Neptronic CMU Series - User Manual

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Compact Make-up Air Unit

Specification and Installation Instructions

Compact Make-Up Air Unit-210802 Page | 1

Description

The Neptronic Compact Make-up Air Unit (CMU) is designed to pull in

fresh, tempered air from outside a building in order 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.

CMU Series

Features

• Air flow range of 50 to 750CFM (85 to 1274m

/h)

• Sizes from 6” to 12” (152 to 305mm)

• Wide power range (1kW to 20kW)

• Voltage from 120V/1ph to 600V/3ph

• ΔT 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, CO

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

CMU Series

Maximum outlet air temperature

200˚F (93˚C)

Maximum operating outlet temperature

95˚F (35˚C)

Inlet bushing

2 knockouts of 1 ⅜’’ (35mm) or 1 ¾” (44.5mm)

Control signal

Modulating or Vernier control (select models)

Fan

AC or ECM fan

Air flow direction

Horizontal with reversible installation

Voltage, Current, Power, and Minimum air flow

See name plate

Certification

4011008

Complies to standards UL 60335-1 & UL 60335-2-40,

CSA C22.2 No. 60335-1 & CSA C22.2 No. 60335-2-40

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Overview

Function Description
Important Technical Specifications
Models (Collar Size, Voltage Code, Heating Capacity, Fan Type, Power Switch)
Usage Features
Maintenance Features

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. It is equipped with intelligent control strategies and patented Neptronic EAS (Electronic Air Flow Sensors), which optimize energy efficiency and minimize indoor air quality. The advanced control strategies and optional BACnet MS/TP and Modbus RTU communication modules make it ideal for integration with building automation systems, enhancing user comfort and reliability.

Function Description

The CMU functions as a make-up air unit, drawing in outside air, tempering it to a desired temperature, and supplying it to the building. This process ensures continuous ventilation and helps maintain indoor air quality. The unit features intelligent control strategies and electronic air flow sensors to optimize energy efficiency. It can be integrated into building automation systems via BACnet MS/TP or Modbus RTU communication, allowing for centralized control and monitoring. The unit is designed for horizontal airflow only and can be rotated 180° to change the airflow direction without modifying the fan or wiring.

Important Technical Specifications

Maximum outlet air temperature: 200°F (93°C)
Maximum operating outlet temperature: 95°F (35°C)
Inlet bushing: 2 knockouts of 1 ½” (35mm) or 1 ¾” (44.5mm)
Control signal: Modulating or Vernier control (select models)
Fan: AC or ECM fan
Air flow direction: Horizontal with reversible installation
Voltage, Current, Power, and Minimum air flow: See nameplate
Certification: Intertek 4011088. Complies to standards UL 60335-1 & UL 60335-2-40, CSA C22.2 No. 60335-1 & CSA C22.2 No. 60335-2-40.

Models (Collar Size, Voltage Code, Heating Capacity, Fan Type, Power Switch):

CMU06 (Small): 6" collar, 120VAC/1ph to 600VAC/3ph, 1kW to 20kW heating, AC Axial or ECM Axial/Centrifugal fan, Disconnect Switch or None.
- Dimensions: A: 23 [584], B: 7.6 [193], C: 13.3 [338], D: 6 [152], E: 14.7 [373]
- Maximum Air Flow: 150 [255] CFM [m³/h]
- Maximum Power: 3kW
CMU08 (Large): 8" collar, 120VAC/1ph to 600VAC/3ph, 1kW to 20kW heating, AC Axial or ECM Axial/Centrifugal fan, Disconnect Switch or None.
- Dimensions: A: 28.9 [734], B: 9.6 [244], C: 15.3 [389], D: 8 [203], E: 14.7 [373]
- Maximum Air Flow: 200 [340] CFM [m³/h]
- Maximum Power: 8kW
CMU10 (Large): 10" collar, 120VAC/1ph to 600VAC/3ph, 1kW to 20kW heating, AC Axial or ECM Axial/Centrifugal fan, Disconnect Switch or None.
- Dimensions: A: 30 [762], B: 11.6 [295], C: 17.3 [439], D: 10 [254], E: 16.7 [424]
- Maximum Air Flow: 400 [680] CFM [m³/h]
- Maximum Power: 12kW
CMU12 (Large): 12" collar, 120VAC/1ph to 600VAC/3ph, 1kW to 20kW heating, AC Axial or ECM Axial/Centrifugal fan, Disconnect Switch or None.
- Dimensions: A: 28.8 [732], B: 13.8 [351], C: 19.3 [490], D: 12 [305], E: 16.7 [424]
- Maximum Air Flow: 750 [1274] CFM [m³/h]
- Maximum Power: 20kW

