Evolution of a Watercooling System

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Interesting tips based on experience – Nick Poirier


This design is my 5th or 6th revision and represents the highest performing system I have come up with yet. Some of the previous designs had all of the water-cooling components inside my case – I found designs like that were very awkward and limiting. Although they worked, I knew it could be done better. And after 2-3 years of water-cooling, this is the result I came up with.

Basic picture of the overall case:

  • The case’s feet were removed and the case was screwed down to the wooden box below
  • A thin piece of wood is between the case and box to act as a “shim” because the bottom of the case has many rivets sticking out the bottom
  • A 4″ x 3″ hole was made in the bottom of the case, wooden “shim”, and the top of the box to allow the hoses to pass through

    An overall picture of the wooden box (with the side piece removed):

  • The wooden box’s overall size is 21″ tall, 10.5″ wide, and 23.5″ deep
  • Inside the bucket (reservoir) is a Laguna PowerJet 2000 pump (1.25″ inlet, 1″ outlet, ~55 watts heat output, 3700 l/hr rated flow)

  • The bucket holds 10-12 litres of coolant (distilled water + water wetter) and is sitting on some soft foam to isolate the pump and minimize vibration related noise
  • The edge of the bucket had to be trimmed to prevent it touching the sides of the box (to prevent pump vibration noise)
  • I have three 120mm Sunon fans (each does 90 cfm @ 12v) hooked into my custom fan controller
  • A small 50mm fan mounted at the top of the box cools the heatsink attached to the voltage regulator on the fan controller
  • Behind all the wires/hoses/pipe is a 3 amp 12.6v transformer (green/gold colored box) used to power the fans
  • Behind the 120mm fans are two heater cores (each 8″ x 7″ x 2″ with 0.5″ hose connections)
  • The top heater core accepts the CPU block coolant while the bottom core receives the GPU/chipset coolant
  • The fans are secured to a removable shroud which holds them 1″ off of the surface of the heater cores
  • The shroud is sealed with sticky-back foam to prevent air leakage

    Closer look inside the PC:

    Plumbing 1
  • Swiftech MCW-5000A water block on the CPU (AMD TBredB 1700+)
  • Swiftech MCW-50 on the GPU (GeForce4 Ti 4400)
  • DangerDen “Z-Chip” block on the Northbridge (nForce2 Ultra 400 – Abit NF7-S Rev 2 motherboard)
  • Both the northbridge and GPU have been lapped to improve heat transfer

    Plumbing 2
  • The 1″ outlet hose from the pump goes straight up out of the reservoir (bucket) from below and into a two-way splitter (each split is 0.5″)
  • The CPU block gets one feed…the GPU and Northbridge get the other (GPU first – then chipset – in series)
  • Both 0.5″ outlet hoses/pipes go down back into the box below and into the heater cores
  • That is regular 0.5″ house-hold copper piping (because its cheap and you can get it anywhere)

    Nick Poirier

    This is the back of the wooden box:

  • Power for a 5 amp, 12v relay comes in at the top-left
  • The relay powers the pump and fan controller when the PC is turned on
  • The wood which makes up the box is 0.5″ G1S fir plywood

    This shows the previously removed side panel for the box:

  • At the top is a plexi-glass window
  • At the bottom is a piece of filter material (it’s about 0.75″ thick)
  • When the side panel is screwed on tight the air moving through the box is filtered very well (the 120mm fans suck air into the box through the filter)
  • Also because the filter is on the side (as opposed to the front) the fan noise is noticeably reduced when sitting in front of the PC

    Two overall pictures of the complete package:

    Overall 1
  • I have two CompuNurse digital temperature sensors mounted in a 5.25″ drive bay cover
  • The air temperature sensor is located between the top 120mm fan and the heater core

    Overall 2
  • The coolant temperature sensor is submerged in the coolant inside the reservoir (bucket)
  • (Note: these two pictures are older and do not show the sensors at their current location)

    This picture vividly displays the awesome difference between my old Eheim 1046 and the Laguna PowerJet 2000:

  • The 1046 has a 3/8″ outlet, 1/2″ inlet, puts out 5w of heat, and moves 300 l/hr
  • The PJ2000 has a 1″ outlet, 1.25″ inlet, puts out 55w of heat, and moves 3700 l/hr
  • More details on the Laguna pump can be found HERE

    A close-up picture of the fan controller:

  • I found the design schematics online. I was told it’s a pretty standard circuit (LM-317 voltage regulator circuit)
  • The 4-pin Molex connector on the left is connected to the 12.6v transformer
  • The variable resistor (Pot) at the top allows me to adjust the fan speeds
  • I have since replaced that wimpy heatsink on the voltage regulator with a much bigger one


  • I get a coolant temperature 1-3’C above the ambient air temperature (depending upon how fast the 120mm fans are running)
  • The fastest I have ran my 1700+ was ~2800 MHz (2700 MHz is 99% stable, 2600 MHz 110% stable)
  • The fastest I am able to run my chipset is 220 MHz (440 DDR) however I believe this is because I am only running the chipset at 1.7v (the max available before modding the motherboard)
  • I am able to overclock my GPU to 325 MHz (275 MHz is the default) and the VRAM to 655 MHz (550 MHz default)

    Identified Issues/Problems

  • My fan controller needs to be touched up as it sometimes cuts power to the fans (loose solder connections I assume)
  • I need to get another piece of 0.5″ hose to replace the copper pipe which goes right up to the CPU block
  • I believe my CPU block is not seating properly (ie it is not pressing on the CPU strong enough) due to the copper pipe holding it to tightly
  • I think the Danger Den chipset block is leaking air into the hoses because there is always a stream of micro air bubbles in the block’s outlet hose

    Possible improvements: (suggested by myself and others)

  • Put a small light bulb or cold cathode inside the box and wire it up to a convenient switch (to allow better viewing of the internal workings)
  • A window for the PC side panel (until recently I had not cared much for windows)
  • Paint
  • UV dye in the coolant
  • LED fans
  • Less 90 degree bends in the copper piping to improve flow rates

    Nick Poirier

  • Discussion

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