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Indoor grille
Indoor grille

Halton WDD – Universal grille

Horizontal air supply, suitable also for exhaust. Adjustable vertical and horizontal vanes.

  • For cooling and heating applications; suitable also for exhaust
  • Adjustable vertical and horizontal vanes


  • For cooling and heating applications; suitable also for exhaust
  • Adjustable vertical and horizontal vanes
  • Aluminium construction
  • Visible screw fastening.


  • Model with wax-bulb actuator for directing the supply air jet in heating operation
  • Airflow adjustment damper
  • Plenum options with measurement and adjustment functions
  • Installation frame


Halton WDD, rounded frame (R)

LxH L1 L2 H1 H2
200×100 226 176 126 76
250×100 276 226 126 76
300×100 326 276 126 76
300×150 326 276 176 126
400×150 426 376 176 126
400×200 426 376 226 176
500×200 526 476 226 176
600×200 626 576 226 176
800×200 826 776 226 176
1000×200 1026 976 226 176
600×300 626 576 326 276
800×300 826 776 326 276
1000×300 1026 976 326 276
1000×400 1026 976 426 376
1200×400 1226 1176 426 376

With OD (airflow adjustment damper) total depth is 48 mm + 45 mm.
Halton WDD, flat frame (F)

LxH L1 L2 H1 H2
200×100 220 176 120 76
250×100 270 226 120 76
300×100 320 276 120 76
300×150 320 276 170 126
400×150 420 376 170 126
400×200 420 376 220 176
500×200 520 476 220 176
600×200 620 576 220 176
800×200 820 776 220 176
1000×200 1020 976 220 176
600×300 620 576 320 276
800×300 820 776 320 276
1000×300 1020 976 320 276
1000×400 1020 976 420 376
1200×400 1220 1176 420 376

With OD (airflow adjustment damper) total depth is 48 mm + 45 mm.

Special dimensions

In addition to these standard sizes, other dimensions are available by special order. The maximum size is 1500mm x 600mm (LxH).


Part Material Finishing Note
Frame Aluminium Polyester-painted as
white (RAL 9003/ 0% gloss),
anodised or mill finished
Special colours available
Vanes Aluminium Polyester-painted as
white (RAL 9003/30% gloss),
anodised or mill finished
Special colours available
Installation frame Aluminium Option: Concealed
screw (CC) fastening
– galvanised steel
Plenum box / spigot Galvanised steel

The bevel angles of the outer frame have been welded so that the joints are almost invisible.


 Accessory Code  Description
Balancing plenum PRL For balancing and equalising the airflow
and attenuating the duct noise
Plenum BDR Plenum for duct connection
(with or without insulation)
Airflow measurement and
adjustment unit
MSM  For supply installation
Airflow measurement and
adjustment unit
MEM  For exhaust installation
Sound attenuation IN Mineral wool for the Halton BDR plenum box.
Polyester fibre for the Halton PRL plenum box.
Flow adjustment damper OD Aluminium opposite blade damper
for airflow adjustment
Installation frame IF  For installation without plenum
Visible screw fastening SF  Screw fastening
Concealed screw fastening CC  For installation with Halton BDR plenum or IF frame
Wax-bulb actuator MT The actuator controls the vane angle
depending on the supply air temperature

Wax-bulb actuator

In applications, where both heating and cooling are provided, the air pattern can be changed automatically via the wax-bulb actuator.
The wax-bulb actuator alters the angles of the horizontal rear vane depending on the supply air temperature. Neither auxiliary energy nor dedicated control system are needed.

When cold air is supplied at a temperature up to 18°C the supply jet is horizontal. The vane angle is 0°. As the supply air temperature rises, the actuator piston progressively changes the angle of the rear vanes to direct the supply air jet downwards. Vane angle reaches 45° in 10 to 20 minutes.

No maintenance is required for the wax-bulb actuator.

Product models

Halton WDD, rounded frame (R)

Halton WDD, flat frame (F)


Supply air is supplied with horizontal and vertical deflection through the vanes into the space. The supply air mixes with the room air in front of the grille.
The supply air is directed with the horizontal adjustable vanes.
Moving the vertical vanes can change the length and form of the flow pattern.

In wall installations, the recommended distance from the ceiling is 200 mm, when the supply air is directed to the ceiling.
The rear vane angle can also be controlled by optional wax-bulb actuator.

The Halton WDD grille can also be used as an exhaust unit.


