• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Water Cooling pump reliability/Hx efficiency

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.


Nov 16, 2001
The fan noise has finally become too annoying so I want to convert to water cooling. My Swiftech cooler does an outstanding job now cooling my overclocked Northwood so my primary goal is to eliminate or greatly reduce the fan noise. I have two questions now that I would appreciate some advice about.

First, what is the reliability of the pumps? My computers runs 24/7 crunching SETI work units so the pump will obviously have to last. I did see a posting in another forum that said even the higher quality Ehiem pumps do not last under a 100% duty cycle. It implied that the life of the pumps could only be measured in months. I am also concerned about the pump being a fire hazard if it fails since they are 120 volt devices. Unless i can find a pump that will run continuosly I will have to abandon this project.

Second, the Maxxxpert kit has much appeal to me. The heat exchanger that comes with the kit will fit very nicely inside my Lian-Li case and it appears that all the parts are of a high quality. It also is a nice convenience buying everything in a self contained kit. I would be interested in learning more about the efficiency of the heat exchanger Maxxpert supplies. In other words, how good is its heat transfer characteristic?

In addition to my P4, I have a second machine running an overclocked Tualatin. It is also noisy and it runs too hot. If water cooling is successful on my first machine, I intend to water cool the second machine also. I have no experience with water cooling so any advice would be greatly appreciated.
The fan noise has finally become too annoying so I want to convert to water cooling

It's unfortunate that most of us learn this the hard way. I am not upset though. Using air cooling first gives you an idea of what's good or not in a water cool setup.

First, what is the reliability of the pumps?
Probably the best place to ask that question is an Aquarium shop.
I got my pump at one and they told me my Danner 500 would last a long time. I know that's vague but it doesn't sound like a matter of months to me. If you are conserned abuot continual usage though you could run two pumps in-line and alternate them. You could even setup a timer between them both. You might even be able to setup a switch that would automatically start the other pump if one were to fail. Good luck and have fun.
If you get a decent pump reliability is not a problem. I have had my $20 Maxi-Jet 1200 running 24/7 for well over 6 months now and it has been great. I have heard of these pumps lasting 8 years without problems. Remember this style pump is mag drive, meaning it has only 1 moving part. With only the impeler magnet assembly moving you dont have seals to go bad. Pumps I reccomend are the Maxi Jet 1200, Danner 250-350+ GPH, an Eheim 1048 or 1250. All the pumps should last pretty much forever. Fire is not really an issue for pumps. Almost all accept a few of the cheepo rios are UL listed.
RhoXS said:

First, what is the reliability of the pumps? My computers runs 24/7 crunching SETI work units so the pump will obviously have to last. I did see a posting in another forum that said even the higher quality Ehiem pumps do not last under a 100% duty cycle. It implied that the life of the pumps could only be measured in months.

Think about that statement. Given their popularity, lets assume there are 500 Eheim pumps being used by overclockers around the world. One person posts a bad experience. Does that automatically disqualify the other 499 units from consideration? That does not count the untold thousands of them in use in aquariums, fountains, waterfalls and other hobby ponds. I think I would look for a larger opinion base than one.

I've only had mine in service for three months, so I'm not totally sure how long it will last. I do open my cover a minimum of once a month for preventive maintenance and I do check everything for signs of leakage. That's just good sense. Time will tell.

One of the pumps that I have has several years on it. It started life its life running my salt water aquarium that I no longer have and has found its way into my h2o cooling system well over a year ago. As long as you stay away from the cheap pumps you shouldn't have any problems. If one of these things can hold up to the harsh environment of saltwater tanks a cooling system shouldn't cause to much of a concern. Eheim and Danner are highy reccomended pumps bescause of their reliability.
The point I'm trying to get at is that, like Hoot said, there thousands of these things out there and there are going to be failures all these people with with expensive rigs aren't going to talk these things up like they have for the past year or so if they are junk and people that buy them for $10k salt tanks sure wouldn't continue to buy them if they lost all their fish every few months when they were away. Your fan could die and cause you problems too!
Sorry for rambling for so long but it aggrevates me when I see guys being given bad info by a few that had problems! Go watercooling!!!!!!!!!
Plus, if you're REALLY worried about fire, submerge the pump. Most of them are meant to be submerged, plus doing so helps to cool the pump, which may help the life as well. I'm still debating on mine. I'm going to build my own reservoir from plexiglass, but I'm unsure how to connect the hoses. It's going to be located in a separate chamber underneath the case so I've got to figure out how to get it in there and remove it if need be. I'm open to suggestions.
I wonder why everyone seems to use a closed loop for water cooling.

I calculated the cost of cooling without a pump, radiator, etc and just running tap water through the block and down the drain. It's pretty low.

Of course, it's not great for the environment and it would probably corrode your block eventually.

The best way to connect your hoses would probably be to use brass hose barbs. You can get them at Home Depot or other hardeare store. Also not all aquarium type pumps are meant to be submursed so before you submerse your pump make sure it is made to be if not you are inviting severe problems!:beer:
Well, I'm looking at most likely either an Eheim or a Danner. Possibly a Rio, but for the same money, I'd rather get the Danner. All of those, if I'm not mistaken are made to be either submerged or inline. At least the ones I'm looking at (200-300 gph range) ones are.
RhoXS, given your concerns, have you considered
reducing the fan voltage? You might be surprised
how much it can reduce the noise to do so.

Cheaper that converting to WC. :)
you could buy several rios and run them in parallel, so if one gives out, youre still in buisness. youd need some sort of sensor to tell you that one of the pumps died though. The best thing is rio pumps are CHEAP
When I posted the original question above I was just starting to learn about watercooling. I have since (today) ordered what I expect to be a complete complement of parts to convert my very efficient and somewhat warm background noise generator into a quiet, well cooled, self contained, computer.

I ordered an Eheim 1048 and, thanks to many of the responses above, I am no longer concerned about pump reliability. My level of concern is now focused on much more specific details.

For example, the 1048 is specified, by Eheim to have a 4' 11" discharge head. I have to assume, in the absence of any other data, that this is the maximum or cutoff head. This head will of course decrease as the flow increases and be smallest at the suction of the pump. I want to install a small surge tank in the form of a standpipe to accomadate thermal expansion, etc. This standpipe would connect to the highest point in the system (water block discharge) to accomadate air removal. Also, the top of this standpipe has to be able to breath to atmosphere. If the head is more than a few feet (the hieght of my case) water will squirt out the top. Since I do not know what kind of head to expect at the actual flow rate, I do not yet know how to implement this necessary feature.

Anyway, that is now my major concern. I am expecting the parts on Monday (from Danger Den) so I guess I will have real world practical experience soon. Again, Thanks for all the helpful replies.
Your tubing will provide all the thermal expansion
capability you need. There is no reason to have your
system open to the air. Air removal from the system
is covered elsewhere, but is no problem even for
the in-line setups.