CSI MR-VAV-AX - User Manual

Control Systems
International
®
MR-VAV-AX
Installation Sheet (TCON148 06/97) 1
Installation Sheet
Controller Installation
1. Check the mounting location for the MR-AHU. The MR-
VAV-AX is typically mounted with the controller extending
down or to the right from the damper shaft. However, the
controller can be operated in any position.
Note:
Installing the controller to the right (with the
barbed fittings pointing down) will help to prevent
condensate from migrating into the on-board
velocity sensor.
With a downward extension, the available area around the
damper shaft must measure 6" (160 mm) down from the
lower edge of the shaft, 4.5" (120 mm) to the right, 1.5" (40
mm) to the left and 1.75"(45 mm) above the shaft. Ensure
the location allows enough clearance for servicing.
The actuator is designed to mount over a
1
⁄
2
" (12.7 mm)
diameter shaft with a minimum of 1" (25.4 mm) of exposed
shaft. If the damper shaft is less than
1
⁄
2
" an adapter is
required. The MR-VAV-AX will not work with larger shaft
diameters.
Note:
Optional adapters are available for
3
⁄
8
" (9.5 mm)
diameter damper shafts (CSI Part Number 603500-
0018).
2. If the exposed damper shaft is less than 2" (51 mm) long,
move the two damper shaft mounting screws to the
alternate damper shaft positions (see Figure 1).
3. Select the mounting bracket (see Figure 1) that will provide
the most stability for the operation of the actuator. Position
the mounting clip in the desired mounting bracket. Do not
insert the clip more than half-way into the bracket. This will
allow the clip and the back of the actuator to properly align
with the VAV box.
4. Rotate the VAV damper shaft by hand to the fully closed
position. Note whether the damper is rotated clockwise
(CW) or counter-clockwise (CCW) to close.
5. Slip the controller over the damper shaft. Position the
actuator and, using a self tapping sheet metal screw, secure
the mounting clip to the VAV box. Next, press the actuator
toward the box until the actuator comes into contact with
the VAV box, or the mounting clip snaps into the bracket.
6. Press and hold the red actuator clutch release (see Figure 1)
and rotate the actuator collar to the 5 ° index mark if the
damper shaft was rotated counter-clockwise to close (Step
4). Rotate the actuator collar to the 85 ° index mark if the
damper shaft was rotated clockwise to close (Step 4).
Figure 1. MR-AHU (Covered) Figure 2. MR-AHU (Cover Removed)
LAN -
LAN +
GROUND
POWER
DATA
GROUND
THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES. THE OPERATION
IS SUBJECT TO THE FOLLOWING TWO CONDITIONS:
1) THIS DEVICE MAY NOT CAUSE HARMFUL INTERFERENCE, AND
2) THIS DEVICE MUST ACCEPT ANY INTERFERENCE RECEIVED INCLUDING
INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.
+12V
INPUT 4
INPUT 3
INPUT 2
INPUT 1
OUTPUT 2
OUTPUT 1
OUTPUT 3
24VAC
GROUND
12
11
10
9
8
7
6
5
4
3
2
1
24VAC 50/60 Hz CLASS 2
9VA + EXTERNAL LOAD
(40VA MAX)
MR-VAV-AX CONTROLLER
POWERED BY A SINGLE
CLASS 2 SOURCE
SERIAL NO:
24VAC, CLASS 2
36VA MAX
(12VA MAX EACH)
OUTPUT:
INPUT:
P1
P2
(LO)
(HI)
Alternate
Mounting
Bracket
Mounting Bracket
Cover Release
Actuator Clutch Release
Alternate Damper Shaft
Mounting Screw Position
Damper Shaft
Torx Mounting Screws
Damper
Shaft
Velocity
Sensor
Inputs
Cover Release
Cover Release
Mounting
Clip
U
L
®
LISTED
ENERGY MANAGEMENT EQUIPMENT
MAY BE USED IN PLENUM
APPLICATIONS
63M4
60572-0001
TB1 TB2
TB3TB4TB5
SWITCHES
FUNCTION
SELECT
ADDRESS
SELECT
P.O. BOX 59469: DALLAS, TX 75229
Thermistor/Discrete
Inputs
I/STAT Port
Sub-LAN Port
24VAC Power Input
Control Outputs
Address/Function
Select Dip Switches
Adjustable Stops
Damper Position
Indicator
Alternate Damper Shaft
Mounting Screw Position
Damper Shaft
Collar
Control Systems
®
International
HI
LO
2.9"
2.9"
P3
P4
EPROM
IN OUT
GND
(-)LO
ROM
Memory
4A FB
Replaceable
Fuse

Summary

Controller Installation

Velocity Sensor Connections

Input Device Connections

I;STAT, W;STAT, and S;STAT Connections

Sub-LAN Connections

Auxiliary Fan and Heat Control Connections

Power Supply Connections

Switch Settings

Specifications

Dimensions

Details the physical size of the MR-AHU controller unit.

