How to reduce your water-cooling pump voltage

Mostwater-cooling systems don't need their pumps continuously on
full power. Antony Leather shows you how to slow them down

As with case fans, you can reduce the noise and vibrations
from your water-cooling pump by dropping its voltage.
Although variable speed pumps, such as Laing's D5 Vario.
are available, they're also expensive, but there's a much-cheaper way
to reduce your pump's voltage. By rewiring it to specific cables on a
Molex connector, you can reduce the voltage from 12V to 7V.
This can reduce noise and vibration to the point where the pump is
inaudible. but with enough power to still keep coolant flowing round a
loop and, in most cases, with a negligible effect on temperatures. We'll
also look at using a 3-pin-to-Molex adaptor to convert a 4-pin Molex
pump so it can be used with a fan controller. We're using an adaptor to
keep our pump in new condition, but you can apply the same method
directly to your pump cables for a neater job.

Tools you'll need

Molex extractor/ cable modding kit	Soldering iron and    solder
Insulating tape	Cheap fan with 3-pin connector and molex to 3-pin adaptor
Wire stripper or pliers

1 / IDENTIFY CABLES You need to insert your current pump cables mo the outer cable (7V) slots on a 4-pin Molex plug The flat side of the plug usually shows that the sockets are numbered 1-4 - most Molex- powered pumps have two cables a black or ground wire in socket 2 and a 12V wire at the edge in socket 1	2 / REMOVE MOLEX PIN Use a Molex pin extractor to remove the ground (2) cable from your pump. On our Laing DDC pump, the cable is black. rather than red. Push the extractor all the way in and pull on the cable from the other end - it might need a couple of attempts but It will eventually pop out.
3 / INSERT PIN INTO OUTER SOCKET lnsert the black cable into the outer socket (4). The metal flanges on the pin may need to be bent outwards again to allow the pin to lock into place. Your pump will now run at 7V. You can also run it at 5V, but we don't recommend it as some pumps won't start at such a low voltage.	4 / OBTAIN FEMALE 3-PIN CONNECTOR You can also convert a3-pin adaptor, which are included With many fans. so vou can connect your pump to a fan controller. Cut a 3-pin female connector off a spare fan. as the control cables on fan controllers are male. You'll only need the red and black cables.
5 / CUT OFF 3-PIN CONNECTOR Now you need to cut off the male 3 - pin connector from your adaptor cable,noting the order of the cables so that you can attach the new connector cables in the right order. Cut it near  the connector so you have plenty of cable to work with	6 / STRIP THE CABLES Use a wire stripper pliers to strip 5mm or so off each length of cable so you can solder them. Once you're done, twist the ends slightly so they don't fray. which will make soldering difficult.
7 / SOLDER 3-PIN CONNECTOR It can help to use a clamp or Helping Hand  magnifier to hold the two cables together while you solder them. Apply a small amount of solder and allow it to run into the joint securing the cables together	8/ INSULATE WITH TAPE You'll need lo insulate the joints completely - insulating tape can work well. or you can use liquid electrical tape, which looks neater but takes a while to dry.
9 / TEST PUMP whether you modded the Molex cable or converted it to a3-pin pump and hooked it up to a fan controller, you need to make sure it works before you pop the side panel back on your PC. You can also use a multimeter to check that the voltage is correct