and have to very carefully adjust them to be as close to each other as possible.

One problem I'm finding is since the pumps get power from a molex connection and not the 3 pin, a lot of fan controllers won't work for me. I could live with something like this http://www.frozencpu.com/products/9...Speed_Controller_-_4-Pin_Molex_Connector.html if it could handle more amps/watts. I CAN live with this, but I don't plan on upgrading again for 3+ years so if I can reduce the noise that's bothering me now that would be great.
 
86 5.0L said:
I bet there's some cavitation/trapped air bubble going on, you could try shaking the pumps when theyre running. is this a newly filled loop?

or try this trick to get 7v to the pump

http://pcsilencioso.com/cpemma/7volt.html
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I shook the ever loving hell out of this loop initially, it's been running since xmas weekend. Again if there was an air bubble, wouldn't that keep the pump noisy when I unplug the other one? It's a very odd situation and I don't know why the first pump gets noisy with the second one running. In case I wasn't clear, the pumps are in series for redundancy one right after the other, about 3" of tubing between them.

Additionally I do have a 12v to 7v switch I use for my 8 fans, plugging the pumps in was no good because the pumps don't operate under 8v. I might have used that exact webpage 9 years ago to make my switch!
 
86 5.0L said:
Cavitation happens even with no air, the 2nd pump pulls the water out of the 1st pump faster then what the first pump can push out.

Maybe something like this to slow down the 2nd pump just a little

https://www.amazon.com/gp/aw/d/B00F...v+rheostat&dpPl=1&dpID=51sZEFy9ShL&ref=plSrch
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Hmm I might grab a few of those to try it out. I'm a little unfamiliar with this kind of unit, do I just run 12v and ground to the power side, and attach the pump's 12v & ground to the motor side?
 
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arnemetis said:
I'm worried about cooking it due the load on it. I'm no pro at electronics so I figured I couldn't just grab any old pot I had from old fan controllers.
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As long as the or is rated for the load, you should be fine.

I'd personally suggest an Aquaero. You can wire your pumps with fan connectors and control them from the Aquaero software. The headers on the unit are rated for 2.5a apiece.
 
VanGoghComplex said:
As long as the or is rated for the load, you should be fine.

I'd personally suggest an Aquaero. You can wire your pumps with fan connectors and control them from the Aquaero software. The headers on the unit are rated for 2.5a apiece.
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Wow sorry no, those are very expensive for something I will likely adjust once and never touch again. Plus I would need to find molex to 3 pin adapters.
 
arnemetis said:
Wow sorry no, those are very expensive for something I will likely adjust once and never touch again. Plus I would need to find molex to 3 pin adapters.
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Yeah, I guess if that's all you're after it's a little overkill. I'm just in love with mine. Last fan & pump controller you'll ever need to buy.
 
arnemetis said:
Hmm I might grab a few of those to try it out. I'm a little unfamiliar with this kind of unit, do I just run 12v and ground to the power side, and attach the pump's 12v & ground to the motor side?
Click to expand...

Idk, I just googled 12v rheostat :X

EDIT: yeah looks like positive/negative hook up to it for both pump and psu. I would probably add molex leads/connectors
 
arnemetis said:
One problem I'm finding is since the pumps get power from a molex connection and not the 3 pin, a lot of fan controllers won't work for me.
Click to expand...

Many fans come with Molex/3-pin adapters. I've been using one to connect my pump to some Lamptron touchscreen controller I bought from Amazon. It's worked fine for a couple years now.
 
DeathFromBelow said:
Many fans come with Molex/3-pin adapters. I've been using one to connect my pump to some Lamptron touchscreen controller I bought from Amazon. It's worked fine for a couple years now.
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Yeah all my fans have the 3 pin integrated into the cable. I know I could hack something up. I'm still mulling over the controller 86 5.0L posted.
 
arnemetis said:
The problem I am having is the first pump has a grinding/humming type noise that is only present when both pumps are running. If I unplug one or the other, the one left running is effectively silent. They both run between 4400 - 4600 rpms. This never happened before my upgrade, they've been running for 9 years like this. Taking the loop apart is out of the question because of the way my system is set up, it would take two full days to drain, disassemble, and fill the loop up again. But given that it's quiet with just one pump running, there's something about them running together that the first pump doesn't like (and rules out theories like the pump top being on too tight and the impeller hitting the top.) I am thinking running them a bit slower will quiet it down.
Click to expand...

How are your pumps plumbed? One after the other? Sometimes there's an anomaly that is known to happen with pumps in series. The easy way of fixing it is to separate the pumps to different parts of the loop.
 
thesmokingman said:
How are your pumps plumbed? One after the other? Sometimes there's an anomaly that is known to happen with pumps in series. The easy way of fixing it is to separate the pumps to different parts of the loop.
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They were fine this way for nine years, and changing the plumbing is completely out of the question. Thanks for the suggestion though. Probably going to order two of those controllers tonight.
 
