I had a bizarre, or at least confusing experience today and wanted to get some feedback plus rant a little. I thought I would finally retire the little baby pump I am using and upgrade. I found what seemed to be a real good mag drive pump at Lowe's. Rated 300 GPH with a 12 foot shutoff. 55 bucks so I thought I would give it a try. It was one of those combo units that can be a submersible or in-line. My volume and pressure shot way up and I thought I had a winner.

Now the odd part. My temps actually went up. After a while even my inlet temp went to 28C, which it had not done in two days. So, I'm scratching my head more than a little bit, then realize it is due to this damn pump dumping a massive amount of heat into the GLoop. It was hot to the touch, too hot to hold comfortably for more than a several seconds.

Put the little guy back in and the inlet temp returned to 27C and the machine temp was lower. Heck of a thing.

Now I have read of this type of thing in passing, but it seems that nobody puts a fine point on it. It seems to me that this big hooraw about high flow may be more of the typical "conventional wisdom" turned manure than truth. The first thing we should know about a pump is how much heat it is dumping into the loop. That, and how it then effects inlet temp, are much more important to my way of thinking, than flow.

I am finally coming to understand why my little 126 GPH, 2-4 foot head pump can cool so well as I'll bet it does not put much heat in, plus a large flow is not needed. If flow is so darned important how in the hell is this little guy pushing through near 50 feet of tubing and still cooling a 200 watt load with barely what I would guess is 1/2-3/4 GPM? - (I ought to measure that someday)

That was a bit of a rant, I guess :=) I'm feeling frustrated. I thought a better pump would help, not hurt, and I am starting to think a lot of the information put forth on the pump subject may be bogus.

Does anybody know where I could find some figures on how much heat various popular pumps dump into the cooling loop? That is where I'm going to start. The hell with flow :mad: (with a wry grin)

Very cool project DDogg. Pretty impressive that it worked out so well too for rather an unusual idea. If you ever build a new house maybe you'll plumb all the rooms for cpu water cooling along with the phone, cable, and ethernet lines ;-)
I'm reinspired to get my new water cooled case finished, think I'll stick to undervolted AC fans to avoid all that digging though.

Cathar is your man. Quite a few threads about pump heat around, maybe try a search?
How many watts is the Lowes pump?

I think it was 70 watts which would make sense given the heat.

I ended up getting another $19.00 126gph/4 ft head fountain pump and built it into a 4x4x2 watertight electrical box (making it into an in-line). Pretty cool really. It has 4 tabs for mounting on the wall and it is mounted on the wall where my return comes in from the GLoop. Neat, tidy and near silent. Total cost was slightly under 30 bucks.

It only uses 10 watts and I put it in series with my other one. Pressure and volume increased a fair amount and it looks like it may have bought me 2-4 C on CPU temp. Too soon to tell on the temps, but either way it is nice to have the twin redundancy.

/Add: I forgot to mention my inlet temp went to 28C today after three days of pumping 180-200 SiSoft watts into the GLoop. Hopefully that will be my stable temp. I have my fingers crossed.

Re: MCW5002-AT - Just 8-10 sub ambient without condensation worries?
 

Any updates on this thing? :) hehe..