Neptronic Compact Make-up Air Unit

Description

The Neptronic Compact Make-up Air Unit (CMU) is designed to pull in fresh, tempered air from outside a building to replace existing air and continuously provide comfortable ventilation throughout the building. Equipped with intelligent control strategies and the patented Neptronic EAS (Electronic Air Flow Sensors), the CMU maximizes efficiency and optimizes indoor air quality.

The advanced control strategies and optional BACnet MS/TP and Modbus RTU communication modules make it the ideal product for integration with the automation system of intelligent buildings, by enhancing user comfort and reliability.

Features

• Air flow range of 50 to 750CFM (85 to 1274m³/h)
• Sizes from 6" to 12" (152 to 305mm)
• Wide power range (1kW to 20kW)
• Voltage from 120V/1ph to 600V/3ph
• AT between 22°F (11°C) and 86°F (45°C)
• Multiple I/O support for advanced control strategies
• Patented Neptronic EAS (Electronic Air Flow Sensors)
• Ease of operation and maintenance, and enhanced comfort with Neptronic TDF digital room sensors:
  • Display supply temperature
  • Configure CFM and temperature setpoints
  • Monitor alarms
• ECM and AC fan strategies
• Intelligent control strategies:
  • Indoor air quality applications with integrated temperature, humidity, CO2 and occupancy sensor
  • Dehumidification logic
  • Interlock with extraction fans
  • Outside air sensors prime heater coils for fast response and comfort
  • Static pressure PID algorithms, control of fresh air and return air
  • Integrate with BMS and intelligent buildings via BACnet MS/TP or Modbus RTU
  • Safety interlocks and thermal cutouts
  • Schedule support

Network Communication

• BACnet MS/TP or Modbus communication (selectable via DIP switch)
• Select MAC address via DIP switch or via network
• BMS integration via BACnet MS/TP or Modbus
• Multiple BACnet/Modbus points to propel you towards the Internet of Things (IoT)
• Remote monitoring (status, alarms, diagnostics, and trending)
• Real-time feedback of output capacity
• Provides real-time temperature measures and power consumption data

BACnet MS/TP

• MS/TP @ 9600, 19200, 38400, 57600 or 76800 bps
• Automatically assigns device instance
• Automatic Baud Rate Detection

Modbus

• Modbus @ 9600, 19200, 38400, 57600 or 76800 bps
• RTU Slave, 8 bits (configurable parity and stop bits)
• Connects to any Modbus master

Specifications

Technical data

Certification

Complies to standards UL 60335-1 & UL 60335-2-40, CSA C22.2 No. 60335-1 & CSA C22.2 No. 60335-2-40

Models

* This option does not have ETL Certification

Warnings

Caution, Risk of malfunction: In case of alteration (drilling holes or other) to the electrical compartment, ensure proper protection of all electrical components installed. Chips may cause short circuit or affect operation of electrical components.

Caution, Risk of damage and malfunction: Ensure minimum air flow, insufficient air flow will lead to opening of mechanical air flow switch (PDN or PDA) or electronic air flow sensors (EAS) and automatic thermal cutout. This may damage heating elements and controls.

Caution, Risk of malfunction: Do not proceed with modification or alteration to internal electric connections or components of the make-up air unit. Any non-authorized modification will void the warranty.

Important: This appliance is not intended for use by persons (including children) with reduced physical, sensory or mental capabilities, or lack of experience and knowledge, unless they have been given supervision or instruction concerning use of the appliance by a person responsible for their safety. Children must be supervised to ensure that they do not play with the appliance.

Handling

Warning, Risk of failure or malfunction: Do not operate the CMU if heating elements have been damaged during transport or handling.

• Protective packaging must be kept until installation.
• Product must be handled with care.

Dimensions

A diagram showing the dimensions of the CMU unit with labels A, B, C, D, and E is provided.

Models with Axial Fan

Models with Centrifugal Fan

Mechanical Installation

Caution, Risk of electric shock and burns: Personnel must use appropriate personal protective equipment to protect themselves from risk of electric shock and burns due to contact with heating elements and bare live parts. Always proceed with caution when handling and servicing the CMU by following the appropriate lock-out procedures to ensure safety.

