Titus Mixing Box User Manual
Installation Manual
IOM-MBC-00 08-30-04
Mixing Box Control Systems
Installation, Operation, and Maintenance Manual
Contents Page
Introduction.............................................................1
General ....................................................................1
Safety .......................................................................1
Inspection................................................................1
Mixing Box Control Systems.................................2
Integrated Economizer System Operation.........................2
Diagnostic Equipment .......................................................2
Three-Position Control System.............................2
Three-position Damper Motor – M8405A ..........................2
Logic Module – W7459C ................................................... 4
Solid-State Enthalpy Sensor - C7400A .............................5
Verification and Troubleshooting.......................................6
Modulating Control System...................................8
Modulating Damper Motor – M7415A................................8
Logic Module – W7459A .................................................10
Solid-State Enthalpy Sensor - C7400A ...........................12
Air Temperature Sensor – C7150B .................................12
Verification and Troubleshooting.....................................15
Abbreviations........................................................15
Introduction
This document provides installation, operation, and
maintenance information for the mixing box control
systems.
General
The following information is to be used by the installer as a
guide. Since each installation is unique unto itself, only
general topics are covered. The order in which topics are
presented may not be required by the actual installation.
This guide is not intended to supersede or circumvent any
applicable national, state, or local codes.
The installation is to be performed only by individuals
whose experience meets or exceeds the requirements of
the work involved.
The installer MUST read the entire contents of this guide
and develop a thoroug
installation.
Due to a continuing program of product research, Titus
reserves the right to discontinue or change without notice,
any or all specifications or designs without incurring
obligations.
h understanding before beginning
Safety
Titus requests the following information be read and
understood prior to installation.
The installation and/or servicing of comfort conditioning
equipment can be hazardous due to system pressures
and electrical devices.
Caution: Only trained and qualified personnel
should perform service and/or i
Observe all precautions and warnings in the
product data or attached to the unit.
Follow all safety codes. Wear eye protection and gloves.
Have a fire extinguisher readily available.
Caution: Disconnect all power supplies before
accessing equipment.
Disconnecting more than one power supply may
be required to de-energize some equipment.
DANGER
ELECTRIC SHOCK CAN CAUSE DEATH.
Caution: Read these instructions carefully. Failure
to follow them could result in damage to the
product or cause a hazardous condition.
• Check the ratings given in the instructions and on the
product to ensure the product is suitable for your
application.
• Only trained and qualified personnel should perform
service and/or installation.
• After installation is complete, checkout product
operation as provided within this document.
nstallation.
Inspection
Thoroughly inspect all packages upon receipt. Ensure
carton(s) have not be
Inspect all contents for damage. If damage is found,
immediately file a claim with the delivering carrier.
en dropped, crushed or punctured.
605 Shiloh Road • Plano, Texas 75074 • 972- 212-4800
All rights reserved. No part of this work may be reproduced or transmitted in any form or any means, electronic or mechanical, including photocopying and recording, or by any information storage retrieval system without permission in writing from Air Distribution Technologies.
Mixing Box Control Installation Manual
IOM-MBC-00 08-30-04
Mixing Box Control Systems
Titus offers two types of mixing box control system
packages, they are:
• Three-Position Control System.
• Modulating Control System.
The following segments discuss each system and its
components in detail, with the exception of the ball joints
and pushrods. The setup shown in Figure 1 is logic
module connected to a damper motor in a dedicated
arrangement.
Figure 1. Dedicated Logic Module and Damper Motor
Arrangement
Integrated Economizer System Operation
The purpose of an economizer is to use outdoor air for
cooling, whenever possible, to reduce compressor
operation. An economizer control system includes a
cooling thermostat and a solid-state enthalpy changeover
sensor. This allows it to respond to both dry bulb
temperature and humidity, allowing the use of outdoor air
temperatures for free cooling when humidity is low.
The
economizer functions as a first stage of cooling and
provides maximum economy during the cooling cycle. The
economizer is automatically locked out during heating by
holding the outdoor air damper at the minimum position
setting.
