Product / RDR

Halton RDR – Adjustable airflow regulator

Halton RDR is a compact device designed for in‑duct airflow regulation. It maintains consistent airflow automatically within a defined pressure range.

Installed in circular ductwork, it delivers stable airflow without extra controls and keeps sound levels low.

Suitable for supply and extract air systems
Pressure‑independent operation, no external control required
Acoustic performance defined by sound power level Lw (dB(A))

Overview
Operating principle
Structure and materials
Dimensions
Specification
Installation
Commissioning
Maintenance
Order code
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Overview

The Halton RDR adjustable airflow regulator is an in‑duct airflow management element designed to maintain a constant airflow within a defined pressure range. It is suitable for ventilation and air‑conditioning systems for both supply and extract air and is installed directly inside circular ductwork.

Application areas

Commercial and public buildings
Office buildings, schools and healthcare facilities

Key features

Maintains constant airflow independently of duct pressure fluctuations
Adjustable airflow setting with clear scale and locking mechanism
Suitable for both supply and extract air applications
Compact design for direct installation inside circular ducts
Factory calibrated regulating mechanism

Operating principle

The regulator maintains a constant airflow by means of an internal regulating element that reacts to pressure changes in the duct. Within a pressure range of 50–250 Pa, the regulating element automatically adjusts its position to keep the airflow at the preset value.

The airflow is set using an adjustable airflow module, which can be locked after setting to prevent unintentional changes.

Structure and materials


No.	Part	Material	Note
1	Sleeve with seal	M1-classified plastic	–
2	Spacer	–	According to the airflow
3	Casing	Plastic	–
4	Regulating element	Plastic	–
5	Lock screw	–	Screw to fix the airflow
6	Flow control module	–	–

Dimensions


Size	L	D1	D2
Ø100	68	96	93
Ø125	68	120	60

Fig. 3. Halton RDR, dimensions (Ø 120 – 250)


Size	L1	L2	D1	D2
Ø125	80	86	120	117
Ø160	78	85	148	148
Ø200	82	91	195	195
Ø250	82	120	244	245

The Halton RDR configuration depends on the selected airflow rate. Consequently, different airflow ranges apply for the same diameter. See table below.


Size	Setting	Flow [m³/h]	Set flow [m³/h]
Ø100	RDR Ø80 + 1 spacer	15 to 50	50
Ø100	RDR Ø100	50 to 100	100
Ø125	RDR Ø80 + 1 spacer*	15 to 50	50
	RDR Ø100 + 1 spacer	50 to 100	100
	RDR Ø125	100 to 180	180
Ø160	RDR Ø80 + 2 spacers*	15 to 50	50
	RDR Ø100 + 2 spacers	50 to 100	100
	RDR Ø125 + 1 spacer	100 to 180	180
	RDR Ø160	180 to 300	300
Ø200	RDR Ø80 + 3 spacers*	15 to 50	50
	RDR Ø100 + 3 spacers	50 to 100	100
	RDR Ø125 + 2 spacers	100 to 180	180
	RDR Ø160 + 1 spacer	180 to 300	300
	RDR Ø200	300 to 500	500
Ø250	RDR Ø100 + 4 spacers	50 to 100	100
	RDR Ø125 + 3 spacers	100 to 180	180
	RDR Ø160 + 2 spacers	180 to 300	300
	RDR Ø200 + 1 spacer	300 to 500	500
	RDR Ø250	450 to 700	800

^*Consisting of a double spacer.

Specification

The Halton RDR adjustable airflow regulator is designed for in-duct installation to ensure stable and predefined airflow rates over a wide pressure range.

Materials

The sleeve is made of M1‑classified plastic.
The casing and regulation module is made of plastic.

Structure

Provides constant airflow within a pressure range from 50–250 Pa.
The maximum operating temperature is 60 °C.
Airtightness is ensured by an integrated sealing gasket.
Available duct diameters are Ø100, Ø125, Ø160, Ø200, and Ø250.
Airflow tolerance is ±3 m³/h for airflow ≤50 m³/h and ±5% for airflow >50 m³/h.
Sound power levels (Lw) are expressed in dB(A) and depend on airflow and pressure.

Installation

Installed by direct insertion into horizontal or vertical ducts.
In horizontal duct installation, the DOWN marking on the regulator must be observed.
The airflow direction marked on the sleeve must always be followed.
A leak seal ensures an airtight connection without additional sealing.
Minimum distance to air terminal device:
- Extract air: at least 1Ø.
- Supply air: at least 3Ø.
Do not press or manipulate the regulating element during installation.

Fig. 4. Flow regulator in extraction mode

Commissioning

Airflow must be calibrated before installation.

Loosen the locking screw of the adjustment module by 1/4 turn using a torx n°10 screwdriver
Align the indicator with the required airflow value
Retighten the locking screw to secure the setting

Fig. 6. RDR Ø100 (sample of setting = 50 m³/h)

Fig. 7. RDR Ø125 to Ø250 (sample of setting = 180 m³h)

Maintenance

The airflow regulator must remain accessible at all times
Accessibility is required to allow inspection, verification, and maintenance of the airflow setting