Damper Shaft Mounting Screws

Specifies torque and screw type for securing the actuator to the damper shaft.

Operating Environment

Defines acceptable temperature and humidity ranges for the controller.

Cable Requirements

Outlines specifications for MR LAN cabling, including length and type.

Inputs;Outputs

Lists digital/analog inputs and output capabilities, including accuracy and resolution.

Overview

1. Function Description
2. Important Technical Specifications
3. Usage Features
4. Maintenance Features

The MR-VAV-AX is a controller designed for Variable Air Volume (VAV) systems, specifically for use with Air Handling Units (AHU). It integrates control functions for damper positioning, velocity sensing, and auxiliary fan/heat control.

Function Description

The MR-VAV-AX controller manages the airflow in a VAV system by precisely controlling the damper position. It receives input from a velocity sensor to monitor airflow and can integrate with various input devices such as thermistors and discrete contacts. The controller also supports auxiliary fan and heat control, allowing for comprehensive environmental management within a zone. Communication with other systems is facilitated via a Sub-LAN port, and it can be configured using DIP switches for specific application requirements, including central plant heat/warmup presence, fan presence, auxiliary heating stages, fan type, S/STAT integration, and damper rotation direction.

Important Technical Specifications

Dimensions:

• MR-AHU: 7.75" W × 6.25" L x 2.5" H (197 mm × 159 mm × 63.5 mm)

Damper Shaft Mounting Screws:

• Torque Minimum: Varies according to shaft material
• Torque Maximum: 30 inch-pounds
• Torx head screws: 10-32 (T25)

Cable Requirements (MR LAN):

• Maximum Length: 5,000 ft. (1,500 m)
• 22 AWG (0.324 mm²) shielded, twisted pair (Belden 9184 equivalent) up to 5,000 feet (1,500 m) maximum.
• Alternatively, 24 AWG (0.206 mm²) shielded, twisted pair (Belden 9841 equivalent) up to 4,000 feet (1,200 m).
• Capacitance: 30 pF/ft. or less between conductors, 55 pF/ft. or less conductor to shield.
• Impedance: 85 to 150 ohm.

Operating Environment:

• Temperature: 32° to 122°F (0° to 50°C)
• Humidity: 10 to 90% RH, non-condensing

Input Power:

• 24 VAC ±10%, 50/60 Hz @ 7 VA plus output load (with I/STAT)
• 24 VAC @ 6 VA plus output load (without I/STAT)

Inputs/Outputs:

• Digital Inputs: Dry Contact, excitation 5 V at 0.5 mA.
• Analog Inputs: 10K Ohm NTC Thermistor, Dale 1M1002-C3 (Reference CSI TTS100 specification).
  • Accuracy: 1%
  • Resolution: 0.4% Span
• Velocity Pressure Input:
  • Span: 0 – 1" (0 – 250 Pa) Water Column
  • Resolution: 0.0043" WC (1.07 Pa)
  • Accuracy: 5% @ 1.00" WC (250 Pa)
• Outputs: 24 VAC @ 0.5A max. each output (1.5A max.).

Usage Features

Installation Flexibility: The MR-VAV-AX can be mounted with the controller extending down or to the right from the damper shaft, though operation in any position is possible. For optimal performance and to prevent condensate migration into the velocity sensor, it is recommended to install the controller to the right with barbed fittings pointing down. Specific clearance requirements around the damper shaft are provided: 6" (160 mm) down, 4.5" (120 mm) to the right, 1.5" (40 mm) to the left, and 1.75" (45 mm) above the shaft.

Damper Shaft Compatibility: The actuator is designed for a ½" (12.7 mm) diameter shaft with a minimum of 1" (25.4 mm) exposed shaft. Adapters are required for shafts less than ½" (e.g., optional adapters for ⅜" (9.5 mm) diameter shafts, CSI Part Number 603500-0018). It is not compatible with larger shaft diameters. If the exposed damper shaft is less than 2" (51 mm) long, the damper shaft mounting screws can be moved to alternate positions.