On a call for cooling by the space thermostat, the system
operates as follows:
When the sensed enthalpy of the outdoor air is below the
set point, the outdoor air damper is modulated open (and
return air damper is modulated closed) to maintain
between 50 and 56º Fahrenheit at the
sensor. The second stage cooling uses the mechanical
cooling during the economizer operation.
mixed/discharge air
When the sensed enthalpy of the outdoor air is above the
set point, the outdoor air damper closes to its minimum
position. On a call for cooling from the space thermostat
brings on mechanical cooling.
During the unoccupied period, the damper motor will
spring return the outdoor air damper to full closed position.
Diagnostic Equipment
In addition to either control system package, the following
diagnostic equipment (supplied
beneficial to the installation, verification, and/or
troubleshooting processes.
• 1.2k ohm checkout resistor
• Remote minimum position potentiometer
• Minimum position potentiometer
• Remote bulb control for low ambient lockout
• Board for panel mounting logic module
by others) may be
Three-Position Control System
Components list of the three-position control system is as
follows:
Table 1. Package Contents
Part Code Description Quantity
M8405A Three-position Damper Motor 1
W7459C Logic module 1
C7400A Solid state enthalpy sensor 1
27518 Ball joints 2
27520E 18-inch pushrods 2
Three-position Damper Motor – M8405A
Spring-return, 25-inch/pound damper motor (actuator)
provides three-position control of economizer systems or
ventilation dampers. Spring returns motor shaft to normal
position on power interruption. The following figure depicts
a damper motor.
Note: Damper motors may be referred to as
actuators.
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Mixing Box Control Installation Manual
Figure 2. Three-Position Damper Motor
IOM-MBC-00 08-30-04
Installation
When planning the installation, allow ample clearance for
maintenance and service. Ensure the location is protected
from rain and snow. The following steps provide basic
instructions to install a damper motor.
Position damper motor on mixing box where
1.
mounting is desired.
Note: Motor placement may restrict crank arm
rotation. Position motor to allow widest range
of crank arm rotation, see Figure 3.
Use the damper motor holes as guides and
2.
drill four holes into mixing box.
Secure the damper motor to mixing box using
3.
four screws. Figure 4 shows a typical damper
motor to mixing box installation.
Operation Ratings
The following table highlights operational information.
Table 2. Operating Ratings
Operation Rating
Synchronous Normally closed
Power VA 7
Timing (sec.) 90
Stroke
Application
Timing 90 seconds
Voltage and
frequency
Maximum operating
torque
Ambient temperature
rating
Shaft
Approximate
dimensions
Component recognized by Underwriters Laboratories, Inc.
90 degrees, opens counterclockwise as viewed from power
end.
Three-position, with adjustable
minimum position control
24 Vac, 50/60 hertz
25-inch/pound (2.8N-M)
-25° to +125° Fahrenheit (-32° to
+52° Celsius) at 25 percent duty
cycle.
Single-ended drive with crank arm
supplied.
4.5 inches (114 millimeter) high; 5
inches (127 millimeters) wide, and
5.188 inches (132 millimeter)
deep.
Note: Possible 90 degree arm rotation, based on
motor positioning.
Figure 3. Crank Arm Rotation Limits
Figure 4. Typical Damper Motor to Mixing Box
Installation
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IOM-MBC-00 08-30-04
Settings and Adjustments
Connect 24 Vac to motor at terminals T and X
1.
(Terminal D is not connected).
Adjust thumbwheel on motor for desired minimum
2.
position.
Operation
A single-pole, single-throw (SPST) low-voltage controller
is used to control the three-position Damper Motor.
• Fully open – when controller provides 24 Vac to D
and T, motor is energized and drives fully open.
• Fully closed – when power is removed from
terminals T and D, and the motor spring returns to the
fully closed position.