Caution, Risk of damage and malfunction: Do not block air flow to heating elements and ventilation slots, as insufficient air flow may damage heating elements and controls.

The compact make-up air unit is designed to be installed for horizontal air flow only. Vertical installation is not recommended.

The CMU is equipped with thermal cutouts both on top and bottom of the unit, which allow it to simply be rotated 180° to change the air flow direction without modifying the fan or wiring. The air flow direction from the fan itself is fixed and cannot be reversed. Before mounting the make-up air, determine the direction of air flow required and rotate the unit accordingly.

The CMU is designed to preheat fresh air and not ambient air.

For proper air flow, a minimum straight duct distance of 2x the collar size/duct diameter must be maintained upstream and downstream the CMU, between the unit and any obstacle, such as dampers, louvers and elbows.

Use round insulated ducts for the inlet connection and uninsulated ducts for the outlet, while ensuring to minimize the use of elbows.

When taking air directly from outside, install the inlet duct at an incline, in order to prevent condensation or melted snow from flowing into the unit.

It is recommended to have a secondary damper before the inlet of the make-up air unit, in order to prevent a strong draft of wind from opening the damper in the unit. The secondary damper can be a gravity damper or a damper with an actuator.

A louver with a bird protection grille must be installed on the air inlet.

A diagram illustrates the recommended duct clearances around the CMU unit.

Clearance

• Leave a minimum clearance of 24" (610mm) or equivalent to the length of the front access panel/door (see dimension E on page 3) + 1.5" (38mm) at the front of the unit, in order to provide sufficient space for accessing the electrical compartment and air filter, to ensure proper servicing.
• Other surfaces require zero clearance.

Insulation

• Insulation may be added around the main surfaces of the CMU for energy conservation and noise reduction. The collars and ductwork preceding and following the CMU may be insulated.
• Insulation must be rated for temperatures of minimum 250°F (121°C) and must not have an R-value greater than 8 (typical R-value for 2" [51mm] thick fiberglass insulation).

Warning: Do not apply insulation on the control box, front access panel, heat sinks and filter of the CMU.

Diagrams show surfaces that can and cannot be insulated.

Wall Mounting

• Prior to installation, ensure that the strength of the chosen wall and supports conform to the requirements of local codes and regulations. The use of metal strut channels is recommended when wall mounting the unit (by others).
• Mount the unit at a minimum height of 6.5ft (2m) above the floor level.
• Mount the CMU using at least 2 screws of minimum #10 (M5) size (by others) using the keyholes located in the back of the unit and ensure that the installation is secure.

A diagram illustrates wall mounting with screws.

Ceiling Installation

• The CMU can be hung by the ceiling using an appropriate support platform (by others). Consult local codes and regulations for minimum structural requirements for such platforms.
• The CMU must be attached to the platform by use of 4 self-drilling screws of #10 (M5) size fixed at the designated locations indicated by the dimples on the bottom of the unit, as per the image below.
• The screws must not be inserted into the CMU at a depth of more than ¾" (20mm).
• Ensure not to install the bottom of the unit's front access panel directly onto the platform, as this will prevent it from opening.

A diagram shows the bottom view of mounting holes and ceiling installation.

Electrical Installation

DANGER: Risk of electric shock. Disconnect all electrical supplies before working on any circuit.

CAUTION: Risk of malfunction. Use only copper wires suitable for 221°F (105°C).

CAUTION: Electric installation must be done by qualified electrician and must conform to local electrical code.

CAUTION: If a disconnect switch has not been supplied with control panel of the unit, an external disconnect switch must be installed on the supply.

CAUTION: Gauge of electric supply wires must be of appropriate section, function of line current, as per local electrical code.

Power Supply Wiring

• See the name plate for information for voltage and current.
• Connect all wires to appropriate terminals as per the electrical diagram affixed inside the control panel door.
• Correct connection and proper tightening must be verified before start-up, and after a short period of operation (typically after 2 weeks).

