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ricecrispi · 09-28-2005, 01:34 AM

Liang DDC
After the start problems on certain Laing DDC pumps preventing their usage. I wasn't sure of their usage for watercooling. I started a discussion with a technical person in charge with Laing Germany, Ralf Dörrenberg. They assured me they would try to locate and attempt to resolve the problem.

For the Liang pump, the start-up phase is very delicate. For it to start it is necessary to be able to magnetically start the rotor to induce to spin until it attain the appropriate cruise speed. Now, at this precise instant, the couple that serves to turn the body is weak and must fight against inertia and the frictions that opposes the rotor to the stop. The Laing DDC therefore programed to do several start attempts if she does not detect rotation, but it wnough to turn on in my case.

The DDC is a very optimized pump at a high level and not enough power for it to engage due to lack of power (manufacture tolerances). It is necessary then to tap it lightly to help it to launch itself. That is unacceptable for WCing!

Despite their tests on "defective" models, Laing Germany could not reproduce this this error that occurs in a small number of pumps. Laing USA was able to reproduce this phenomenon with a pump originating from a kit Corsair discovered by SystemCooling, with 3 failures for 20 start attempts.

It is necessary to know that Laing furnishes Apple in very big volume for their machines (more than 150000 unities). When comparing the thousands destined for apples, they never inventoried this defect. When I was able to obtain my DDC in August 2004 before available to retail....French mobojombo.. i had problems with a special sample pump.....

More verbose french language explaining that the pump doesn't work........

My very short summary of the cause fo the problem.

Apple had the pump design for tight tolerances and had less than 1% error in their units. So the problem with pc users is if you have less than the required 12 Volts you are screwed and the pump wont start. It is better to have 12.3 volts than 11.6 volts to start the pump.

Apple uses a different glycol/additive water mixture [80:20] that protects against formation of deposits. Not using this special additive may have formed deposits(carbon?) or liquid fomations that might have caused increased drag on the rotor.

A revision was released and current models do not have this problem. Some software adjustments and electrical modifications allows the pump to draw the required power to start. I have retested the pump in several diffrent conditions , restarts, and different coolants to see if the problem still exist and it's the pump revision works

Comparisons with the new revision

To verify the revisions, Laing Germany furnished me a new revision to compare to the old ones. I compared the new version, V2, to the old V1 to see if they perform the same and if the new revision worked properly. I open the sheel to see if any changes were made.

Except the fact that the wire of tachméter is put some places directly, the only change is fixing paws were added (already in places in certain revisions). The PCB was reworked lightly and one notes some differences at the level of the electric circuits.

Some french blab about delaying the startup of the pump to store enough charge in the capicator to help give the pump enouh current to start. Some test was doen to verify something I can't translate.

More mobo jumbo and the revision works and thats all I can stand for...

09-28-2005, 01:34 AM	#16
ricecrispi Cooling Savant Join Date: Jul 2005 Location: california Posts: 429	Liang DDC Liang DDC After the start problems on certain Laing DDC pumps preventing their usage. I wasn't sure of their usage for watercooling. I started a discussion with a technical person in charge with Laing Germany, Ralf Dörrenberg. They assured me they would try to locate and attempt to resolve the problem. For the Liang pump, the start-up phase is very delicate. For it to start it is necessary to be able to magnetically start the rotor to induce to spin until it attain the appropriate cruise speed. Now, at this precise instant, the couple that serves to turn the body is weak and must fight against inertia and the frictions that opposes the rotor to the stop. The Laing DDC therefore programed to do several start attempts if she does not detect rotation, but it wnough to turn on in my case. The DDC is a very optimized pump at a high level and not enough power for it to engage due to lack of power (manufacture tolerances). It is necessary then to tap it lightly to help it to launch itself. That is unacceptable for WCing! Despite their tests on "defective" models, Laing Germany could not reproduce this this error that occurs in a small number of pumps. Laing USA was able to reproduce this phenomenon with a pump originating from a kit Corsair discovered by SystemCooling, with 3 failures for 20 start attempts. It is necessary to know that Laing furnishes Apple in very big volume for their machines (more than 150000 unities). When comparing the thousands destined for apples, they never inventoried this defect. When I was able to obtain my DDC in August 2004 before available to retail....French mobojombo.. i had problems with a special sample pump..... More verbose french language explaining that the pump doesn't work........ My very short summary of the cause fo the problem. Apple had the pump design for tight tolerances and had less than 1% error in their units. So the problem with pc users is if you have less than the required 12 Volts you are screwed and the pump wont start. It is better to have 12.3 volts than 11.6 volts to start the pump. Apple uses a different glycol/additive water mixture [80:20] that protects against formation of deposits. Not using this special additive may have formed deposits(carbon?) or liquid fomations that might have caused increased drag on the rotor. A revision was released and current models do not have this problem. Some software adjustments and electrical modifications allows the pump to draw the required power to start. I have retested the pump in several diffrent conditions , restarts, and different coolants to see if the problem still exist and it's the pump revision works Comparisons with the new revision To verify the revisions, Laing Germany furnished me a new revision to compare to the old ones. I compared the new version, V2, to the old V1 to see if they perform the same and if the new revision worked properly. I open the sheel to see if any changes were made. Except the fact that the wire of tachméter is put some places directly, the only change is fixing paws were added (already in places in certain revisions). The PCB was reworked lightly and one notes some differences at the level of the electric circuits. Some french blab about delaying the startup of the pump to store enough charge in the capicator to help give the pump enouh current to start. Some test was doen to verify something I can't translate. More mobo jumbo and the revision works and thats all I can stand for... Last edited by ricecrispi; 09-28-2005 at 02:02 AM.