Mounting and Alignment: A mounting bracket is used to secure the controller to the VAV box. The mounting clip should be positioned in the bracket without being inserted more than halfway to ensure proper alignment with the VAV box. The damper shaft should be rotated to the fully closed position manually before installation, noting its rotation direction (clockwise or counter-clockwise). After slipping the controller over the shaft and securing the mounting clip, the actuator collar is set to a 5° index mark for counter-clockwise closing dampers or an 85° index mark for clockwise closing dampers, using the red actuator clutch release.

Damper Stop Adjustment: If the damper lacks a mechanical open stop or if its open stop is not desired, adjustable stops on the MR-VAV-AX can be set to the desired open position using a ¼" hex driver.

Velocity Sensor Connection: The low pressure side of the velocity sensor connects to P1 and the high pressure side to P2 on the MR-AHU. Specific tubing requirements are provided: maximum 4' (1.4 m) of 0.170" (4.3 mm) I.D. FRPE polyethylene tubing or 0.25" (6.34 mm) O.D./0.125" (3.175 mm) I.D. Tygon tubing. It is crucial to prevent moisture exposure to the velocity sensor; orienting the tubing and controller so that barbed fittings are above the lowest part of the tubing creates a moisture trap.

Input Device Connections: External input devices (contacts or thermistors) connect to terminals TB5-1 through TB5-4. The other lead of the input device connects to the signal ground terminal, TB5-6.

I/STAT, W/STAT, and S/STAT Connections: White, red, and black conductors connect to TB4-1 (Data), TB4-2 (Power), and TB4-3 (Ground). For S/STAT connections, blue and yellow conductors connect to TB5-4 (Input 4).

Sub-LAN Connections: The twisted pair sub-LAN cable's positive lead connects to TB3-1 (LAN+) and the negative lead to TB3-2 (LAN-). Shield drain wire continuity must be maintained across all MR-VAV-AX units, with the shield drain wire connected directly to Electrical Service Earth Ground at only one end of the cable (e.g., at the MCI, MRI, or at one MR-VAV-AX).

Auxiliary Fan and Heat Control Connections: Control relays connect to TB2-1 (Output 1) through TB2-3 (Output 3). The other lead of the control relays connects to earth ground.

Power Supply Connection: The 24 VAC input lead from a separate, isolated 24 VAC transformer connects to TB1-1 (24 VAC). TB1-2 (Ground) connects to earth ground using 14-AWG wire (2.1 mm²). This ground connection should be the same as the neutral lead from the transformer. A proper earth ground connection point is critical before connecting wires to electrical equipment.

DIP Switch Configuration: DIP switches 1-5 define the sub-LAN address (0-31). The ON position is away from the "Open" label. Other DIP switches (SW6-SW12) configure operational parameters such as central plant heat/warmup presence, fan presence, auxiliary heating stages, fan type, S/STAT integration, and damper rotation direction (close direction).

Maintenance Features

Replaceable Fuse: The device includes a 4A FB replaceable fuse (P4), allowing for easy replacement in case of an electrical fault, protecting the internal components.

Actuator Clutch Release: The red actuator clutch release mechanism (Figure 1) allows for manual rotation of the actuator collar, which is useful during installation and for troubleshooting or maintenance, enabling the damper to be moved freely without power.

Damper Shaft Screw Access: The damper shaft is secured by two Torx™ mounting screws, accessible for adjustment or removal using a T25 Torx driver. This allows for easy removal or re-alignment of the actuator if needed.

Troubleshooting Alignment: If the damper does not rotate freely when the clutch is released, it indicates potential misalignment between the actuator and the damper shaft, requiring re-alignment steps (repeating steps 3-5 of installation).

Moisture Management: The recommendation to orient the tubing and controller to create a moisture trap helps prevent condensate from affecting the velocity sensor, reducing potential maintenance issues related to moisture damage.

Grounding Importance: Emphasis on proper earth grounding for all interconnected equipment is a critical maintenance and safety feature, preventing electrical shock or burns and damage to components. The 24 VAC transformer secondary lead and the controller power input terminal (TB1-2) must be securely connected to Electrical Service Earth Ground.

CSI MR-VAV-AX Specifications

General

Brand	CSI
Model	MR-VAV-AX
Category	Control Systems
Language	English