To quickly calculate the amperage, use the following formulas:

• Single phase: Amperage = Watts / Voltage. ex.: 10 kW at 240V/1 is equal to: 10,000 / 240 = 41.7A
• Three phases: Amperage = Watts / (1.732 x Voltage). ex.: 20 kW at 600V/3 is equal to: 20,000 / (1.732 x 600) = 19.2A

Electrical Diagram Legend

A legend explains symbols for thermal cut-out, contactor coil, back-up safety contactor coil, normally closed contact, normally open contact, disconnect switch, heating element, transformer, fuse, single phase power supply terminals, 3 phases power supply terminals, ground terminal, common, and light.

Main PCB Overview

Diagrams show the layout of the main Printed Circuit Boards (PCBs) labeled MAC1, MAC2, MAC3, and MAC4, with various terminals and components indicated.

* If the MAC10 Room Control Switch is not used, place a jumper between pins 1 & 2.

Temperature and Air Flow Adjustment

After installing and wiring the system, use the potentiometers on the PCB to adjust the desired temperature setpoint (P2) and the fan speed control (P1) to adjust the air volume. The fan speed must be adjusted based on the application to compensate for the specific static pressure of the installation.

For models with the optional add-on board with thermostat connection, the setpoint for air flow and temperature from the thermostat will override the physical setting of the potentiometers on the PCB.

Diagrams illustrate Potentiometer P1 for AC Fan Speed Settings and ECM Fan Speed Settings, and Potentiometer P2 for Temperature Setpoint.

Operational Conditions

Air Flow

• Air flow must not be lower than the minimum air flow indicated on name plate.
• Air flow going through the unit must be free of combustible particles, flammable vapour or gas.
• Open Coil: Air flow going through the unit must be free of dust.

Temperature Control

• For optimal and accurate measurement, it is recommended to use a duct sensor, especially in worst case scenarios in which the CMU is operating at its lowest speed with a high static pressure, for example, at a 75% speed with a static pressure of 0.2" WC (50 Pa) for AC axial fans.

Zero Clearance Construction

Neptronic compact make-up air units are designed and approved for zero clearance to combustible material. Insulation material may be installed directly onto the CMU surfaces or onto air duct. However, the control panel must be accessible for maintenance.

Warning: Risk of fire and/or malfunction, Do not install insulation directly on heating elements.

Fan Performance

Diagrams show Axial Fan Performance (Imperial and Metric) and Centrifugal Fan Performance (Imperial and Metric) with airflow plotted against static pressure for different CMU models.

Add-on PCB Overview (Option)

Diagrams and descriptions detail the connections and settings for the Add-on PCB, including MAC Address DIP Switch (DS1), Baud Rate (DS2), Network settings, Analog Inputs (TB5), Temperature Sensor (TB6), and Analog Outputs (TB7).

MAC Address DIP Switch (DS1)

MAC address for BACnet and Modbus communication, are selectable by DIP switch DS1 using binary logic.

BACnet

• Highest MAC address is 254.
• Default is all switches OFF = MAC address 0
• If you do not change device instance in program mode, it will be automatically modified according to the MAC address.
• MAC Address DS.1 = 1 DS.2 = 2 DS.3=4 DS.4 = 8 DS.5 = 16 DS.6 = 32 DS.7 = 64 DS.8 = 128 Default Device Instance

Modbus

• Highest MAC address is 247.
• Default is all switches OFF = MAC address 1
• MAC address is binary value +1
• There is no device instance for Modbus.
• MAC Address DS.1 = 1 DS.2 = 2 DS.3 = 4 DS.4 = 8 DS.5 = 16 DS.6 = 32 DS.7 = 64 DS.8 = 128

Wiring to TDF Digital Room Sensor

Diagrams illustrate the wiring for the TDF Digital Room Sensor, including connections to the main PCB and optional service port.

TDF PCB Drawing: 3 wire cable (TB1 #1, 2 & 3) Connect TB1 #6 (A+) & #7 (B-) to CMU to enable the BACnet service port.

CO2 sensor: A diagram shows the CO2 sensor connections. Caution: Avoid touching the CO2 sensor as this may cause incorrect readings.

