Dual Inlet Forward Curved Blowers
Dual inlet forward curved blowers deliver more airflow at the same impeller diameter, the classic choice for AHU and commercial air conditioning units. Final selection is confirmed at the duty point (airflow / static pressure / voltage / control mode) and by project verification.
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Dual Inlet Forward Curved Blowers — selection guide
Dual Inlet Forward Curved Blowers: 70 models, impellers Ø120–355 mm, maximum airflow 278–8,799 m³/h, static pressure to 1,102 Pa, AC, EC and DC motors, across 20 series. 69 of them carry a measured P-Q curve and 70 a dimensional drawing.
Dual inlet forward curved blowers draw air from both sides of a multi-vane impeller in a scroll housing, which gives more airflow per diameter than any other centrifugal type at low and medium pressure. The line runs from Ø120 to Ø355 mm: LWFA2E120 / 133 / 146 AC blowers, LWFD3G133 / 146 DC blowers (24 / 48 / 310 V) and LWFE3G EC blowers from Ø120 to Ø355 mm, with rotor 92 on most compact sizes and 102 / 138 on the larger ones.
The Ø120–146 mm sizes (52 models) are the classic fan coil and compact AHU blowers; the Ø180–355 mm sizes serve packaged air conditioners, heat-recovery units and ovens.
How to select from this range
- Rate on total pressure at the scroll outlet, including the duct or grille downstream.
- Keep the inlet clear on both sides — the second inlet is where the extra airflow comes from.
- Forward curved blowers are overloading: check motor power at the lowest resistance the system can reach, not only at the design point.
- Choose EC (LWFE3G) for fan coil units with modulating control, DC (LWFD3G) for 24 / 48 V and DC-link equipment, AC (LWFA) for fixed-speed units.
Where these fans are used
- Fan coil units
- Compact and packaged AHUs
- Heat-recovery ventilation units
- Ovens and dryers
Curves marked “measured” come from our own test rigs per AMCA 210 / ISO 5801 methods; digitised catalogue curves are flagged as such in the selector — see the test labs and certificates. Final selection is confirmed at the duty point and by project validation.
FAQ — Dual Inlet Forward Curved Blowers
Why choose a dual inlet over a single inlet blower?
At the same impeller diameter a dual inlet blower moves roughly 1.6–1.8 times the airflow at a similar pressure, so it saves height in a fan coil or AHU casing. A single inlet blower is used where only one side of the impeller can be open.
Which dual inlet sizes are DC?
LWFD3G133 and LWFD3G146 (15 models) in 24 V, 48 V and 310 V, for fan coil units on a DC bus or with an inverter DC link.
What is the maximum pressure of the forward curved blowers?
Up to about 1,100 Pa on the Ø315–355 mm EC units; the compact Ø120–146 mm blowers are used up to 300–500 Pa.