Dude, just throw the pumps on a fan controller that's rated at 30w or more per channel, done.
 
thesmokingman said:
Dude, just throw the pumps on a fan controller that's rated at 30w or more per channel, done.
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Please give me a suggestion for one that's $30 or less? I'm going to set this down one time forever, the benefit of having most expensive controllers is regular changes and monitoring, which I don't need or want.
 
arnemetis said:
Please give me a suggestion for one that's $30 or less? I'm going to set this down one time forever, the benefit of having most expensive controllers is regular changes and monitoring, which I don't need or want.
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Here you go. I think you really only need to control one of your pumps to get rid of the noise you're experiencing, and I'd bet my money that what you need to do is slow down your second pump just a smidge.

http://www.performance-pcs.com/lamptron-cp120-pci-slot-mountable-3-pin-fan-controller.html

I'm kinda surprised you think two pumps makes sense, but view sophisticated controls as excess... *shrug*

This is a 20w controller on the cheap. It's the first thing I could find that met your criteria, but there are boatloads of them on Performance-PCs. =)
 
VanGoghComplex said:
Here you go. I think you really only need to control one of your pumps to get rid of the noise you're experiencing, and I'd bet my money that what you need to do is slow down your second pump just a smidge.

http://www.performance-pcs.com/lamptron-cp120-pci-slot-mountable-3-pin-fan-controller.html

I'm kinda surprised you think two pumps makes sense, but view sophisticated controls as excess... *shrug*

This is a 20w controller on the cheap. It's the first thing I could find that met your criteria, but there are boatloads of them on Performance-PCs. =)
Click to expand...

Thanks, that's a good suggestion. Of course now the issue of 20 watts not actually being enough has come up...

thesmokingman said:
20w controller will fry over time. The Laing pumps draw around 30watts. You can use a Sunbeam Rheosmart 6 or others like the NZXT Mesh, both 30w per channel.

http://www.xoxide.com/sunbeam-rheosmart-6-fan-controller.html
https://www.bhphotovideo.com/bnh/controller/home?A=details&O=&Q=&ap=y&c3api=1876,{creative},{keyword}&gclid=Cj0KCQiAkZHTBRCBARIsAMbXLhGSPcRd7vJt_c8XsxqGHGIY1adghikEhyVwR8hU8LjkAGzHj9xnOjQaAtZOEALw_wcB&is=REG&sku=1165537
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That NZXT one is a nice price, even though I have to consider it being a special order for b&h with $9 shipping and it taking another two weeks to ship. I've tried looking this up some more, but all I'm finding are other people on the net also commenting that these pumps use 30 watts. However the MCP355 I have says it's rated for 12 volts, 1.5 amps. That should only be 18 watts on a controller. So has Laing been lying about their power draw for 10+ years, or are most fan controllers garbage that are not actually capable of the rating they advertise?

Edit: I ordered the nzxt one, even paying shipping waiting 2 weeks for it to ship. Now I need to dig through my parts and do some butt splices to combine the pump power wires back into the 3 pin with the rpm wire.
 
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86 5.0L said:
why not that little $10 controller?
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Really want to be able to control both, just my luck I slow one down and the other one ends up noisy. Plus the concerns that the pump will burn up 20w controllers, so I just decided to pony up for more.
 
arnemetis said:
Really want to be able to control both, just my luck I slow one down and the other one ends up noisy. Plus the concerns that the pump will burn up 20w controllers, so I just decided to pony up for more.
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I don't think your 18w pump will burn up a 20w controller, as long as you're only using it to slow the pump a little bit.

Those simple controllers just dissipate the wattage you're shunting away from the pump. So if you're just reducing your pump from 12v operation to 10v, you're only dissipating a handful of watts at the controller, nowhere near its 20w rating.
 
VanGoghComplex said:
I don't think your 18w pump will burn up a 20w controller, as long as you're only using it to slow the pump a little bit.

Those simple controllers just dissipate the wattage you're shunting away from the pump. So if you're just reducing your pump from 12v operation to 10v, you're only dissipating a handful of watts at the controller, nowhere near its 20w rating.
Click to expand...
Yeah that's what I thought too. Might use the other channels to control my fans too, who knows. I was pretty angry that b&h took three days to tell me the item I special ordered had been discontinued, so I wanted to order something that would work. Might have been a bit hasty to buy.
 
Yeah I was in a similar situation long ago. I settled on the Lamptrons, I think they can handle it, also the aquacomputer controller too, I forgot what it's called
 
86 5.0L said:
Yeah I was in a similar situation long ago. I settled on the Lamptrons, I think they can handle it, also the aquacomputer controller too, I forgot what it's called
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I think Aquacomputer's is called the Aquaero. It's been suggested and refused in this thread. XD
 
arnemetis said:
Yup, it's in the $150+ price range so another league of controllers. Wasn't interested in spending that kind of money on the controller.
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I know this probably doesn't make a difference, but the LT versions (without a display) are closer to $100. That's the kind I was advocating, but if it's more than you need it's more than you need.

I just love them for watercooled systems because you can do really cool things with them, like control fan speed based on coolant temp (instead of component temp) and lots of other functions.
 
Yeah they're pricey and pretty complex. I think the Lamptrons were the only ones I could find that could handle higher amps while being cheap enough
 
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So the Laptron CM430 is working well. Even in it's default state where 100% is really 11.2v, it made a difference. I've settled on the first pump at 70% and the second pump at 60% (9.5v / 3,480rpm & 8.6v / 3,180 rpm) and my system is ridiculously quiet with the 120mm fans in the 7v position. Still moving enough heat too, 5.1ghz 8700k @35-55c with everyday workloads while the 1080 ti is at full tilt mining all day @ 40c. Ended up being $33.10 with shipping.
 
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