For ceiling installation, we recommend using visible screw fastening. The auto screws, 4.2×25 (bevel headed screws) are supplied.

The grille is connected to the circular duct using either a Halton PRL balancing plenum or a Halton BDR plenum or alternatively directly to the rectangular duct using the IF/WDD installation frame.

Installation frame, IF/WDD              Balancing plenum, PRL     Plenum box, BDR

Fastening options

Clips, as standard (CL)

The grilles are delivered with clips fastening as standard.
Clips fastening is used with Halton PRL, Halton BDR and IF/WDD.

Concealed screw (CC)

Concealed screw fastening is possible when the grille is installed with an IF/WDD installation frame or with a Halton BDR plenum, not with a Halton PRL balancing plenum.
Holes are provided for screws in Halton BDR.

For ceiling installation, concealed screw fastening is recommended.

The dimensions of the installation holes are LxH when an installation frame is used, and (L-5) x (H-5) without installation frame.

Visible screw (SF)



In order to enable airflow adjustment and measurement of airflow rate we recommend connecting the diffuser to a Halton BDR plenum or Halton PRL balancing plenum equipped with the MSM module.
The supply flow rate is determined by using the measurement and adjustment module MSM.
Detach the grille and pass the tubes and control spindle through the grille.
Measure the differential pressure with a manometer. The flow rate is calculated using the formula below.

Adjust the airflow rate by rotating the control spindle until the desired setting is achieved.
Lock the damper position with a screw.
Replace the tubes and spindle into the plenum and replace the grille.

The k-factor for installations with different safety distances
(D= duct diameter)

BDR >6xD min 3xD
100 6 7
125 10 12
160 19 22
200 28 32
250 49 51
315 77 83


The airflow rate is selected by measuring the pressure difference between the measurement tap on the Halton PRL balancing plenum or Halton BDR plenum and the room air.
The corresponding airflow rate is calculated and can be adjusted by turning the control spindle of the adjustment unit MEM.

Airflow adjustment damper OD

The airflow rate can also be adjusted by turning the damper blades behind the grille with a screwdriver. The measurement is carried out when grille is installed.


Remove the grille by gently drawing it out by the frame. Use a screwdriver if necessary.
Clean the parts by wiping them with a damp cloth.
Push the grille back into place until the springs lock (or fix by screwing on the concealed screws).

With balancing plenum Halton PRL + MSM (MEM) or Halton BDR + MSM (MEM)

Remove the measurement and adjustment module by gently pulling the shaft (NB not the control spindle).
Wipe the parts with a damp cloth, instead of immersing in water.
Remount the measurement and adjustment module by pushing in the shaft until the module meets the stopper.
Push the grille back into place so that the clips lock.


The grille is made of extruded aluminium, with an anodised or epoxy-painted with a white (RAL9003) standard colour.
The bevel angles of the outer frame are welded so that the joints are almost invisible.
The Halton WDD grille has horizontal and vertical adjustable vanes.
The rear vanes direct the supply air jet horizontally. The length and form of the air pattern are adjusted by turning the front vanes.


The supply air jet shall be controlled according to supply air temperature by a wax-bulb actuator.

Alternative 1

The grille shall be connected to the ductwork using a plenum, with mineral wool as sound insulation material.

Alternative 2

The grille can be connected to the ductwork using a balancing plenum, which comprises sound attenuation material made of polyester fibre with a washable surface.

The plenum comprises an airflow measurement and adjustment unit.
The grille is removable in order to provide access to the measurement and adjustment module in the plenum.

Order code


L = Length (mm)
200, +1, .., 1500

H = Height (mm)
100, +1, .., 600

Other options and accessories

FM = Frame model
R       Rounded
F       Flat

VP = Vane positioning
V       Vertical at front
H       Horizontal at front

FS = Fastening
CL     Clips
SF     Screw fastening
CC     Concealed screw fastening

FI  = Finishing
PN      Painted
AN      Anodised
MF      Mill finished

CO = Colour
SW    Signal white (RAL 9003)
X        Special colour (RAL xxxx)
N        No painting

ZT = Tailored product
N        No
Y        Yes (ETO)

AC = Accessories
WM    Wax-bulb actuator

Sub products

BDR     Plenum
PRL     Plenum
IF         Installation frame (Grilles)
OD      Opposed blade damper (Grilles)

Code example

WDD-200-100, FM=R, FS=CL, FI=AN, CO=N, ZT=N


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