NEW! Halton Max MOS – Airflow management damper (VAV)

Overview

Halton Max MOS is a rectangular airflow management damper that needs no safety distances. This airflow management damper is also designed to function at very low air velocity.

It uses advanced and patented airflow measurement based on the combination of the blade opening and the pressure difference between the blades.

Application areas

• Variable (VAV) and constant (CAV) airflow control applications
• Supply and exhaust installations

Key features

• 0.5-8 m/s airflow velocity
• Maximum differential pressure: 500 Pa over the damper
• Can be connected to Building Management System (BMS)

Operating principle

Fig. 1. Halton Max MOS measuring pressure difference between blades.

Thanks to short (<330mm) and smooth damper casing and uniquely positioned walled measurement probes therein, the flow measurement is based on amplified pressure difference of the damper which enables accurate (±10%) and undisturbed flow control even at low flow velocity (≥0,5m/s).

It also enables challenging flow conditions without the need for in-duct structures, which would cause unnecessary initial pressure losses and challenges for damper cleaning or additional duct sections for safety distance (0-distance). These would cause high additional costs and challenge for damper positioning and installation in other dampers. Also, eventual cleaning of the measurement probes may be done with pressurized air outside of the unit without the need to access measurement tubes or damper blades inside the damper.

Depending on the selected airflow controller, it can receive the airflow control signal via

• Modbus RTU network variable
• BACnet MSTP network variable
• An analog standard signal

The airflow setpoint can be modified between the minimum and maximum settings from the room controller interface or a BMS. The VAV controller can also send the actual value data back to the room interface controller. The communication protocol used for the signal between the room control interface and the VAV controller depends on the actuator model.

Key technical data

Features and options

* Ordered separatly

Control units

A range of control units are available for various application needs.

The control unit includes an integrated dynamic differential pressure sensor. The pressure sensor has a low bypass airflow rate through the sensor element. Depending on the model, airflow rate limits are adjusted on site with a mobile application or a dial for manual adjustment.

Quick selection

The operable airflow range for the Halton Max MOS corresponds to the duct air velocities of 0.5-8 m/s.

Table 1. Operating range, min – max [l/s]

Table 2. Operating range, min – max [m³/h]

Stucture and materials

Dimensions and weight

Fig. 3. Dimensions of Halton Max MOS

Fig. 4. Dimensions of Halton Max MOS, insulated model

Specification

Rectangular pressure-independent variable multiblade airflow control damper for supply and exhaust installations, fulfilling the following requirements:

Construction

• Short (<330mm) and smooth damper casing and uniquely positioned walled measurement probes therein.
• The flow measurement is based on amplified pressure difference of the damper. Accurate (±10%) and undisturbed flow control even at low flow velocity (≥0,5m/s) and challenging flow conditions. Control range at least 1:15
• Closed damper blade air leakage according to EN 1751 class 3.
• Casing air leakage according to EN 1751 class C.
• No internal structures that would cause unnecessary initial pressure losses and challenges for damper cleaning. Eventual cleaning of the measurement probes to be done with pressurized air outside of the unit without the need to access measurement tubes/vanes or damper blades inside the damper.
• No need to install additional duct sections for safety distance (zero safety distance).

Material

• Galvanised or stainless steel (EN 1.4404, AISI 316L)

Electrical data

• Modbus RTU, BACnet MSTP, or analogue connection
• Control signal range of analogue control mode is for input 0…10 VDC or 2 …10 VDC
• Feedback signal range of analogue control mode for output follows the selected control signal range 0…10 VDC
• Power supply voltage 24 V DC/AC

Parameter settings

• Designed airflow range can be set at the factory.
• Controller settings are adjustable on site with bus communication or external service tool.

Accessories

• Sound attenuator for noise reduction. Model with access panel available for easy maintenance.
• Electric reheat coil with an internal heating controller.
• Water coil for heating and cooling

Order code

Order code example

MOS-400-200; SP=N, MA=GS, IN=NA, CU=EX, ZT=NA

Installation

The Halton Max MOS airflow control damper can be installed to T-branch and curve, without safety distances. The accuracy of the measured airflow is given in a table below. Install the unit into the ductwork in such a way that the airflow direction through the unit is as indicated with the arrow label in the unit casing.

Fig. 5. Example of Halton Max MOS installed to duct with no safety distances

Technical performance

• Velocity range 0.5﹣8.0 m/s
• General Measurement Uncertainty
  • Accuracy ±10%
  • The minimum allowed safety distance is 0xD.

Note: The measurement uncertainty is defined in laboratory conditions and may be greater in practical installations, where non-optimal installation situations or multiple consequent disturbances may exist.

Wiring

The wiring must only be carried out by qualified personnel following the local regulations. For the power supply, a safety isolating transformer must be used.

The bus must be implemented according to standard EIA/TIA-485.

Fig. 6. Example: General RS-485 2-wire Topology

For connection and wiring diagrams, see Controller connections and Wiring diagrams in Technical reference data.

Cabling requirements

Field devices:

• The wires connected to the terminals have a cross-sectional area of at least 0.5 mm².
• Twisted-pair cables, shielding recommended.

Modbus RTU or BACnet MSTP cable:

• Shielding twisted-pair. For example, Belden 3105A or Nomak 2x2x0.5+0.5.
• Max. bus length 1000 m.
• To avoid signal reflections, a 120 Ohm termination resistance must be added at the end of the main cable line.

Commissioning

Airflow control

The airflow rates for the Halton Max MOS are preset at the factory. If the airflow rates are not specified by the customer, the default factory settings are 0 for the minimum airflow rate and the nominal value (Vnom) for the maximum rate.

The nominal airflow rates in the following table are given with a pressure level of 110 Pa.

Table 3. Vnom [l/s]

Table 4. Vnom [m³/h]

The actual airflow rate is calculated as a function of different of differential pressure at the measurement probe, blade opening angle and the correct size k factor.

Maintenance

The product is easy to maintain. Normally, the electrical parts do not need maintenance. It is recommended to clean the internal parts of the product when cleaning the ductwork. Refer to the building maintenance program for the maintenance cycle.

Design examples

Office room design example

Description

Office environments place high demands on the ventilation and air quality. Halton Max MOS is perfect for air management in spaces where wide airflow ranges are needed. Silent ventilation system guarantees good working conditions. Minimum maintenance needs prevent creating disturbances in the daily activities.

Design data

• Office/meeting room area 14 m²
• Room minimum airflow 30 l/s
• Room maximum airflow 60 l/s
• Cooling load 500W, 36W/m²

Fig. 7. Halton Max MOS performance

Ventilation design

Fig. 8. Halton Max MOS ventilation design

Components

• MOS with attenuator 600 length
• AGC-500-100
• PRL/F-500-100-200
• 2 x JDS/S-160

Schematic drawing

Fig. 9.Wiring example for Halton Max MOS with a master-slave configuration

In this example, the supply unit is controlling the exhaust unit.

Accessories

Reheat coils (RH)

Fig. 10. Rectangular duct heater, electrical

Halton offers two models of reheater for ducts:

• Water heater/cooler coils are designed for cooling the ventilation air in a ventilation system. The reheater/cooler can also be used for heating or cooling individual rooms or zones.
• Electrical heaters, circular and rectangular, are designed to heat fresh air in a ventilation system.

For more information on the available reheat coils, see section Downloads.

Sound attenuators (SA)

Fig. 11. Rectangular sound attenuator

Halton offers high-quality rectangular and circular sound attenuators for reducing noise levels in the duct.

For more information on the available sound attenuators, see section Downloads.