Components and Design



The high-flow reservoir is manufactured by CoolingWorks and was designed to fit into a spare 5.25′ drive bay and is molded from high-density polyethylene for long term durability.  The reservoir was specially designed to operate efficiently with a high-pressure pump, just like the one supplied with the COOL kit.


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Reservoir — Key Features


  • Designed to easily mount in spare 5.25′ drive bay
  • Stepped down discharge compartment to eliminate recirculating air bubbles
  • Versatile inlet and discharge ports (3/8′ NPT)
  • Dual inlet ports for systems using parallel flow thru multiple waterblocks
  • Durable blow-molded plastic construction for long life
  • Fill hole cap with O-ring seal

This is one of the best bay reservoirs on the market and offers good flexibility with many different system configurations.  The large threaded ports permit using a variety of fitting sizes, ranging from 1/4′, 3/8′, 1/2′, or even 5/8′ barbs or quick-connect adapters.  Since the COOL water cooling kit uses 3/8′ ID tubing throughout, the reservoir comes with 3/8′ barb fittings pre-installed.


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The reservoir contains two adjoining compartments, with the taller compartment being designed to trap air bubbles and keep them from recirculating thru the system.  Ideally, the reservoir will be mounted into the case with drive rails, which will allow sliding it out for easy access to the fill port.  This makes it very easy to periodically top off the system.  (Note: Even in a closed system with no leaks, water vapor will slowly pass thru the plastic tubing and decrease the water level slightly in the reservoir.)





The pump used in the COOL kit is Delphi DC pump (DDC) co-developed and marketed in North America by Laing and also sold by Swiftech.  The DDC is based on the OEM Apple G5 2.5 GHz liquid cooling system pump.  It was specifically designed to provide high reliability, above average head and compatibility with systems incorporating 3/8′ ID tubing.  The DDC operates on 12 VDC and is an inline pump, which means it is not designed to be submerged in a reservoir and must not be run dry.


You can read my review of the Laing DDC pump here: DDC 12V Pump review


DDC – Key Features


  • Small footprint: 2.4 x 2.4 x 1.5′
  • 50,000 hours MTBF* (equivalent to 5 year lifetime)
  • Convenient 12 VDC operation (plugs into PC power supply)
  • Superior real world performance (high pressure characteristics)
  • Quiet operation (24 to 26 dBA)
  • Maintenance free operation (when used with DI water and biocide)


 DDC – Technical Specifications


  • Nominal voltage:                         12 VDC
  • Operating voltage range:            6 to 13.2 VDC
  • Nominal power (@ 12V):            8.3 W
  • Nominal current (@ 12V):            .69 A
  • Nominal speed:                          3,600 RPM
  • Nominal head (@ 12V):                13.05′ (5.7 PSI)
  • Nominal flow (@ 12V):                ~92 GPH (350 LPH)
  • Connection size:                 3/8′ OD barb (10mm)
  • Maximum working pressure:            22 PSI (1.5 Bar)
  • Operating temperature range:            Up to 140°F (60°C)
  • Electrical connector:                    4-pin Molex
  • Weight:                                     7.3 oz (207 g)
  • Noise (quiet room):               24~26 dBA @ 2′
  • Motor type:            Electronically commutated, brushless DC, spherical
  • Pump MTBF*:                         50,000 Hours


*Note: The 50,000 hr MTBF rating is based on Laing’s performance claims for their brushless DC motor with a lifetime in excess of 50,000 hours when operated at 12V. 


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The Laing DDC pump uses a unique spherical rotor, which contains a small but very strong, two-pole permanent magnet encased in a stainless steel shell.  The spherical rotor/impeller sits on top of a ceramic ball and is held in place and by the magnetic attraction between the rotor magnet and stator poles.  The rotor/impeller is the only moving part in the pump and since there is no rotating motor shaft there is no shaft seal to potentially leak.  The only seal used in the pump is a large O-ring that seals the end casing to the main pump body.  The integral closed style impeller contains 9 curved blades, which are enclosed for greater pumping efficiency. 


The Corsair COOL pump comes with a pre-cut, double-sided adhesive backed neoprene pad, which can be attached to the bottom of the pump prior to mounting.  The pad helps eliminate transmitting vibration and noise to the PC enclosure.  The pump can be attached to a smooth surface, like the bottom of the case or drive bay, by using just the adhesive pad. 


The Laing DDC pump was designed to be compatible with glycol based coolant additives like the Corsair coolant, which helps minimize corrosion and retards the growth of microorganisms.  As mentioned earlier, the DDC is an inline pump and is not designed to be submerged under water.  The pump should never be run dry!  The pump is also not self-priming so the impeller needs to be flooded at all times.


Like most centrifugal pumps, the DDC should be mounted as close as possible to the reservoir with a minimum of bends and/or fittings that could restrict the flow of water into the pump’s suction port. 


I measured the maximum discharge pressure (also referred to as shut-off head or deadhead) of the COOL DDC pump with a calibrated digital pressure gauge (accuracy ± 0.04 PSI).  At 5.24 PSI, it was slightly below the manufacturer’s nominal specification of 5.7 PSI (at 12 VDC) but well above most other pumps commonly used in PC water-cooling systems.


Another valuable piece of information regarding a pump’s performance is the relationship between backpressure and flow rate.  The only time a pump will deliver its maximum rated flow is when there is zero backpressure or resistance to flow.  Each component in a water-cooling system (waterblock, radiator, tubing, fittings, etc.) creates a certain amount of resistance to flow.  This resistance results in a backpressure, which can be measured at every point in the system.  During operation, the pump must overcome the total backpressure in the system to create flow.


The following P-Q curve was generated by measuring and plotting various pressure and flow rates for the Corsair COOL DDC pump. 


Corsair COOL Water Cooling Kit Review - Cases and Cooling 37

 (click to enlarge)


As you can see the DDC pump generates excellent head pressure even at moderate flow rates.  This is particularly well suited to a 3/8′ system.

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