Details
The Laing DDC 4.2 PWM (DDC4.2P-HT4NWX-01) is a 12 V DC pump of the classic DDC family with PWM speed control: an electronically commutated spherical motor pump only 38 mm tall, with two 3/8" hose barbs for 10 mm ID tubing. This is the bulk version: it ships without the retail box.
Properties
- Model
- DDC 4.2 PWM, DDC4.2P-HT4NWX-01
- Nominal voltage
- 12 V DC
- Connections
- 2x 3/8" hose barb (10 mm ID tubing)
- Speed control
- PWM
- Packaging
- Bulk, no retail box
The first pump for water-cooled workstations
Xylem calls the DDC the first pump to be used in mass-produced, water-cooled workstations. Its small size and output make it a good fit for cooling processors and other electronics, in custom loops, AIO coolers and server cooling.
The spherical motor
The DDC is driven by an electronically commutated spherical motor. Its only moving part is the spherically shaped rotor and impeller unit, which sits on an ultra-hard, wear-resistant ceramic ball; there is no conventional shaft, shaft bearing or shaft seal. Xylem says bearing play, and the noise that comes with it, cannot develop, so the pump stays quiet over its whole service life. The bearing realigns itself and is lubricated by the coolant (wet rotor design), so the pump needs no maintenance.
Reliable and compact
The rotor is held in place magnetically, so small dirt particles are no problem, the rotor cannot lock under normal conditions and the pump starts reliably even after a long standstill. Because the stator wraps all the way around the rotor, the whole pump is only 38 mm tall and fits standard PC cases; separate magnetic shielding is normally not needed. Xylem expects a service life of well over 50,000 hours at 12 V, and every part in contact with the coolant is corrosion resistant.
PWM speed control
This version takes a PWM signal, so a motherboard or fan controller can set the pump speed through its 4-pin fan header while the pump draws its power from the 4-pin Molex plug. The speed signal reports back over the same fan header cable.
Keep the electronics dry
The electronics of the pump are not waterproof (IP32 in the standard version). Make sure no coolant reaches them when you install or service the pump. When you change the top, check that the O-ring seal sits properly, and avoid spills while filling the loop. Never run the pump dry; the coolant lubricates the bearing.
Technical data
| Model | Laing DDC 4.2 PWM, DDC4.2P-HT4NWX-01 |
| Motor | Electronically commutated spherical motor |
| Nominal voltage | 12 V DC |
| Max. system pressure | 1.5 bar (150 kPa) |
| Wetted parts | Stainless steel 1.4571, PPS GF40, EPDM gasket, aluminum oxide |
| Connections | 2x 3/8" hose barb for 10 mm ID tubing |
| Packaging | Bulk, no retail box |
| Dimensions (W x D x H) | 62 x 62 x 38 mm without fittings |
Notes
- Bulk item: the pump ships without the original retail packaging.
- The DDC is the pump originally designed by Laing; Xylem sells it today under its Flojet brand.
In the box
- 1x Laing DDC 4.2 PWM pump (bulk, no retail box)
Xylem's DDC technical drawing is a PDF.