• Mid-position – when controller provides 24 Vac to T
and X, motor is energized and drives to the adjustable
mid-position (minimum position)
An adjustable minimum position can be reached from
either the fully closed or fully open position. From fully
closed, the motor drives open to the minimum position;
from fully open the motor spring returns to the minimum
position.
.
Verification
Operate the motor through its complete open-close stroke.
If necessary, release one of the previously tightened
linkage connections to prevent damage. Check for proper
operation, ensuring the linkage does not bind and the
motor travels smoothly throughout its fully open and full
closed positions. This motor checkout ensures:
1. The motor operates the load.
2. The motor responds properly to the controller.
There is no binding of the linkage or
3.
at any point of travel.
If motor does not operate properly, check for proper
voltage or mechanical binding in linkage or damper.
If questions arise regarding this product, contact your
distributor or Titus representative.
motor stalling
Logic Module – W7459C
The logic module provides control for the damper motor.
Use the enthalpy set point of the logic module to select air
temperature and humidity suitable for free cooling. Figure
5 depicts the logic module.
Remote Minimum Position Control
Remote control of the outdoor air dampers can be used, if
temporary additional ventilation is required. The
potentiometer in the logic module – W7459 controls the
minimum position of the dampers.
Operation
Table 4 provides operational information.
Figure 5. Three-Position Logic Module
Table 4. Operational Ratings
Operation Rating
Operating ambient
temperature
Humidity
Input voltage
Relay contact rating
at 24 Vac
Application
Discharge air
temperature input
Minimum position
potentiometer
adjustment
Terminals for remote
minimum damper
position
Output relays 2 single-pole, dual-throw (spdt)
25º Fahrenheit t
Fahrenheit (32 to +52º Celsius)
5 to 95 percent relative humidity
24 Vac, 50/60 hertz
1.5 A run, 3.5 A inrush
Use with three-position Damper
Motor - M8405A
Single-pole, single-throw (spst)
None
(Minimum position adjustment is
built into Damper Motor M8405)
None
to +125º
p
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Mixing Box Control Installation Manual
Installation
The logic module mounts on the side of the three-position
damper motor (M8405A). When planning the installation,
allow enough clearance for maintenance and service.
Ensure the location is protected from rain and snow.
1. Align logic module to prongs of the Damper Motor.
2. Press logic module and Damper Motor together.
Secure logic module to damper motor using the
3.
supplied mounting screw.
Settings and Adjustments
The minimum position potentiometer keeps the outdoor air
damper from closing completely during system operation
to provide ventilation. Figure 6 shows potentiometer
adjustment slots. Use a screw
Connect 24 Vac at terminals TR and X (D is not
1.
connected).
Adjust thumbwheel on motor for desired minimum
2.
position.
Wiring
Disconnect power supply before connecting wiring to
prevent electrical shock or equipment. All wiring must
comply with applicable local codes, ordinances, and
regulations. See Figure 7 for wiring diagram depicting the
three-position control system.
driver to make adjustments.
IOM-MBC-00 08-30-04
Figure 6. Enthalpy Set Point Potentiometer (Three-
Position System)
Solid-State Enthalpy Sensor - C7400A
The solid-state enthalpy sensor – the C7400A has a solidstate element that senses temperature and humidity. It
combines solid-state enthalpy changeover control,
minimum damper position potentiometer and compressor
staging relays.
The solid-state enthalpy sensor – C7400A when
the Solid State Economizer Logic Module – W7459 and
three-position damper motor – M8405 helps to position
outdoor and return air dampers in economizer systems.
Figure 8 depicts the solid-state enthalpy sensor.
Use for enthalpy control as follows:
• One sensor in outdoor air for single enthalpy control.
• Two sensors, one in return air and one in outdoor air,
for differential enthalpy control. Contact a Titus
representative, if specifications call for differential
enthalpy control.
The enthalpy set point of the logic module selects the air
temperature and humidity suitable for free cooling.
Operational Ratings
Table 6 highlights operational ratings.
used with
Figure 7. Three-position Control System Circuit
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