Usage Features

Air Flow Range: 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
Ambient Temperature: 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): Ensures constant air flow and optimizes energy consumption.
Ease of Operation and Maintenance: 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: Integrated temperature, humidity, CO2, and occupancy sensors.
Dehumidification Logic: Integrated with extraction fans.
Outside Air Sensors: For colder climates.
Static Pressure PID Algorithms: Control of fresh air and return air.
Integrated with BMS and Intelligent Buildings: BACnet MS/TP or Modbus RTU.
Safety Interlocks and Thermal Cutouts: For enhanced safety.
Schedule Support: For programmed operation.
Installation: Designed for horizontal airflow only. The unit can be rotated 180° to change airflow direction.
Clearance: A minimum clearance of 24" (610mm) or equivalent to the length of the front access panel/door (dimension E on page 3) + 1.5" (38mm) is required at the front of the unit for accessing the electrical compartment and air filter. Other surfaces require zero clearance.
Ductwork: Minimum straight duct distance of 2x the collar size/duct diameter must be maintained upstream and downstream of the CMU. Use round insulated ducts for the inlet and uninsulated ducts for the outlet.
Outdoor Air Intake: Install the inlet duct at an incline to prevent condensation or melted snow from flowing into the unit. A secondary damper (gravity or actuated) and a louver with a bird protection grille are recommended for the air inlet.
Mounting: Can be wall-mounted (minimum 6.5ft/2m above floor, using at least two #10/M5 screws in keyholes) or ceiling-hung (using a support platform and four #10/M5 self-drilling screws in designated dimples on the bottom).
Insulation: Insulation may be added around the main surfaces for energy conservation and noise reduction. Collars and ductwork can also be insulated. Insulation must be rated for minimum 250°F (121°C) and have an R-value greater than 8 (e.g., 2" [51mm] thick fiberglass). Do not apply insulation on the control box, front access panel, heat sinks, and filter.
Temperature and Air Flow Adjustment: Potentiometers on the PCB (P1 for fan speed, P2 for temperature setpoint) allow adjustment. An optional add-on board with thermostat connection can override these physical settings.
Operational Conditions: Airflow must not be lower than the minimum indicated on the nameplate and must be free of combustible particles, flammable vapor, or gas. Open coil units require dust-free airflow.
Temperature Control: A duct sensor is recommended for optimal and accurate temperature measurement, especially at low fan speeds with high static pressure.
Zero Clearance Construction: Designed and approved for zero clearance to combustible material. Insulation can be installed directly on CMU surfaces or air duct, but the control panel must remain accessible.

Maintenance Features

Yearly Inspection: A yearly inspection is recommended, typically before winter or after a long shutdown.
Visual Inspection:
- Disconnect all supplies before inspection.
- Verify the condition of heating elements, ensuring they are clean and free of dust or lint.
- For open coil units, verify no dust accumulation to prevent fire hazards.
- Check for any signs of overheating (discoloration) or oxidation (rust).
Electrical Inspection:
- Disconnect all supplies before inspection.
- Verify electrical connections are correct and properly tightened.
- Check the condition of fuses.
- Verify resistance of each circuit against ground.
- Verify correct operation of contactor(s).
- Replace electrical components only with identical origin components if necessary.
Filter Maintenance:
- Disconnect all supplies before removing and inspecting the filter.
- The CMU is equipped with a filter that must be washed at regular intervals.
- Check the filter after two months of operation.
- To remove the filter, disconnect two screws from the access cover.
- Increase inspection frequency if the filter is extremely dirty.
- Ensure the filter is dry before replacing it.
- A filter must always be installed, even if an auxiliary filter is used.

Neptronic CMU Series Specifications

General

Brand	Neptronic
Model	CMU Series
Category	Air Handlers
Language	English