Mode Selection (JP1): The jumper settings for RUN (Operation Mode) and PGM (Programming Mode) are explained.

Access to Menus (Add-on PCB and TDF Required)

The programming menu can be accessed using the TDF digital room sensor by connecting it to the optional add-on PCB. Ensure that the TDF Mode Selection jumper (JP1) is set to PGM. Use the following action buttons to access the menus and save changes using the TDF.

Action Buttons on TDF

LED Error Sequence

The output on the LED will show when the alarm is active. Following is the LED error sequence:

* Other scenarios can include but not limited to: 1. Error in Feedback for ECM Fans, 2. Incorrect configuration of the IO's on the COM board, 3. Communication error between Add-on and Host Board. For the above scenarios, please contact tech support at the factory for assistance.

Inputs – Menu Overview (1 of 4) | Al1 to Al4

This section details the configuration of Analog Inputs (Al1 to Al4) through the TDF interface, covering modes, signal ranges, and specific sensor types like SAT, OAT, SARH, OARH, Static Pressure, Fan Speed Setpoint, and Damper Feedback.

Outputs – Menu Overview (2 of 4) | AO1, AO2, BO1 and BO2

This section outlines the configuration of Analog Outputs (AO1, AO2) and Binary Outputs (BO1, BO2), including modes, delay settings, and signal ranges for fan and damper control.

Control – Menu Overview (3 of 4) | Ctrl

This section describes the control parameters available through the TDF interface, including temperature control modes, setpoint sources, PID control settings, and CO2 extract configurations.

Alarm – Menu Overview (4 of 4) | Alar

This section details the various alarm conditions that can be configured and monitored, such as thermal cutout alarms, communication timeouts, airflow alarms, and invalid configuration alarms.

Operation Menus

This menu is accessible through normal operation mode using the TDF digital room sensor. The Mode Selector jumper (JP1) must be set to the “RUN” position. Pressing the arrow buttons simultaneously for 5 seconds brings up the “ENTER PASSWORD” screen. Passwords 637 for Network Settings and 757 for Configuration are provided.

Menu 637 – Network Settings

This menu allows configuration of MAC Address, Baud Rate, Network type (BACnet or Modbus), Comport configuration, and communication timeouts.

Menu 757 - Configuration

This menu provides extensive configuration options for the unit, including airflow setpoints, pressure setpoints, temperature setpoints, PID control parameters, scheduling, and offset adjustments.

Maintenance

Neptronic make-up air units do not require specific maintenance; however, a yearly inspection is recommended, typically before the winter season or after a long term shut down.

Visual Inspection

Risk of electric shock: Disconnect all supplies before any visual inspection.

• Verify condition of heating elements.
• Heating element must be clean and free of dust or lint.
• Open Coil: Carefully verify that there is no dust accumulation. Any dust of lint accumulation can lead to fire hazard.
• Verify any indication of overheating conditions (discoloration) as well as any trace of oxidation (rust).

Electrical Inspection

Risk of electric shock: Disconnect all supplies before any electrical inspection.

• Verify that electrical connections are correct and properly tightened.
• Verify the condition of fuses.
• Verify resistance of each circuit against ground.
• Verify correct operation of contactor(s).
• If necessary, electrical components must be replaced only with identical origin components.

Filter Maintenance

Risk of electric shock: Disconnect all supplies before removing and inspecting the filter.

• CMU is equipped with a filter that must be washed at regular intervals.
• Check the filter after two months of operation.
• To take out the filter, remove the access cover by disconnecting the two screws.
• If the filter is extremely dirty, increase the frequency of inspections.
• Ensure that the filter is dry before replacing it.

Warning: The CMU must always have a filter installed at this location even if an auxiliary filter is used.

A diagram shows the filter location.

General Warranty

This product is subject to the terms and conditions described at http://www.neptronic.com/Sales-Conditions.aspx.

Technical Support

For any questions or specific requests, please consult our web site: www.neptronic.com

Or call: 1 800 361-2308 or (514) 333-1433.